Authors have been working on vegetation experiment using Greening Soil Material (GSM) to establish measures for combating desertification in Southern Mongolia. GSM can control moisture and nutrient retention capacity in shallow part of ground for growing plants healthily by only mixing local sand and dried animal feces. Each material can be collected in the vicinity of the target site. GSM is effective when buried at a depth of 0.05-0.1 m below ground level. Therefore, using GSM can be achieved a low-cost and environmental-friendly method. A targeting plant, licorice (Glycyrrhiza uralensis Fisch.), is one of the most valuable medicinal plant, but its distribution area has been shrinking due to soil deterioration. Therefore, planting licorice by using GSM could be sustainable and high value-added revegetation which can be accomplished revegetation with cultivation. In this paper, as one of the methods to evaluate the survival rate of licorice from the installation conditions and initial physical and chemical environment of GSM. A machine-learning model was employed for the logistic regression analysis, and the proportion of appropriate training data to improve the prediction accuracy was examined. In addition, the obtained regression equation was used to predict the survival rate of licorice from GSM validation data which were not used in the model.

Since the Industrial Revolution, the concentration of carbon dioxide (CO₂) in the Earth’s atmosphere has risen rapidly. CO₂ is known as a type of greenhouse gas, thus global efforts are being made to reduce CO₂ emissions. In this study, we conducted a field experiment to verify the amount of CO₂ fixed in biomass by afforestation with fast-growing paulownia. The experimental sites were located in Fukushima Prefecture, Japan. 7.5-year-old fast-growing paulownia trees were surveyed in two sites (site H, located valley and originally farmland; and site INA, located lake side and originally wasteland.). The survey included tree height, girth at breast height (GBH), and measurement of essential plant elements concentration in the soil. In addition, trees were harvested, and biomass weight was measured in the site H. The average tree height was about 16 m at site H, and only about 11.4 m at INA. The average GBH was over 70 cm at site H, and about 56 cm at INA. Among the elemental concentrations in the soil, P and N concentrations decreased significantly during the growth of Paulownia. The biomass weight of cut down trees at site H was about 560 kg on average, and the correlation between the biomass weight and tree height and GBH was examined, and it showed a strong correlation with GBH. Based on this relationship, an allometric equation was derived and CO₂ absorption by fast-growing paulownia trees was estimated to be 46.8 t-CO₂/ha/year, which is much higher than that of afforestation species such as Japanese cedar and eucalyptus.

In situ electrochemical degradation of trichloroethylene (TCE) is one of the promising options for low-cost remediation of TCE. However, actual TCE degradation has not yet been established in our study because of the compound’s volatility and adsorption onto soil surfaces. In this study, degradation of TCE in a model soil by an electrochemical process was confirmed by GC-ECD, TOC, IC, GC-MS, and ion chromatography analyses. The electrochemical degradation was performed in a model soil consisting of glass beads and aqueous solution, and the residual TCE and degradation products were determined. Complete decomposition of TCE to CO₂ and chloride ion was achieved by application of a 10 V d.c. voltage.

Desert greening and animal feed production are needed in the Republic of Djibouti, in east Africa. It is important to have information on the plants that are abundant in Djibouti. The Global Biodiversity Information Facility (GBIF) database records the occurrence of organisms worldwide by integrating specimens and discovery information. This study collected basic data on plant species in Djibouti, especially with regard to the frequency of occurrence of vascular plants, using the GBIF database, to understand the potential for greening and grazing.

In total, 6982 vascular plants from 561 species were in the GBIF database. The literature reports 783 vascular plant species in Djibouti. Thus, 71.6% of the species are in the GBIF database. The most frequently registered family was Fabaceae (19.2%), followed by Poaceae (10.9%), Asteraceae (8.0%), Solanaceae (4.8%), Malvaceae (4.4%), and Euphorbiaceae (4.4%). The most frequently registered species were Vachellia (previously Acacia) tortilis (3.8%), Solanum somalense (2.2%), and Rhigozum somalense (2.1%). Vachellia spp. accounted for five of the top 10 species. Fabaceae can grow on infertile soil because of nitrogen fixation. Poaceae and Asteraceae are recently evolved plant taxa that have adapted to arid land. The rank-frequency relationship of families and species (log-log scale) was significantly linear, where x denotes rank order of families or species, and y denotes frequency of occurrence, (log(y) = -1.24 log(x) + 7.70, (R² = 0.93, P < 0.001), log(y) = -0.521 log(x) + 5.48, R² = 0.98, P < 0.001), following Zipf’s law.

The tsunami associated with the Great East Japan Earthquake on March 11, 2011, caused devastating damage to the Pacific coast of eastern Japan. Especially in Miyagi Prefecture, about 15,000 ha of agricultural land was damaged. The authors have been involved in earthquake recovery support for 10 years by proposing the effective use of such damaged areas.The objectives of this study were to introduce 1) the activities suggested by the Commission of Agricultural Development for Arid Lands, the Japanese Association for Arid Land Studies and 2) activities to use uncultured fields for willow biomass production. Several symposiums with field tours in Miyagi Prefecture, Japan were conducted in 2012-2016. Information exchange between local stakeholders and farmers regarding the improvement of salt damage and the utilization of soil with low fertility was conducted in the symposiums. Such activities could provide reconstruction support to local people. As a part of the extensive effective utilization of tsunami-stricken farmlands, a cultivation test was conducted using fast-growing willow (Salix spp.), and biomass production was attempted. Cultivation trials were conducted in two fields in Watari Town, Miyagi Prefecture, Japan in 2014-2020. The yields cultivated from the two fields after 3-4 years amounted to 5.0-19.1 and 9.0-10.7 t·ha^-1·y^-1, respectively. A clone named KKD on both sites can grow in a range reported in previous studies, even in sandy soil, by efforts to optimize clone selection and cultivation techniques, such as mulching for successful harvesting. In the future, we would like to utilize the knowledge obtained in the trials for further desertification prevention studies and activities.

Soil and water contamination with volatile organic compounds (VOCs) is a global environmental problem, including developing countries with semi-arid climates. One particular VOC, 1,4-dioxane, is a suspected carcinogen and difficult to remove from contaminated sites. Phytoremediation of 1,4-dioxane is expected to be an inexpensive, effective, and widely applicable method, even at sites with low soil moisture. Some species of willows were used for forestation in semi-arid areas because of their relative drought tolerance. This study aims to assess the potential of willows (Salix) for phytoremediation of 1,4-dioxane (volatilization, metabolization, and accumulation), and to clarify differences between three willow species in 1,4-dioxane phytoremediation features. This investigation tests the removal efficiencies of 1,4-dioxane from solution by the species KKD clone which shows extreme fast-growing, FXM clone which shows relatively strong drought tolerance, and SEN which shows relatively strong insect resistance. In hydroponic tests, 1,4-dioxane was removed by 32.8%±12.4% for KKD, 15.0%±6.4% for SEN, and 12.0%±8.5% for FXM, of the initial amount of 4000 µg. Mechanistically, volatilization, metabolization, and accumulation accounted for 68.7%, 18.5%, and 2.4%, respectively, of 1,4-dioxane removal in KKD.

