Recent years, flood disasters have become rampant due to climate change. For the risk mitigation, building up a hydrological run-off model which can be used accurately and quickly helps communities prepare effective disaster prevention measures. Tank Model is a hydrological run-off model proposed in Japan. On one hand, its calculation is relatively simple. On the other hand, many unknown parameters have to be identified. Thus, the more random number it generates at a time, the more it takes time for calibration. This research examines the optimal method of identifying the unknown parameters by Monte Carlo method, considering the improvement of efficiency for practical use. Montel Carlo method can generate the massive number of random samples and help us select the best combinations of unknown parameters. Among the generated random numbers, the optimal parameters are searched which can fit to the actual measured values with the minimal number of samples. This research examines how many random numbers need to be generated at minimum to obtain the optimal parameters. The number (N) of random samples were seven kinds of 100, 1,000, 10,000, 100,000, 1,000,000, 10,000,000 and 100,000,000. Every time random samples generated by Montel Carlo method, the maximum and minimum numbers of each unknown parameter among the five best combinations were applied for the retrieval range of the next simulation. In this way, the simulation was repeated ten times for each kind of sample number. As the result, the watershed with simple land-use could obtain the optimal parameter with fewer samples (N = 1,000) than the watershed with complex land-use type (N = 1,000,000). With these sample numbers, the prediction accuracy for both watersheds were high. It is considered that the complex land-use watershed had lower accuracy rate because the water runoff was influenced by the underdrainage facilities.

Combined pollution in farmland soil is a recognized issue in Japan. The measurement of combined pollution has been discussed because the interaction between heavy metals is complex. To date, soil dressing has been the primary method employed to tackle this problem. The objective of this study is to clarify how the percolation patterns of polluted subsoil affect Cu and Cd uptake, and the growth and yield of paddy rice plants. We prepared six stratified paddy-field models to test growth with plowsole and subsoil in open and closed percolation patterns. Each model consisted of a 12.5-cm-thick plowed layer and an upper plowsole made of a non-polluted soil dressing and underlying polluted plowsole and subsoil. Three soils with three levels of Cu contaminations (100, 250, and 500 mg Cu kg^-1) were prepared by adding a Cu solution to Cd-contaminated paddy-field soils (1.7 mg Cd kg^-1). Three of the six models were open systems, and the other three were closed systems. During the tests, a constant water-ponding system was adopted. As a result, the polluted plowsole and subsoil became oxidized in the open system and reduced in the closed system. The Cu and Cd concentrations in the rice grains were 5% higher in the open models than in the closed models, regardless of the original Cu concentrations in the polluted soils. Interestingly, the Cd concentrations in the grains had an inverse relationship with the Cu concentrations. No significant difference was observed in the growth and yield of the rice plants among the models. We concluded that the Cu and Cd concentrations in rice plants were affected by the percolation patterns of polluted plowsole and subsoil, even though they were covered with non-polluted soil-dressing layers.

In recent years, Japan has been receiving heavy rainfall, and the flooding of irrigation ponds is a major concern. The irrigation ponds in the Tamatsu district in Tottori, Japan, are small and overflow easily during heavy rainfall. Pre-releasing water from these ponds was suggested as a simple, safe, and low-cost solution. However, local governments have prepared no clear guidelines or instructions on the amount of water that should be pre- released or regarding the desired water level after pre-release. Currently, the water volume that is pre-released from the ponds depends entirely on the pond manager’s experience. To mitigate this situation, we first observed the water level and discharge of the irrigation ponds and collected rainfall data from the nearest meteorological station. We then assessed the water storage operations of pond managers at three irrigation ponds in the Tamatsu district in 2018. Subsequently, we prepared the height-volume curve (H-V curve) of each pond by level survey and 3D image analysis, and a cumulative water demand curve based on the volume of water released from each pond during no rainfall periods. Considering the cumulative water demand curve and the height of the intake tap of each pond, we prepared water storage operation curves for the irrigation ponds. This will assist pond managers to determine the appropriate water level reduction during heavy rainfall events without causing an irrigation water shortage. We confirmed the extent to which the pond management curve could cope with rainfall. Using the developed water storage operation curve, managers can easily understand the drop of the water level in the pond. Moreover, the curves are easily constructed from the information on the beneficial area, precipitation, water level fluctuations of the irrigation pond during dry days, and the H-V curves of ponds. Finally, the effectiveness of the water storage operation curve is evaluated for different rainfall events.