Arid land afforestation are attracting as a way to combat global warming. The authors considered the use of afforestation trees as biomass for petroleum alternative liquid fuels. The tendency of liquefaction of woody biomass differs depending on the solvent. The previous study reported that a high yield of liquefied oil with high polarity can be attained by using an alkaline aqueous solution as a solvent. However, liquefied oil with high polarity cannot be used as a light oil mixed fuel. On the other hand, another previous study reported that by the use of light oil as a solvent, the homogeneous liquefied oil is obtained. However, the liquefied oil yield is low. Therefore, the authors thought that a mixed solvent of light oil and alkaline aqueous solution could be used to obtain low-polarity liquid fuel in high yield. This study aimed to clarify the liquefaction mechanism of woody biomass under mixed solvents. First, it was confirmed that the use of mixed solvents gave higher yields of low-polarity liquefied oil than the use of light oil solvents. Next, the reaction temperature was changed, and it was found that cellulose was liquefied at 250°C, lignin was decomposed at 300°C, and at 350°C, lignin decomposed products and liquefied oil combined to produce a residue. Finally, liquefaction was performed by changing the temperature holding time, and it was found that hydrogen produced by the water gas shift reaction was donated to the biomass decomposed product at the holding time of 60 min.

Aloe plants, which have medicinal properties, can be significantly valuable plants with high cash-ability. 2007, a new aloe species, Aloe djiboutiensis, was recorded in Djibouti, East Africa. This aloe species is used as a medicinal plant in Djibouti. However, the health benefits of the Aloe remain unclear since it has not been examined what kind of chemical components are contained. To evaluate the usability of the Aloe in Djibouti, further studies focused on bioactive components and their related biological activity was needed. In this study, the antioxidant activity of the aloe extracts was examined. For the next, screening of phenolic compounds of A. djiboutiensis was conducted by using LC-MS system. As a result, antioxidant activity was recognized in the extracts obtained from A. d., but the levels were not remarkable compared to reference materials. On the other hand, it was revealed that some bioactive compounds (Aloin A, Aloin B, and Isoaloeresin D) are contained in A. djiboutiensis. These would be attractive points for the cultivation and marketing of this aloe plant at Djibouti in the future.

One of the measures to enhance the water use efficiency or to prevent desertification in arid and semi-arid countries is to improve water holding capacity (water retention) of soils. This study focused on Spirulina, a planktonic blue-green unicellular microalgae classified as cyanobacteria. Since the Spirulina inhabits strongly alkaline water body which is generally seen in the tropics, the Spirulina is expected as a locally available soil amendments. Further, the Spirulina secretes Extracellular Polymeric Substances (EPS). The current study assessed the effect of the Spirulina and the EPS powders to improve the soil water holding capacity. Slight addition (0.5 to 5%) of the Spirulina and EPS powders to sandy soils resulted in a significant increase of the readily available water content for crop growth (RAWCC). The effect of the Spirulina on the RAWCC of the sandy soils was similar of that of the bentonite. Meanwhile, soils with textures of Silty Loam and Sandy Loam had little increases in the RAWCCs with those amendments. In addition, the RAWCCs of the soils treated with both Spirulina and EPS powders did not decrease significantly after heat treatment indicating the persistence of the effect. The results of the current study demonstrated the efficiency and its persistence of the Spirulina and the Spirulina-derived EPS to improve soil water holding capacity particularly in sandy soils.

Located in Central Asia, Kazakhstan is characterized as a semi-arid region which includes dry steppe land in the south. Agriculture carried out in this area is typically oasis farmland with water taken from local rivers used for irrigation. During the former Soviet Union, irrigation projects were widely carried out to expand agricultural land, and large-scale irrigation projects were created in several areas. However, many of these areas were abandoned since the collapse of the Soviet regime in 1991. In recent years, agricultural reforms have been carried out in Kazakhstan, and the privatization and fragmentation of agricultural land has progressed due to the free trade of agricultural land use rights. The study area of the Zharkent (Panfilov) Region is located on the border between Kazakhstan and China, is a semi-arid area and has been cultivating corn by irrigation from the Ili River and the Usek River for many years. Therefore, there are many abandoned agricultural lands because of salinization. However, this area is the start point of the railway and highway of China’s One Belt One Road (OBOR or Belt and Road Initiative, BRI) project to Europe, and corn production and exports are expected to flourish. In this study, we focus on the vulnerability of oasis agriculture and extract changes in agricultural land for about 30 years from 1989 to the present using Landsat series and Sentinel series and visualized them using RGB col-or combined techniques. The results show that agricultural land is disappeared or desertified at the Ili river basin and at the foot of the Zhongar-Alatau Mountains and that there are several years of fallow even in areas where agriculture is active. Using the Zharkent region in the irrigated alluvial fan of zhongar-Alatau Mountains of eastern Kazakhstan as an example, we classify the farm field changing using Landsat TM and Sentinel-2 satellite imagery and identify of vulnerability to the disappearance of oases farmland.

Rice consumption is increasing rapidly in Western African countries. However, this consumption is mostly covered by imports. In terms of food security, the governments of these countries have adopted agricultural policies and projects that strengthen the rice production sector. Numerous studies have suggested solutions for improving productivity and efficient farm management. However, these studies depended on field observations to grasp current farm conditions without considering farmers’ preferences, and perceptions. To achieve sustainable agricultural development, cooperation among local farmers is indispensable. Therefore, farmers’ perceptions should be considered in agricultural policymaking. This study attempts to evaluate local farmers’ preferences regarding important agricultural inputs for rice production, using the best-worst scaling method in Mauritania. The results indicate that most farmers recognize the importance of seeds and irrigation in rice production, but pesticides, fertilizers, and labor tend to be neglected. In addition, a hierarchical cluster analysis was applied to classify farmers into three clusters. The clusters 1, 2, and 3 emphasize irrigation, agricultural machinery, and seeds, respectively. The issues of low productivity, low quality, and inefficient labor use have been identified in the clusters 1, 2, and 3, respectively. Therefore, it is necessary to improve the technology and knowledge about the proper use of fertilizers and pesticides in the future, to encourage improvements in the yield and profits of farmers.

Irrigation shortage causes to use only 10% (4.65 million ha) of land of total cultivable area in Uzbekistan. Out of the area, cotton plantation is about 1.45 million ha. Hence, developing water-saving technology in cotton production is one of the crucial aims in Uzbek agriculture. One of main reasons of water shortage is improper water use by farmers. Mulch is defined as a coating material spread over the soil surface, and it helps to improve crop growth and yield as well as optimises water use efficiency. However, its effect on cotton production has not been studied very well in Uzbekistan. Field experiment was conducted in typical gray soil of Tashkent Province, Uzbekistan. Plastic mulching treatment (MT) and without plastic mulch treatment (control, CT) were tested in three replications in paired comparison design. In MT, polyethylene film was mulched on the brooklets before the first irrigation. The amount of water input by flush irrigation was measured with Thompson instrument. The average water input was two times less in MT (591 m³/ha) than in CT (1035 m³/ha) while cotton yield in MT (3.53 t/ha) was significantly larger than in CT (2.7 t/ha). Consequently, the water productivity (yield/water input) in MT (5.99 kg/m³ ) was significantly larger than in CT (2.60 kg/m³ ). Thus, the net profit in MT was 2765.8 USD/ha, which was 28% higher than in CT (2160 USD/ha). These results suggested that mulching soil surface with black polyethylene film in cotton cultivation contributes to saving more water in irrigation and leads to increase yield in Uzbekistan.

In Djibouti, as the amount of the fresh water is not large enough, deeper groundwater recharged in the volcanic aquifer has been developed and it is considered to be a new source of fresh water in most of the region of the country. Although some studies have been conducted to find out the volume, depth, quality and age of groundwater, the data is not still enough to construct a scheme of agricultural development using the deeper groundwater in large area of Djibouti. Therefore, the first purpose of this study is to estimate the original recharged area of the deeper groundwater of this country, using stable isotope (δD and δ¹⁸O) analysis, and secondary to calculate the age of groundwater, using radioactive isotope (³H and ¹⁴C) analysis. We have collected groundwater samples from 16 wells in 4 districts (Djibouti City, Arta, Ali-Sabieh, and Dikihil) in 2019. The results on δD and δ¹⁸O showed a possibility that the recharge areas were not simple in the complicated geological condition with lots of various faults even the location of wells is close. The concentration of ³H on the 6 samples was very low (under 0.3 T. U.), indicating that the age of the groundwater samples was older than 70 years.