Rice (Oryza sativa L.) is an important target crop for water use reduction because of its greater input water requirement than other crops. The pot experiment was conducted to evaluate the effect of two different levels [full irrigation and deficit irrigation (50% Plant Available Moisture)] on the growth, yield, chlorophyll content and water use efficiency of improved rice lines. Preliminary test for drought tolerance for the one hundred improved rice lines was conducted and screened under pot experiments in the dry season of 2018. After screening this test, the selected rice lines were grown at two different water levels in the screen house during the rainy season of 2019. Each experiment was assigned as a randomized complete block design with three replications at Yezin Agricultural University. The result of the preliminary test in 2018 found that among the one hundred YAU improved rice lines, seven lines were tolerant to deficit irrigation. In 2019, all selected rice lines were also tolerant to deficit irrigation. These lines also produced the best performance of the plant growth, the grain yield and yield component characters when compared with the checked variety. However, deficit irrigation for all selected lines reduced these characters when compared with full irrigation. The five rice lines under deficit irrigation produced the high chlorophyll content and water use efficiency when compared with full irrigation. Thus, it can be concluded that the highest drought- tolerant rice lines would be useful for plant breeding program.

The shortage of agricultural water in the Sangker River basin of Cambodia is becoming a severe problem, and the river flow seems to have decreased. The present study assesses the excess and deficiency of irrigation water resources in this river basin for agricultural production. The Soil and Water Assessment Tool (SWAT) is used to analyze the water balance at the main headwork in this river from 2014 to 2018. SWAT was used to estimate the available volume of stream water at the ungauged point of the Kang Hot headwork, and the model performance was evaluated at a gauged point downstream by the Nash–Sutcliffe efficiency (NSE). The model was calibrated manually and automatically by using data from 2007 to 2013. Furthermore, the flow rates in the two main irrigation canals were measured from June 2018 to October 2019 to obtain the actual irrigation water supply, and the evaluation was made by checking the difference between supplied water volume and irrigation water demand. The model output showed good agreement between observed and simulated monthly streamflow during the validation period (NSE = 0.69, RSR = 0.55). From the results of water balance analysis, water shortage rates exceeding 20% of the monthly water requirement occurred mostly between April and June from 2014 to 2017. Furthermore, there was excess water supply in 2018 because of abundant river flow that year. The actual irrigation water supply during the study period showed rates of water shortage of 52% and 41% in the left and right main canals, respectively, at the headwork. This study provides new insights for field technicians to consider irrigation planning for present and future water resources management and development for sustainable irrigation agriculture.

Whiteflies (Bemisia tabaci (Gennadius)) are important vectors of diseases of tomato crop production. Outbreaks of whiteflies can cause decreased productivity and transmit pathogens. The purposes of this study were to compare the degree of white fly infestation in two varieties of tomatoes, Shiny Queen and Ninmanee, and to investigate whitefly population responses to weather-related environmental parameters. The study was conducted in a green house. Whitefly population was counted every two days on three positions of the plant; the upper part, middle part and lower part. The results indicated that the Shiny Queen variety was infected with significantly higher numbers of white fly than was the Ninmanee variety. Whitefly numbers observed on Shiny Queen variety were significantly related to temperature, relative humidity, solar radiation and dew point. A mathematical model was developed to predict the relationship of environmental conditions to white fly population.

Rolling/crimping technology for terminating cover crops is essential to ensure that the rolled plant residue benefits both soil and succeeding cash crops. Cambodia has also adopted this technology, but it is still at the initial stage due to limited rolling services. The objectives of this study were to compare different roller-crimpers with the Oggun-mounted USDA roller-crimper in terminating sunn hemp (Crotalaria juncea L.) and to determine their effects on soil strength and soil moisture. The experiment was conducted in Rattanak Mondul, Battambang province in the wet season of 2019, using a randomized complete block design with three treatments having four replicates, each of which was 14 m x 34 m and spaced 5 m. The treatments consisted of (i) a USDA roller-crimper, mounted on 19-hp Oggun tractor, (ii) a Cambodian made roller-crimper with elliptic bars, and (iii) a disc-plow, both pulled by a 75-hp tractor. Plant height and biomass before rolling; soil strength at 0-10 and 10-20 cm depths before and after rolling; field operations; and soil volumetric moisture content (VMC) evaluated on the day of rolling, and then one, two, and three weeks after rolling, along with termination rate were analyzed. The results show that the height and biomass of sunn hemp were not significantly different among the treatments, being 164 cm and 2.57 t ha^-1. In Oggun crimping, speed and field efficiency were lowest, being 3.5 km h^-1 and 0.8 ha h^-1, but fuel use was highest. Under plow-based management, soil compaction was slightly higher and termination rate was more efficient, when compared to other treatments. Significant difference was not observed for VMC between the equipment used. However, crimping can be beneficial for cover crop termination, compared with disking that may have long-term effects on the soil.

Loss on ignition (LOI) method is widely regarded as a quick, inexpensive method for evaluating organic matter characteristics in terrestrial soils and littoral sediments. Previous studies examined the LOI method alone to evaluate the state of organic matter, finding that changes in the state of organic matter in littoral sediments could be represented by LOI method-based indices related to combustion temperature: (LOI₃₀₀−LOI₂₀₀)/LOI₆₀₀ and LOI₃₀₀/LOI₆₀₀. However, these new indices have not been applied to agricultural soils. In this study, laboratory experiments were conducted to examine the validity of our proposed indices for evaluating the state of organic matter in agricultural soils. Paddy soil, Andosol, and cow manure compost were allowed to decompose over three months. Measurements of pH, redox potential (ORP), and weight LOI at 200, 300, and 600°C were measured at one and three months after the experiments started. Temporal decreases in ORP were observed, highlighting the decomposition of organic matter present in each material. The (LOI₃₀₀−LOI₂₀₀)/LOI₆₀₀ metric changed over time for all materials, whereas the LOI300/LOI600 metric was almost constant. We concluded that (LOI₃₀₀−LOI₂₀₀)/LOI₆₀₀ can represent changes in the state of organic matter in agricultural soils. Furthermore, we discovered that LOI₂₀₀/LOI₆₀₀ can represent changes in the state of organic matter with reasonable accuracy, rather than the more complicated (LOI₃₀₀−LOI₂₀₀)/LOI₆₀₀. This finding should make LOI measurements easier and more affordable.