The frequent droughts in recent years have made agricultural production unstable in Morocco. However, there are few studies on monitoring and assessment of water delivery management on lateral and tertiary canal level in the irrigation districts. Therefore, this study aimed to clarify water distribution in Beni Amir irrigation district, one of the large irrigation districts in Morocco and discuss the water-saving potential through improving water distribution. Water distribution records of all fields with areas were collected for 4 years from 2016 to 2019. Monthly precipitation data was collected for 48 years from the dam meteorological station. To clarify the water distribution in the study district, the amount of irrigation per unit area, the amount of water per irrigation, and the irrigation frequency by lateral and tertiary canals and fields were statistically analyzed during mid irrigation seasons (Apr. - Sep.). Monthly reference evapotranspiration was calculated by FAO-Penman Monteith method, and the balance of water supply and demand of the study area was analyzed. The results showed that large variations in amount of water allocation among lateral canals were observed in drought years while it was small in normal years. However, this does not mean that the upstream in the study area took more water. The different ratio of area under priority crops among the canals is a major reason for this. In addition, even in wet years, enough amount of water has not been supplied to meet the demand and this situation has not changed significantly over the past decade. Regarding the analysis on water-saving potential, 4.4 - 6.6 Mm³ of water could be saved by shortening the irrigation time unit from 1 hour to 30 or 15 minutes. This enhanced water distribution practice also contributes to improve the more equitable water distribution. Even if it is difficult to shorten the time unit for irrigation, water for distribution management could be saved by making the field area an integral multiple of 1.2 ha through merging and readjustment of fields.

Irrigation is essential for agricultural production in drylands, but improper water management such as over-irrigation and poor drainage has caused salinization. In India, in places where border irrigation (BI) is widely adapted, the high salinity of irrigation water and tendency of over-irrigation have promoted salinization, with areas of salt-affected soils extending to approximately 6.7 million ha. Water saving and improved drainage are effective in mitigating salinization; however, drip and/or sub-surface drainage are difficult for farmers to implement because of the high initial and maintenance costs. Therefore, it is necessary to introduce low-cost measures that farmers can easily implement.

Permanent skip furrow irrigation (PSFI) is an easy and low-cost water saving method that can save water by irrigating every alternate furrow instead of all furrows, with the irrigated furrow being fixed. Cut-soiler is a low-cost shallow sub-surface drainage technology that can make drain holes at 40 to 60 cm depth for burying the crop residue by pulling a tractor attachment. In this study, we evaluated water saving with PSFI under Cut-soiler construction.

A field experiment was conducted using mustard (October to April) during three dry seasons from 2018 to 2021. Test plots (30 m square) were set up without drainage (Control) and 2.5, 5.0, 7.5, 10.0 m construction intervals of shallow sub-surface drainage with the Cut-soiler. In each plot, BI, every furrow irrigation (EFI) and PSFI was applied with 10 m width respectively, and yield of mustard was measured. The total applied depths of EFI and PSFI were approximately 90% and 45% of BI, respectively. The results showed that the yield was highest in the plot using the Cut-soiler at 2.5 m interval under PSFI, 42% and 56% increases compared with Control in 2020 and 2021, respectively. This implied that there were no adverse effects on PSFI application due to Cut-soiler construction. In terms of irrigation method, the yield in PSFI decreased by 7% in both 2019 and 2020, but increased by 22% in 2021 compared with that in BI. Although PSFI saved around 50%, there was a possible risk of yield reduction. Therefore, by applying PSFI, supplementary irrigation should be conducted according to growth conditions.

Different water delivery performance indicators have been developed and widely used in irrigation districts over the world. Those indicators help users detect what the current water distribution problems are and where they are occurring. However, since these indicators are calculated only with water quantity, the relation between these indicators and farmers’ satisfaction with irrigation and yield is unclear. Therefore, this study attempts to examine the correlation between adequacy and farmers’ satisfaction with irrigation and yield in an irrigation district of the lower Nile Delta in Egypt. Adequacy was calculated with the amounts of water demand and supply. Using a questionnaire, 84 randomly selected farmers from upstream, midstream, and downstream of the branch canal were interviewed to collect data on farmers’ satisfaction with irrigation and yield. Then, to what extent adequacy of water supply can imply farmers’ satisfaction with irrigation water supply. The results showed that the adequacy was highly correlated with farmers’ satisfaction with water delivery in quantity and timing. Even though the adequacy in the upstream was evaluated as good, some upstream farmers were not satisfied with water delivery. This suggested inequity in water distribution within the upstream. In addition to the water quantity problem, one of the reasons for the low level of farmers’ satisfaction is that part of the irrigation was done at night. Farmers unanimously reported that the main reason for night irrigation was due to lack of water during the daytime. The lack of water during the daytime occurred in locations regardless of adequacy. Farmers’ satisfaction with yield was higher than water delivery. In the locations where the adequacy of water supply was poor, farmers’ satisfaction with yield was higher than water allocation. The water supply from the canal is not sufficient, but it is implied that groundwater and reuse of drainage water are used by farmers.

Irrigation is essential for crop cultivation in arid and semi-arid areas with limited rainfall and water resources. Efficient and effective use of water resources is required and saving irrigation water is important. Djibouti is a very dry region with annual rainfall of about 150 mm and an average annual temperature of 28.6°C. Due to such meteorological conditions, water resources depend mostly on groundwater, and this makes water extremely scarce. Therefore, water saving in agricultural sector is indispensable. This study aims at promoting effective and efficient use of irrigation water in Djibouti. The appropriate irrigation water amounts for tomato cultivation were estimated using CROPWAT provided by FAO and observed meteorological data at Ali Farren farm in Djibouti. The conditions required for calculating the amounts of irrigation water were medium loam soil based on the laboratory results of soil particle size test, and the tomato cultivation period from October to March according to the local farmers. The result showed that the average monthly reference evapotranspiration was 5.7 mm/day annually. Reference Evapotranspiration was maximum in July and August with 8.4 mm/day and minimum in December with 4.6 mm/day. The amount of irrigation water from October to March was about 476 mm which corresponds to the local tomato cultivation period.

This research aims at developing a water retention technology utilizing the capillary barrier (CB) concept for irrigated ground in drylands using local geo-materials. To increase the water retention by CB, where plants can grow and survive at the pre-pre-planting stage in dryland, clarifying the ground conditions, including the layers’ thicknesses ratio, grain size distributions, and watering method through experimental and numerical approaches is considered. The main findings include 1) The experiment of the CB with drip irrigation revealed that the volumetric water content (VWC) at a depth of 200 mm exceeded the target value of at least 0.1 on the third day when watering twice a week with 1000 mL per irrigation. 2) From the numerical analysis, supplying water twice a week was enough to maintain the VWC within a depth of 200 mm higher than the targeted value of 0.1. 3) To maintain at least a target value extending up to 200 mm depth by supplying 1000 mL water twice a week, an optimum configuration with an effective grain size ratio of 5.2, mean grain size ratio of 3.9, and a thicknesses ratio of 0.1 comprised of coarse and fine sandy soil layers was confirmed.