Cambodia shifted from an agrarian-based to a service- and production-based economy through its fast-economic growth. However, agriculture is still a backbone of the Cambodian economy because 80 percent of the population lives in rural areas, and around 37 percent of the total workforce remains directly engaged in the agricultural sector. Even though the Royal Government of Cambodia (RGC) considered the enhancement of the agricultural sector as a high priority in its national development agenda for 2014 to 2018, Cambodia remains a net vegetable importer. Approximately USD 200 million of vegetable products are imported informally from Thailand and Vietnam each year. Several research studies have been conducted to identify farmers’ constraints. However, challenges faced by small-scale vegetable farmers have yet to be clearly characterized. This research aimed to identify the farming practices and challenges of small-scale vegetable farmers in Cambodia. There were 40 households, selected by homogeneous purposive sampling method, surveyed from the Kandal, Kampong Chhnang and Battambang Provinces. The results of the study are divided into three parts, with the first component focused on farming practices. There were 12 types of vegetables that were identified as being grown in the studied areas. However, only 5 types of vegetables were commonly grown by farmers. Chinese mustard (55%) was the most popular vegetable being grown in the areas, followed by green mustard (50%), pak choi (45%), leafy mustard (37.5%) and Chinese kale (27.5%). Due to small production size, almost all interviewed farmers harvested their products by sickle, knife, and/or scissors, and manual harvest is still in practice by some farmers. Post-harvest activities such as grading, sorting and cleaning products after harvesting and before selling are not commonly practiced by farmers. Second, the majority of vegetable products are sold to collectors; a small quantity of remaining products is sold to retailers, farmers’ groups/cooperatives and direct consumers in the areas. Third, the study revealed three main challenges faced by farmers. Insect pests and disease infestation (87.5%) was the most prominent issue of vegetable farmers, followed by climate change (e.g. flooding, drought) (77.5%). Low selling price and considerable fluctuation in prices were equally problematic (both 57.5%). Other notable issues included post-harvest losses especially in peak seasons of oversupply (45%), lack of power in the market chain (42.5%), and lack of pest control information (40%), while lack of information about market prices (37.5%) and poor market information systems (37.5%) were the minor issues in vegetable production.

This study was carried out to evaluate the feeds and feeding practices of dairy cattle farming in Yangon, Mandalay and Sagaing regions. The secondary data and questionnaires were assessed from 60 farmers of 60 households in the study area and made discussion with them. According to the findings of this study, zero grazing was the main production practices used by smallholder dairy farmers in the study area. Most of farmers used locally available feed resources such as cut and carry grass, forage crops, crop residue after harvesting and local feedstuffs. Common feedstuff used by dairy farmers in the studied areas are broken rice, rice bran, wheat bran, beer cake, bean cake, oil cakes, cotton seed cake, sorghum, yellow corn, soybean meal, mineral block, and sugar syrup. Feeding input among the farmers in the studied areas is similar. However, the availability and quality of these resources are varied, but farmers are properly selected and combined according to their nutritional characteristics, adequate and productive diets had been provided all year round for sustainable production and productivity. There are generally two feeding practices: compound cattle feeding and home-mixed feeding in the studied areas. Among the respondents, 84.77% preferred to use compounded cattle feeding and others 15.23% used home- mixed feeding. Most of the farmers in the study area used natural mating methods than artificial insemination method (AI). Over 90% of the respondents had knowledge on the signs for oestrus detection. The average 7.45liter and 6.48liter of milk per cow per day was recorded in wet and dry season from the study area. Seventy three percent of dairy farmers used concentrate to their animals based on milk production.

Salinity from spraying may be important with crop cultivation and pasture for grazing. Soil guidelines can indicate salinity build up in soil. Effects on cultivated crops and soil cumulative contaminant loading limit trigger values are generally available for salinity, heavy metals and pesticides (kg/ha) for long-term application of irrigation water to soil. In addition, metal levels in meat from livestock and fowl species can be compared against food standard guidelines. The air quality guidelines of the World Health Organization (WHO), European Commission (EC) and United States Environmental Protection Agency (USEPA) are based on studies of health effects undertaken globally. However, little detail exists on effects of air particulates on terrestrial animals. Animals breathe air and may ingest deposited particles on soil surface or via ingestion of grass or other plants. Soil contamination guidelines are well developed for the ecological health case but may require extensive assessment for soil and the native/wild species that are not characterized. The German metal deposition guidelines (TA Luft) are useful in this case. In contrast to native/wild species, domestic animal effects from soil contamination and particularly pasture grazing by cattle, sheep, pigs and fowl are well understood. Such guidelines provide a basis for developing site specific criteria for spray deposition to farm land. Particle dispersion and deposition for prediction of environmental effects from spraying using risk assessment can be developed. Guidelines for air particulates and fall out may be relevant to assess if spraying is significant to humans or animals but limitations of guidelines for contaminants can occur. Risk-based assessment for environmental management of spray dispersion and deposition of agricultural wastewater can be undertaken as such contaminants may be significant if they are dispersed at sufficiently high concentrations.