The construction of shallow subsurface drainage (SSD) using a cut-soiler contributes to the mitigation of salinization in the field owing to the increased drainage efficiency. In this study, we investigated the effect of SSD construction on the crop yield and fluctuations of the soil water and solute contents, which were monitored using dielectric moisture/salinity sensors in a test field in India. We investigated four spacings (2.5, 5.0, 7.5, and 10 m) in which SSD was constructed at a depth of 60 cm, in addition to plots without SSD. After the construction, pearl millet and mustard were cultivated in the rainy season (July-October) and dry season (October-April), respectively. The results of yield surveys show that higher crop yields were obtained after the construction of SSD. According to the monitoring data during pearl millet cultivation, the porewater electrical conductivity (ECp) of the soil in the plots with 2.5 and 7.5 m spacings was lower than that of the soil without SSD. With these spacings, the increased ECp only decreased after rainfall and irrigation. Our results confirm that SSD decreases the soil salinity and increases the crop yield in salinized farmland.

The large extent of sodic soils i.e. ~1.67 million hectares (M ha) and the problem of sub-surface soil sodicity restricting root growth reduce crop production in Indo-Gangetic Plain of Punjab and Haryana states. These states account for approximately 41 and 58% of the total food production and of the total 84-141 MT yr^-1 crop residue surplus production, respectively in India. This surplus production of cereal crops residue exhibits a typical problem of on-farm residue burning by the farmers and the rice residue management especially involves high cost, and time and energy intensive. To manage the twin problems of soil sub-surface sodicity and rice residue burning, ICAR-Central Soil Salinity Research Institute, Karnal and the Japan International Research Center for Agricultural Sciences (JIRCAS) have taken up a farmers’ field study to assess the comparative effect of gypsum and rice residue placement by Cut-soiler at different lateral intervals on amelioration of soil sub-surface sodicity and improvement in crop yield. The Cut-soiler assisted sub-surface application of gypsum, rice residue and gypsum + rice residue treatments consisted of, running the machine at 2.5, 5.0 and 10.0 m lateral spacing.

Placement of gypsum, rice straw residue and gypsum at 40 cm depth reduced subsurface sodicity (ESP) by 23.77, 14.92 and 5.95% at lateral distance of 0.30, 0.60 and 1.25 m, respectively. Decreasing lateral interval of Cut-soiler assisted subsurface placement, of gypsum, rice straw and gypsum + rice residue straw, from 10 to 5 and 2.5 m increased grain and biological yield of rice and wheat. The respective increase in rice and wheat yields were 16 and 15.5% in 2.5 m; 6% and 10.7% in 5.0 m spacing, respectively over control, but no significant increase in 10.0 m spacing. Therefore, closer spacing (2.5 m or less) seems promising for subsurface sodicity management in maiden study season.

Soil salinity is a global issue threatening land productivity, and estimates predict that 50% of all arable land will be impacted by salinity by 2050. Salt affected soils are important ecological entity in the landscape in most arid and semi-arid regions. In India these soils occupy nearly 6.7 million ha and represent a serious threat to country’s ability to increase food production to meet the expanding needs. India loses annually 16.84 million ton of farm production valued ~ $3.0 billion (USD) due to salt affected soils (Mandal et al., 2010; Sharma et al., 2015). The salinity management, especially in arid regions, needs an ‘on farm technology’ solution that can be adopted at individual farm/farmer level. Cut-soiler is a machine developed in Japan that use and manage surface scattered straw material, residue or remaining stems to construct residue filled shallow subsurface channels, while running on the field. The preferential drainage from these channels reduces soil salinity. In this background, Japan International Research Center for Agricultural Sciences (JIRCAS) and Indian Council of Agricultural Research - Central soil salinity research institute (ICAR-CSSRI) collaborative research project has been started to evaluate utility of Cut-soiler on salt removal and effect on crop yields in salt affected soils with the use of saline irrigation water. Three saline irrigation water treatments (EC_iw 4, 8, 12 dS m^-1) were applied in two soil types i.e saline and heavy textured. Mustard-pearl millet a major cropping system in hot, arid and saline regions of Northwest India was evaluated.

The preferential drainage through subsurface drains constructed by Cut-soiler reduced 32% salinity under Cut-soiler drainage over without Cut-soiler across the soil types and irrigation water salinity. The saline soil filled plots had higher ECe (Electrical Conductivity of extract of saturated paste of soil) (5.07 dS m^-1) than the heavy textured non-saline soils (1.39 dS m^-1). The reduction in soil salinity in Cut soiler plots was higher in saline soil i.e. ~11% and with 8 dS m^-1 salinity of irrigation water (20.4%) in October 2018 and this increase was higher with 12 dS m^-1 EC_iw in October 2019. The study found that saline irrigation water up to 8 dS m^-1 could be used without any salt loading. The lower salinity resulted in marginal increase in mustard yield in maiden season and 22.86% increase in pearl millet yield in successive season. Therefore, the Cut-soiler based preferential sub surface drainage may be a possible solution for salt removal from saline soils and preventing salt accumulation with application of saline irrigation water for sustainable crop production in salt affected areas having saline groundwater.

Worldwide, climate change is negatively impacting water resources and rice production. Rice crop in Uganda is grown on large and small-scale irrigation schemes with mainly traditional flooding, which overuses water compared to other irrigation practices. Additionally, rice production generally requires a lot of water during cultivation periods since its yield is strongly affected by water availability. The climate impacts on rice production range from unpredictable rainfall patterns, floods, landslides, to high temperature, which affects rice’s reproductive and development stages, thereby causing a decrease in plant height and root elongation. This study aims to analyze the climate change impacts more so temperature and precipitation on water availability and the application of water productivity open access remotely data (WaPOR data) to estimate the reference crop requirements (ETo). Long-term smoothed annual rainfall and precipitation data were downloaded from the climate knowledge portal. The ETo from 2010-2020 was calculated using the modified ETlook-WaPOR model. The results indicate that average temperatures have increased by 1.3°C since the 1960s. The western part of the country is warming faster than other regions with warming rate of 0.56°C/decade between 1950-2018. This will significantly affect water availability. The estimated ETo is found highest from December to march in all regions. Therefore, this study recommends: 1) improvement on the water storage, 2) promotion of water-use efficient techniques such as the Alternate Wetting and Drying technique for paddy, and drip irrigation for upland rice cultivation with farmer-led irrigation approach, 3) financing and promotion of in-situ weather, soil, water, and crop monitoring, and 4) Conduct training and knowledge transfer organic fertilizer production for farmers.

Water-saving irrigation is important in arid areas because of water shortages and the need to prevent salt accumulation. Subsurface irrigation is one of the most effective methods of water conservation, as well as the irrigation method using the negative pressure difference. In this study, the water characteristics of the string, i.e., the main material of a string irrigation system, were measured in the water absorption processes. Nylon and cotton strings with diameters of 6 and 3 mm, respectively, were used. The pot experiment of the subsurface string irrigation via the negative pressure difference for water saving was conducted under three conditions: cotton (6 mm), cotton (3 mm), and nylon (3 mm). The conditions of the hydraulic head were 5 and 10 cm. Furthermore, a numerical simulation of soil water distribution was conducted using Hydrus-2D. As a result, 1) water characteristic curve of each string was obtained. Meanwhile, the water retention capacities of nylon (3 mm) and cotton (3 mm) were high of pF 0.5–1.5. 2) The effectiveness of string irrigation was confirmed. The maximum water supply was estimated as 91.6 g/d per pot on average string (cotton: 6 mm, hydraulic head: 10 cm). The average water supplies of cotton (6 mm), nylon (3 mm), and cotton (3 mm) were 33.7, 32.9, and 25.9 cm³/d, respectively. 3) Because the soil water distribution could be expressed through a numerical study, calculations corresponding to the arrangement of strings could be performed. These results will contribute to water conservation in arid area irrigation.

We have presented a new scheme, “optimized irrigation”, in which irrigation depth is determined such that net income considering the price of water and weather forecasts during each interval is maximized using WASH_1D/2D which are numerical simulation models of water flow and solute transport in soils and crop growth. To evaluate whether the optimized irrigation is also able to restrict salinity stress and avoid salinization without any intentional leaching, we carried out an irrigation experiment. Mungbean (Vigna radiata L.) was grown in a greenhouse in Arid Land Research Center, Tottori University, using a drip irrigation system. Three treatments were established: 1) irrigated with fresh water using an automated irrigation system using two tensiometers installed below 10 cm (F), 2) same as above but irrigation water contained 1.5 g/L of NaCl (C), 3) irrigation depth was determined with the proposed scheme. 1.5 g/L NaCl solution was used for irrigation water (O). Each treatment had three replicates. After June 12, irrigation using the saline water started for treatments C and F. A 2.8 mm of leaching was carried out on July 2. Treatment F received the largest amount owing to the largest transpiration rate without any stresses. Treatment C received the lowest amount because of low transpiration rate due to salinity stress and unintentional leakage. We compared net income under producer price of 0.6 $/kg, common miscellaneous costs at 50 $/ha, water price of fresh water at 0.36 $/m³ and that of saline water 0.3 $/m³. Treatment F gained the highest gross income owing to the largest yield (835 kg/ha). Treatment C gained the lowest income and yield (448 kg/ha) while treatment O gained the highest net income owing to lower cost for water, revealing the effectiveness of the proposed scheme.

Many years have passed since the “Aral Sea Crisis” shocked the world. However, to this day, there is no coordinated approach to water resources among independent countries, and sloppy water management is still practiced. As soon as possible, we need to provide scientific evidence that will contribute to the realization of sustainable water resources management in the Aral Sea basin. In this study, we improved the physical model (SiBUC) of the Aral Sea basin by increasing the spatial resolution to 30 seconds, and by using various newly available data. Specifically, the use of Global Soil Wetness Project Phase3 (GSWP3) for forcing input data and the inflow into Lake Sarygamysh were newly considered. In addition, the parallelization of calculations in SiBUC and the saving of calculation area by creating basin masks have realized high-resolution calculations. As a result, we succeeded in visualizing the impact of climate change and land use change in the region. In addition, water storage and water balance of the Aral Sea were analyzed with good accuracy. However, considering the impact of Sarygamysh Lake, there is not enough runoff, so we need to check the water balance in each tributary area to find out what the problem is.

Kigali, the capital city of Rwanda, is affected by frequent floods during rainy seasons. Nyabugogo valley, the downtown of the capital is the typical impacted area with devastating damage. Among the mitigation measures given by several research, is rainwater harvesting (RWH). This study’s objective is to analyze floods in Nyabugogo valley using hydrological models, for estimation of the impact of RWH systems installation. Nyabugogo river discharge was calculated using SWAT model, for a period of 3 years 2011-2013. The iRIC Nays2Dflood Model was used to simulate and visualize the flooded area with the input data of the discharge simulated by SWAT model. The flood event reported on March 2^nd and 3^rd, 2020 was successfully simulated. The maximum water depth of 2.56 m and the maximum velocity of 1.38 m/s were detected at the confluence of Nyabugogo river and Mpazi drainage channel; and flood extended throughout the valley. The accuracy of the flood simulation was visually checked by comparison with the sentinel2 satellite images. In further steps, the RWH system installation will be simulated using a developed model precipitation by statistical analysis based on maximum rainfall return periods. Therefore, the changes in water depth and spatial extent of the flood before and after the system installation will be detected and quantified.

Floods in arid areas provide fertile soil and water resources, enabling agricultural production. Likewise, large floods will cause enormous human and economic damage. The Pech River, our study site, is a tributary of the Kunar River, which runs through eastern Afghanistan. The main source of the river discharge moisturizing the towns on the foothills is melted snow in the upper mountainous areas. Its maximum discharge changes depending on the amount of snowfall in winter. Therefore, it is necessary to predict the peak discharge in spring in advance and provide an appropriate flood warnings system. In this study, we tried to predict the peak discharge based on the fluctuation of snow cover area, temperature, and rainfall of the upper reaches of the Pech River. First, the boundary of the river catchment was identified based on the Digital Elevation Model (DEM) of 30 m mesh acquired by Advanced Land Observing Satellite (ALOS). Next, the Snow cover distribution data between 2008 and 2018 at weekly intervals was downloaded from the National Snow & Ice Data Center (NSIDC) database, and the catchment area was extracted. Daily observed temperature and precipitation data were expected as the parameter explaining the snow melting process in spring. We tried to reproduce the discharge of the Pech River using Artificial Neural Network (ANN). The temporal variation of the discharge was not linear to snow cover area, but ANN could reproduce it.

Soil salinity is one of the widespread environmental threats worldwide, especially in arid and semi-arid areas. Saline soils mainly occur due to inadequate irrigation and extensive agricultural activities, which account for many soil degradation processes. Advanced technologies such as remote sensing (RS) data have become an economically efficient tool for assessing, detecting, mapping, and monitoring saline areas along with their spatial and temporal variations. This study aims to develop a spatial database to evaluate salinization using RS and GIS (geographical information system). This research employed seven soil salinity indices (SI2, SI3, SI4, NSI, VSSI, NDSI, and NDVI) calculated from Landsat 8 Operational Land Imager (OLI) images. Classification of salinity class was conducted using a supervised algorithm built-in ArcGIS with the government soil salinity map as the training data. The indices utilizing the combination of visible and near-infrared reflectance (NIR) bands produce higher accuracy than those using only visible ones. Among all of the used indices, VSSI showed the highest accuracy.

Salt-affected soils are widespread in countries with arid and semiarid regions, and a decrease in agricultural production due to excessive salts is a very serious problem. In China, salt-affected soil amelioration with flue gas desulfurization gypsum (FGDG) has been performed. Otherwise, the accelerating urbanization has led to a large number of demolitions of infrastructures in China. Therefore, the need for the recycling and reuse of not only desulfurization gypsum but also waste concrete is a pressing issue. In this study, changes in physicochemical properties in the salt-affected soil amelioration with FGDG, cement fine powder (CFP) and waste concrete particle (WCP) were reported. Two high ESP soils in Yinchuan, China was used in the soil amelioration test. The CFP and WCPs in different particle diameters based on 1.0 wt% application rate of wet FGDG (W-FGDG) were added to the soil. Soil chemical properties (pH, EC, and ESP) before and after mixing with soil amendments were measured, and their properties were evaluated after 3 weeks and 6 weeks. Consequently, soil EC and ESP decreased drastically in all application tests, but soil pH in CFP and WCPs took a high value. And pH, EC, and ESP after 6 weeks took almost the same value immediately after amelioration. WCPs smaller than 2.0 mm could ameliorate a high ESP soil at a smaller amount of amendment compared to larger WCP. In addition, the increase in hydraulic conductivity due to waste concrete application could be confirmed. These results indicated the effectiveness of waste concrete as salt-affected soil amendments.