This study was to evaluate the growth performance of goats fed different proportions of sorghum silage and Napier grass. A total of fifteen local male goats were divided into five groups on the basis of Completely Randomized Design (CRD). The dietary treatments were: T₁ (100% Napier grass); T₂ (75% Napier grass + 25% sorghum silage), T₃ (50% Napier grass + 50% sorghum silage); T₄ (25% Napier grass + 75% sorghum silage); and T₅ (100% sorghum silage).The experiment ran for 98 days. The average daily nutrient intake of dry matter, crude protein, organic matter, neutral detergent fibre, acid detergent fibre and cumulative live weight gain of the goats fed on T₁, T₂, T₃, T₄ and T₅ diets were not significantly different (p > 0.05) from each other throughout the experimental period. Based on these results, regardless of the inclusion of Napier grass in the diet, 100% sorghum silage could be favourable feed for local goat in Myanmar especially dry zone area where goats are populated and sorghum is available in planting.

The problems of neglected bamboo forest have been actualized in association with the aging of the people owning bamboo forest in recent years in Japan. Then it becomes imperative to establish the methods of effective utilization of the bamboo. Some bamboo has enough tensile strength as construction material, and studies and experiments on bamboo have been increasing gradually. The purposes of authors are to make short fiber of bamboo (“BF” for short) from Moso- bamboo, one of most popular bamboo in Japan, by ourselves, and to develop the concrete for pavement which matrix are reinforced with BF. A cross- linked effect between concrete surface on crack by BF had been expected as same as other kinds of short fibers. The purpose of this paper is to confirm the reinforcement effect by BF, and cement mortar was the object in order to simplify the experiments, in which the basic properties were investigated. The experiment factors are the amount of BF, water cement ratio, fiber length and distribution method of BF. These influence on compressive strength, bending strength and bending toughness was investigated experimentally. As the results, the followings were obtained. The strength does not increase only by a cross-linked effect by BF. The coefficient of toughness can be improved greatly by BF, and this effect is shown even in little quantity of fiber. Influence of water cement ratio on the toughness improvement is small. In case of random mixing of BF, each strength become lower without depending on fiber length, toughness coefficient can be improved. In case of spreading of BF, the strength and toughness coefficient can be improved even in little quantity of fiber.

This study aims to explore the relationship between home gardens’ sizes and species richness of horticultural crops and to study the distribution of mango varieties in the selected area. Sixty home gardens were studied from September, 2018 to October, 2019 in Nay Pyi Taw Union Territory, Myanmar. Drone was used to generate geographical information. Coordinate points of each mango variety was collected. Information on compound dimensions and crop plants namely local names, growth stages, numbers of individual, leaf attitudes and characters were collected. Shannon-Wiener’ index was employed to determine species richness. Distribution maps of mango varieties were developed. The compound areas could be classified into three classes as small, medium and large; were not correlated with species richness of all horticultural crops, but there had significant correlation with richness of mango varieties (p = 0.01, r = 0.32). Potential area for home garden development was highest in large gardens (41%) followed by medium (16%) and small (9%). Out of total 480 species, richness was highest in ornamentals (46%) followed by vegetables (10%), fruits (8%), shade-trees (8%), medicinal-plants (6%), spices (3%) and unidentified species (20%). Among fruit trees, mango was the most dominant species and 90% of home gardens were growing a total 361 plants (young 37% and adult 63%) of 15 local varieties namely Ma Chit Su (39%), Sein Ta Lone (24%), Sein Sar Thee (20%), Yin Kwe (9%), Ma Naw Nwe (3%), Waso, Padamyar Nga Mauk, Mya Kyauk and 4 unknown varieties (1% each) and Wet Ta Kaut, Pan Swae and Pyo Ta Ngone (0.3% respectively). Three types of leaf attitude and 8 different leaf characters of mango varieties were identified. Diversity index of total species was 1.57 and 1.40 for mango varieties. It was concluded that species distribution was sufficient; however, there is remaining available space to extend home gardening in the study area.

National parks play important roles in the conservation of biodiversity, environmental protection, and provision of resources for local livelihoods. This research aims at examining the effect of forest cover change in Phnom Kulen National Park (PKNP) on water quality and downstream local livelihoods along the Siem Reap river. Forest cover change in the park was collected from the United States Geological Survey from 2000 to 2016 through the Multi-Temporal Satellite Imagery (MTSI). The study used livelihood approach to interview with 120 households and four key-informants to elicit local perceptions on effect of forest lost on their livelihoods. The research found the forest cover in PKNP decreased by 22% from 2000 to 2016. The loss of forest cover has affected downstream local people whose daily livelihoods depend on Siem Reap River. Scores on local perceptions were low. Livelihood capital were performed low; only 0.48 score on natural capital, 0.44 score on human, and 0.24 score on financial capital, in which correspondent perceived their livelihood did depend significantly on those capitals. However, we found that the physical and social capitals were not significantly affected by the forest cover change because forest clearing created stable access to infrastructure and social network. As forest cover declined impacted on the declined of crop production, fish availability, water quality and access to clean water. As local needs to adopt new skills for living, human and financial capitals were low. The study confirmed the forest cover change at national park had a serious impact on the downstream local livelihoods.

Fertilizers play an important role in the maintenance of soil fertility for rice production. The correct application of fertilizers can alleviate declining soil fertility. To improve levels of rice production in central Myanmar, it is essential to assess the current practices used in the application of fertilizers. The aim of this study is to examine farmers’ knowledge and attitudes to the use of fertilizers for rice production and examine the constraints they face. A survey was conducted using structured questionnaires to interview 164 farmers, randomly selected from three villages in central Myanmar. The survey data were analyzed using descriptive statistics. Based on the survey results, commonly used fertilizers were urea and compound fertilizers. It was clear that the majority of farmers used amounts below that recommended amount in their application of urea and levels of application of mineral fertilizer varied greatly. About 23% of respondents used cow-dung manure and 12% applied pulses residues as fertilizers for rice cultivation. Although the farmers’ accept that fertilizer application is necessary for better rice growing, the majority of the farmers faced financial difficulties with any increased use of fertilizers. Also, this study shows that the sampled farmers’ limited knowledge on fertilizer use and the lack of access to the information related to fertilizer management, is a constraint preventing appropriate use of available fertilizers. Thus, clear improvements to increase agricultural productivity and soil fertility levels would result from the improved application of organic and inorganic fertilizers.

Adding value to agricultural products is expected to play an important role in increasing income and reducing poverty in rural areas of Cambodia. The promotion of agro- processing is one of the key strategies for the value addition. A variety of processed foods produced by individual small-scale farmers have helped generate income, with the exception of rice liquor which has been faced deficits and low profitability. This study aimed to clarify the socio-economic status of rice liquor farmers in rural areas and to examine the factors leading to deficits and surpluses in rice liquor production. Data on the economic status of rice liquor farmers and non-rice liquor farmers were collected by conducting structured interviews using questionnaires at the targeted areas in Takeo Province. Comparisons of the income structures of the two groups revealed that the rice liquor farmers mainly depended for income on agricultural activities including rice liquor production and pig rearing, whereas non-rice liquor farmers depended on non-agricultural activities such as off-farm businesses, labor work, and remittances. Rice liquor production was less profitable, and around 30% of rice liquor farmers faced deficits in this activity. A comparison of the economic status between deficit and surplus operations of rice liquor production revealed the key factors that caused deficits, such as a low sales price, high cost of rice, low productivity, and high frequency of production failure. Rice liquor farmers expected improvements in the production techniques, in the quality and productivity of liquor. Thus, modifying production techniques to improve the quality and productivity of rice liquor, and to reduce the rate of production failure are the key strategies to increase the profitability of rice liquor businesses.