Land cover classification is vital for ecosystem assessment, desertification monitoring and vegetation inventorying. In recent years new technologies have emerged that can be used for land classification. One of these technologies are Unmanned Aerial Vehicles (UAV), that can take images applicable for remote sensing, and which allow collection of data in places that may be difficult to access. The study site is located in Ali Faren (42°49ʹ48ʺ E, 11°21ʹ43ʺ) at the Province of Arta, Djibouti. It is intended to use the 3D cloud point data generated from RGB cameras, which land cover features were classified using NDVI calculated from data obtained by multispectral cameras in the same study area. This classified point cloud was used for training and validating a deep learning model, which was applied for classifying cloud point datasets in three sites. It was found that there is a high accuracy when identifying “Ground” and “High vegetation” in the point cloud datasets with only RGB. However, there is a low degree of accuracy for identifying other classes, such as low vegetation. This can be attributed to the fact that shrubs and grasslands (3 Low vegetation, and 4 middle vegetations) are very scarce in the study area, so a higher emphasis on its identification is required.

Global warming is one of the most alarming environmental issues worldwide, disrupting the natural water cycle and exacerbating desertification. Proper understanding of the soil-atmosphere fluxes (mainly evaporation) is crucial. Most existing studies focus on the evaporation stages and the governing mechanisms. However, an environmental-friendly simple method to control the actual evaporation flux in arid regions is in great need to efficiently combat desertification. Through this paper, a simple design concept for a soil cover to maximize water conservation is proposed based on a series of 1-D column tests. It was found that using a coarse cover layer, the head gradient is oriented towards the bottom layer, disrupting the water supply to the surface and limiting the evaporation flux. While a fine cover induces a reversed head gradient oriented towards the cover layer, ejecting the water from the bottom to the top and resulting in a higher water loss. The proposed cover design includes two criteria: a) relative retention potential. b) relative cover thickness. The water storage capability can be maximized by applying a proper cover to minimize the criteria values.

Due to climate change, drylands worldwide have been suffering from extensive droughts and desertification. Finding innovative solutions requires a thorough understanding of the evaporation process dominant in such regions. The process is divided into three stages based on the actual evaporation rate. Previous studies confirmed the significance of Stage 2, the falling rate stage, in drylands. One of the process’s main controlling factors is the drying front, or the region separating the saturated and unsaturated zones. This paper studied the drying front’s spatial and temporal development during Stage 2 in sandy soil profiles that differ in the pore structure. The drying front was determined experimentally using 1-D homogenous drying column tests. Besides, a front depth determination method from the literature was adopted. Both methods showed an acceptable agreement with the front receding rate during Stage 2. Moreover, coarser sandy soils with narrow pore size distribution tend to have shallower front depths. However, during Stage 2, their drying front recedes faster into the soil profile. This study serves as a fundamental step towards evaluating the drying front during evaporation; It is believed to contribute to designing an environmental-friendly soil cover system used to maximize land water storage.

This study attempted to investigate the applicability of Mask-R-CNN to a farmlands detection in Djibouti using Sentinel-2. As training data, a total of 670 data were created, of which 580 were used for training and ninety were used for testing. Training was performed on RGB image and vegetation index (NDVI, NGRDI, NDWI) image from Sentinel-2 using Mask R-CNN. To compare a training model, SVM (Support Vector Machine) were also applied to the same Sentinel-2 images. In order to evaluate the performance, by defining the true positive (TP) as a truly detected object, the false positive (FN) as non-detected objects, the false positive (FP) as falsely detected objects, the precision and recall rate were calculated as performance indices. As a result, most of the indices obtained from the vegetation index image showed higher accuracy than that of the RGB image in both Mask R-CNN and SVM models. The recall rate of SVM is extremely low, which means that false positives are very frequent. Therefore, Mask R-CNN, which has low false positives is considered more useful than SVM the detection of farmlands. Due to the different distribution and location of farmland in urban and rural areas of Djibouti, the trained Mask R-CNN using vegetation index image was tested excluding urban areas with dense farmland. The recall rate increased from 6.5% to 19.6%, indicating that the accuracy of the model is expected to be improved by considering the locational characteristics of farmland.

The Tottori Sand Dunes, located along Japan’s Sanin Coast, are a UNESCO Global Geopark and a popular tourist attraction with millions of annual visitors. However, the tourism opportunities offered by them are hampered by such problems as severe meteorological conditions and vast, undulating landscapes. Constructing a virtual reality (VR) space might be one solution to these problems. Recently, a technique that combined unmanned aerial vehicles (UAVs or drones) and structure from motion (SfM) photogrammetry has been attracting attention for generating 3D models. The main objective of this paper is to construct a VR space of the Tottori Sand Dunes using 3D models generated from UAVs. Another objective is to examine optimal photography conditions and model generation conditions to create beautiful but small 3D models for the construction of a VR space. Two types of UAVs were used to acquire the image data. Metashape (Agisoft) was used as the SfM software for data processing. A cross-platform game engine called Unity (Unity Software Inc.) was used to construct the VR spaces. VIVE Cosmos (HTC) was employed as a head-mounted display (HMD) with controllers for the VR system. As the results, the VR space was successfully constructed in Unity using a 3D model generated by a combination of UAV techniques and SfM photogrammetry. The optimal photography and model generation conditions were determined and used to generate beautiful 3D models for the construction of a VR space.

This study aimed to clarify the meteorological characteristics of a farm at Dikhil in Djibouti and to evaluate the windbreak effect of hedgerows to plan and design a pilot farm in Ali Faren based on wind dynamics simulated using observed meteorological parameters. The analysis of meteorological observations at Dikhil farm showed that the east-northeast winds from October to April were twice as strong as the southerly winds from May to September. The computational fluid dynamics (CFD) analysis of the inflow from the east-northeast at a height of 3 m above the ground level confirmed that the windbreak effect of the hedgerows on the leeward side was effective in protecting the vegetable fields. The observations from the Ali Faren pilot farm indicated that the south-southeast prevailing winds blow throughout the year. The CFD analysis of the inflow from the south-southeast at a height of 3 m above the ground confirmed that the windbreak effect of several scenarios of hedgerow planning at the Ali Faren pilot farm was effective.

We are proposing a water-saving farming method for small-scale farmers using a solar-powered desalination system and purified freshwater. Desalination plants generally use reverse osmosis membranes, disinfection chemical materials, and consume large amounts of fossil fuels. The solar desalination system we have developed so far is a low-cost, repeatable system that uses the same vacuum heat-absorbing tubes and flat plate heat-absorbers used in solar water heaters. We consider that small-scale farmers are also less burdened by using solar heat, a renewable energy source. The result of calculating the energy conversion efficiency from the measurement of evaporation was 30 ~ 46%. Next, water-saving agriculture is so crucial for the efficient use of purified freshwater for agriculture. And the water-saving farming method was based on the stone mulch farming, laying bricks on top of root-prevention sheets and using pit tillage. The stone-mulch farming method reduces evaporation of water, and the root-prevention sheeting relatively reduces competition from weeds. Fertilizer and soil can be added to a locally tilled area to provide intensive nutrition. It also allows for continuous cultivation without removing stones and prevents soil drying and deterioration caused by full tillage. Although in Japan, the experiment of cultivating onions in the open fields using this farming method resulted in nearly double the harvest compared to the conventional method using a tiller. In the future, we will develop the technology for small-scale farmers, such as family farmers, can engage in production by also combining it with drip irrigation.

In high mountainous areas, clouds appear and there is occasionally heavy rain, but it flows out and dries up quickly. Vegetation is rare due to the dry and cold conditions. In this paper, we introduce a method for estimating mountainous weather using the example of abnormally cold and dry conditions in the Northern Japan Alps. We conducted a survey on foot from 17-20 Aug 2018, and could reasonably evaluate the local weather or climate in the high mountains by chance observations and various data of characteristic midsummer weather. An inversion layer was observed at about 2000 m on 17-18 Aug at the Wajima Aerological Observatory, and a temperature gap was discerned at 1350-2330 m. On 17 Aug, cold, dry and rather strong winds of 13.5 m/s from the north affected the 1500-3000 m layer during the day, and the minimum air temperature at Tarodaira (2330 m) was -0.8°C at night. On 18 Aug, minimum air temperature was -2.8°C with cold-dry weak winds at Tarodaira, and -4.0°C with frost at an elevation of 1900-2300 m in the Yakushisawa basin of the Kurobe headstream area. An analysis of sensible local climate is introduced as the first step toward an estimation method for mountainous climates.

This paper illustrates the situation of climate change and its impacts on the vulnerability of African pastoralists. Pastoralists in Africa face various climate change challenges that suppress their livelihoods and constrain their ability to adapt to fluctuations in the external environment. Although diverse scenarios of climate change impacts on African pastoralism have been proposed, climate-related changes will probably stimulate social and economic factors that intensify insecurity and conflicts, which undermine the adaptive capacity of pastoralists. Changes in climate extremes have been observed across the whole Nigeria over the last few decades. In this paper, climate change indicators of central Nigeria where a large population of pastoralists are settling in is analyzed to demonstrate the meteorological evidence of climate change. The perspectives of pastoralists on climate change impacts on their livelihoods are also introduced. Meteorological data demonstrate the great variations in duration and availability of rainfall over the last few decades. Increasing temperatures with higher irregularity are also observed. Interviewed pastoralists have a high awareness of the occurrence of climate change. Variation in rainfall and heat have various impacts on their livelihoods and increase their vulnerability as their adaptive capacity are getting more restrained.

The survey was conducted to compare the nutritional status of goats owned by nomads in Djibouti with that of goats owned by settled farmers, and to gain insights into the nutritional supply of natural forage plants in Djibouti. The survey was conducted on dairy farmers in Ambuli, near the capital, and nomads grazing around Ali-Sabieh in the second city. Dairy farmers own 2-3 ha of pasture and use shallow wells and 1000 L water storage tanks as water sources. Nomads moving distance is 10 km². In this survey, the survey items for goats were age, body length, chest circumference, body height, body weight, blood glucose level, and blood β-hydroxybutyric acid (BHBA) level. According to the results of this survey, the goats raised by nomads had a small body size and low weight for their age. However, the ratio of waist circumference to body weight was high, and it was inferred that the lumen was well developed for the physique. In addition, there was not much difference in blood glucose levels between nomadic and dairy farm animals, and it was presumed that the developing status of nomadic goats was poor. Furthermore, the BHBA levels of nomadic goats were high, suggesting that the organic acid produced in the lumen efficiently supplied energy. These results indicated that the goats bred by nomads were smaller but their nutritional status was not poorer than that of goats bred by dairy farmers.

In drylands, salt accumulation due to excessive irrigation and poor drainage negatively affects agricultural production. Water saving and drainage system improvement can effectively prevent salt accumulation. However, drip irrigation and subsurface drainage require initial and maintenance costs, making them difficult for farmers in developing countries.

As a low-cost and simple technique to improve drainage function, a new subsoil breaker called cut-soiler, which fills channels at 40-60 cm depth in soil with crop residues and functions as a filter, was developed in Japan. In a previous study, cut-soiler contributed to the improvement of fields with poor drainage in Japan. However, its salinity control benefits for drylands are unknown. Therefore, this study aimed to experimentally demonstrate cut-soiler on salt-affected soil in India.

A lysimeter experiment (2 m squares) was conducted to evaluate the saline soil remediation with and without cut-soiler plots during the dry and rainy seasons from October 2018 to August 2019. The calculated saturated EC (EC₍c₎) was continuously monitored by dielectric soil moisture sensors (5TE) to investigate its dynamics. The results showed that the EC₍c₎ peak with cut-soiler at 12 cm depth, after irrigation during the dry season, was 18.7% lower than that without cut-soiler. In the rainy season, the EC₍c₎ with cut-soiler at 50 cm depth decreased in response to rainfall and was 38.2% lower than that without cut-soiler. These results indicate that salts were dissolved by irrigation or rainfall and the infiltration water containing dissolved salts flowed through the outlet pipe of the cut-soiler.

The agriculture sector plays an essential role in the country’s economic development, such as food and funds for other sectors. This rule also applies to Djibouti, which locates in arid areas. On the other hand, underdeveloped agriculture can be a hotbed of poverty. Traditionally, self-sufficient pastoral has practiced in Djibouti. Still, the development of conventional pastoralism is no longer possible due to the limitation of natural resources such as grassland and the effects of population growth and climate change. Therefore, the government has promoted nomadic settlement. However, it is difficult to popularize settlement agriculture in Djibouti, where water resources are scarce. However, the number of farmers is steadily increasing. Thus, Djibouti’s agricultural sector is still slowly but steadily developing.

When considering the future development of Djibouti agriculture, clarifying the structure of agricultural will be necessary for policy formulation. Therefore, this study aims to sort out agro-pastoral areas and clarify the current structure of agriculture in the southern part of Djibouti by a case study of Ali Sabieh Region.

As a result, this study clarified Ali Sabieh Region’s structure of agriculture, mainly focusing on agro-pastoral areas. It used to be several farmhouses, have expanded to dozens of farmers, and the number of such areas is also increasing. Farmers have diverse backgrounds, but they manage less water and produce food. Therefore, increasing the number of such farmers may contribute to the improvement of poverty in rural Djibouti and, by extension, to the economic development of Djibouti.

In aquaponics, water is used multiple times between aquaculture and hydroponics facilities, so it is a food production technology that effectively uses water resources. In this study, we reused aquaponics drainage water to irrigate open fields. Open culture experiments were conducted in Mexico, and numerical experiments were also run to assess the risk of salt accumulation in an open field. In these open culture experiments, 18 mm of water was used in irrigation once a day. Electric conductivity (EC_w) was around 4 dS/m. The soil water and salinity in the root zone were monitored by capacitance sensors. After 120 days, we found sufficient condition in soil moisture for crops no remarkable increase in salinity and at the monitoring points. The numerical experiments were conducted under conditions where the amounts of irrigation were 9 and 18 mm/d, the frequency was once a day, the EC_w in the irrigation water was 4 and 8 dS/m, and evapotranspiration of 6.4 mm/d was measured on June 19, 2019, and then continued for 30 days. Moreover, we also simulated irrigation of the water at an EC_w of 4 dS/m at an irrigation rate of 0.375 mm/h for 24 hours (total amount, 9 mm/d) under the same climate conditions of other cases. From these simulations, although salts accumulated at the edge of the wet zone formed by irrigation, we could observe that the saline concentration in the root zone was well maintained without any increase. We concluded that it is possible to use aquaponics drainage water of 4 dS/m as irrigation water for open culture if a sufficient amount of water is prepared or the scheduling of irrigation was planned effective for mitigating salt accumulation.

Salt accumulation in fields appears partially in a very thin surface layer of the soil at an early stage of its occurrence. At this stage, removing the salts is only efficient in the parts where salt has accumulated. The surface suction leaching method (SSLM) removes the partially accumulated salts in this stage. SSLM equipment consists of three parts: water supply, drainage, and insert parts. The insert part is a disc-shaped container with a stainless guide that is inserted into the soil and connected to the water supply part for leaching and the drainage part for collecting water from the soil water. Through the insert part, the SSLM collects soil salts by alternately supplying leaching water and sucking soil water until a predetermined salt removal rate is achieved. In this study, we conducted 12 cases of numerical experiments that varied the water supply and suction times. We clarified the relationships between the water supply and suction times and their optimum combination that minimizes the amount of leaching water required to achieve the objective salt removal rate and reached the following conclusions: 1) shortening the water supply time and lengthening the suction time effectively reduce the amount of leaching water; 2) excessive suction time increased the amount of required leaching water; 3) the optimum combination of the water supply and suction times under the experimental conditions was 15 seconds for the water supply and 600 seconds for the water suction; 4) we must determine an optimal suction time that is suitable for the water supply times in the SSLM.

Recent rapid economic growth of Africa has been attracting enterprises in the world as a great opportunity of their business extension. Japanese government has also put emphasis on business partnership with African countries rather than regarding as a target of development assistance. The change of measure is reflected in trend of the main topics of a series of Tokyo International Conference on African Development (TICAD), held periodically under auspice of Japanese Government. This study aims to investigate trends in the extension of business of Japanese enterprises under the change of the measure. A set of the lists of Japanese enterprises having business on Africa as of 2013, 2014, 2015, 2017 and 2019 was conducted to analyses of the changes by countries and business categories. In the recent two years, business extension of Japanese companies showed rapid growth especially automobile related ones, integrating trading company (Sogo Shosha) and financial services. South Africa and Egypt were the focal points of the business of Japanese enterprises and their local branches but since 2017, additional focal points such as Kenya, Morocco and Nigeria have been emerging.

The aim of this study is to verify the nomadic perceptions that based on a view of nature environments of the people who use the grassland. In response to the question of what kind of grassland in good condition, 18 households chose that there were many plant species and 15 households chose that there was a large amount of plants. All nomadic pastoralists hoped to restore a degraded grassland basically. In response to the question of how to restore grasslands from degraded condition, 16 households chose that they would restrict and 13 households chose that abandonment. Nomadic pastoralists did not select restoration by forestation, seedling, fertilization and watering. It seems to consider these methods are agricultural acts that not match in their traditional sense of value. Nomadic pastoralists were thinking that if the grasslands in degraded condition were abandoned the number of species and the amount of grass would increase. However, artificial environmental changes that greatly exceed the resilience of nature environments are carried out, then the grasslands will not recover naturally beyond the rules of thumb of nomadic pastoralists. Some nomadic pastoralists were concerned about the financial burden. It means that the development of inexpensive and effective restoration methods for abandoned agricultural land is an urgent issue for nomadic pastoralists. In this study, we were able to clarify some of the values of nomadic pastoralists for grasslands. In order to consider sustainable grassland usage from multiple perspectives, it will be necessary to continue discussions, including the values of stakeholders who are using agricultural land.

This study used US military reconnaissance satellite images to identify the locations of lost pit-type yaodong in the Luoyang basin. A total of 7,668 data points were obtained by estimating the positions of the courtyards of pit-type yaodong. Pit-type yaodong were found in the west, north, and east but were rarely observed in the southern part of the basin. In the eastern and western parts of the basin their density tended to be high. I examined the factors that influence the distribution of pit-type yaodong by analyzing the relationship between the pit-type yaodong locations and the altitude and topography, using GIS. By estimating the number, distribution, range, and locations of pit-type yaodong, this study provides new geographical knowledge of architectural and cultural aspects of yaodong in the Loess Plateau.

Agriculture plays a major role in the economy of the Kyrgyz Republic, a small, landlocked, mountainous country in Central Asia. The National Development Strategy of the Kyrgyz Republic is focused on agroindustry as a priority sector for the development of the economy. Due to the comprehensive, innovative agrarian reforms with minimum government intervention, the agricultural recovery in the early 2000s was driven entirely by growth in the private sector, with increasing output from peasant farms. In this study, we analyze the emerging peasant farmer entrepreneurs as the prospective leaders of sustainable agriculture in the Kyrgyz Republic. Statistical data and empirical results from field surveys were used to analyze the potential capacity of individual entrepreneurs in the sector. Our findings indicate a beneficial impact of entrepreneurs on the promotion of sustainable agriculture and the increasing value of the “Made in Kyrgyz” label in regional markets.

Uzbekistan is a developing country in Central Asia with an area of 447,400 km². Most of the agricultural production in Uzbekistan involves irrigated agriculture. Arable land accounts for 4.4 million ha, which is approximately 10% of Uzbekistan’s total area. The role of agriculture is vital to the national economy, particularly in terms of food security and employment, and provides an important income source for 4.7 million households that operate dehkan (small-scale) farms in rural and disproportionately poor communities. The current study was carried out in 13 villages in the Samarkand region to identify the current conditions and challenges of local dehkan grape producers by measuring income, consumption expenditure and food security, and paying attention to heterogeneity among farmers. The results of the current research revealed that viticulture contributed to 84.1% of total dehkan income and played a significant role in household welfare. We divided respondents into four groups by farm size (1^st group: < 0.36 ha; 2^nd group: 0.36-0.50 ha; 3^rd group: 0.51-0.70 ha; and 4^th group: > 0.70 ha), and found differences among them in various household characteristics, including the importance of viticulture income. In addition, several challenges were identified, including a lack of infrastructure, prevalence of pests and diseases, high prices of inputs, water shortages, low prices of grapes and raisins, lack of capital, limited access to markets, and lack of skills. These findings have important implications for viniculture development and further increases in dehkan income and well-being.

Agriculture plays an important role in Uzbekistan’s economic development. Most of the grapes grown in Uzbekistan are exported as table grapes or raisins, and production of raisins has gradually increased to the point where they are now one of Uzbekistan’s main agricultural exports. Even though Uzbekistan is now one of the world’s top exporters of raisins by volume, its average export price for raisins has remained very low compared with average global prices. Obtaining average global prices for their product would provide better opportunities for agribusiness participants, and in particular would indirectly increase the incomes of small farmers. Therefore, the aim of this study was to develop a sustainable export strategy for agribusinesses in Uzbekistan by identifying the factors responsible for the low prices obtained for exported raisins. Because the export strategy is subject to multi-criteria decision-making, the analytic hierarchy process model was used. All of the factors influencing the final price of raisins were grouped into six categories and the five main commercial raisin varieties were chosen as alternatives. The results showed that the most important factors in determining prices were the quality of the product, the availability of a quality control laboratory, processing facilities and equipment, and certification, while the best variety was the golden raisin. Focusing on these factors would increase export prices by more than 50 percent.

Agritourism can enhance rural development and is a useful alternative activity to increase farm incomes. As a result of rapid growth worldwide, agritourism has become one of the most significant supplementary income sources for farmers. This study examines the development of agritourism in the Samarkand region of Uzbekistan, using scientific studies and statistical data, which indicate that there are great opportunities for agritourism activities. Increasing the economic potential of the rural areas by introducing innovative activities on Samarkand region’s medium-sized farms (fermers) and ensuring sustainable development is essential. Samarkand has extremely favorable conditions for many forms of tourism, especially agritourism. Thus, the main purpose of this study is to examine the current situation and identify issues influencing the sustainable development of agritourism in Samarkand. Currently, 10 fermers in Samarkand engage in agritourism. We surveyed all 10 of these, and 100 randomly selected fermers in Samarkand that do not carry out agritourism activities. Based on this data collection and analysis using chi-square and t tests, we found significant socioeconomic differences among agritourism and ‘nonagritourism’ fermers. The results also indicated that agritourism is not popular among fermers in Samarkand. Finally, we investigated the general characteristics of fermers in the region, the current state of agritourism, the economic situation of fermers, and challenges in the development of agritourism.