Agriculture is the main industry in Cambodia and home-made agricultural products for local Khmer people are commonly sold at wet markets. However, food poisoning and food-related diseases frequently occur due to these home-made products. The improper handling of food by vendors, inadequate storing conditions, and cross-contamination risk while on display, were observed when inspecting wet markets. Sanitary conditions in the wet markets were poor and the food handlers seemed to treat food based on their personal experience. In this study, we aimed to investigate the hygiene level of food products sold in wet markets in Cambodia. In Kampong Cham, a typical small town, processed foods are consumed in the local area and are also transported to large cities, like Phnom Penh. Pickled vegetables, which are a popular ready-to-eat food in Cambodia, were selected and assessed for microbial contamination. A total of 17 pickles were collected from the local market in Kampong Cham and we measured the Brix value, salt concentration, and pH in these samples. Adenosine triphosphate (ATP) concentration was also measured, because the amount of ATP in a food sample indicates the approximate microbial contamination level. The five samples with the highest ATP values were used for a quantitative evaluation of microorganism contamination. In addition, five other samples with relatively low ATP concentrations were tested for comparison. An assessment of colony number and morphology indicated that nine of the samples showed initial putrefaction or putrefaction. There was one coliform-positive sample. Similarly, three pickles purchased in Phnom Penh showed putrefaction and two samples from these three pickles were coliform-positive. These results indicated that food sanitary conditions are unsafe and there is a critical need for improving food safety at wet markets in Cambodia.

Some pickles transported from the local province are sold in the wet markets of Phnom Penh, Cambodia. Therefore, products sold in Phnom Penh can be considered representative samples that reflect the approximate levels of bacterial contamination in the food supply chain of Cambodia. In this study, we conducted a microbiological inspection of the food samples from Phnom Penh to investigate the seriousness of the unsanitary conditions of food products. Eight kinds of pickles were purchased from three wholesale markets one week apart on two separate occasions. A total of 48 samples were used for microbial testing, and the values of Brix, pH, and salt content of these samples were measured. Although all food samples were purchased from the same markets and vendors, several pickles showed different results in the measured values between the first and second purchases. To determine the contamination level of the pickles, we targeted general viable bacteria, coliforms, fungi, Salmonella, Staphylococcus aureus, and Bacillus cereus. The total number of microorganisms detected by the aerobic plate count showed that 15 of 48 samples contained more than 7 log10 CFU/g of sample. Pickled onion and mustard showed relatively higher number of microorganisms compared to other products. Of the 48 pickles, 58.3% were coliform positive, 41.7% of the samples were Salmonella positive, and 83.3% and 37.5% were S. aureus and B. cereus positive samples, respectively. These results indicate that the products from the wholesale market of Phnom Penh are significantly contaminated with bacteria. In general, food contamination result from raw materials, cross-contamination, and poor water quality. Thus, it is important to educate food handlers regarding the practical knowledge to ensure proper food sanitation practices. The results of this study will be useful to reveal the cause of food contamination and to develop appropriate countermeasures.

An understanding of the physical and chemical properties of soils is necessary due their relationship with productivity in agricultural fields. A study was conducted in 480 hectares of agricultural fields at Kyee Inn, Pyinmana Township, Naypyitaw, Myanmar to determine the relationship between different soil properties (bulk density, soil moisture, soil pH, cation exchange capacity, organic matter, total nitrogen, total phosphorus, and total potassium) using Geographic Information Systems (GIS). Soil samples were collected on a grid method (300 m × 300 m) from three places in each grid at a depth of 0-15 cm. Global Positioning System (GPS) was used to determine the coordinates of sampling points. The collected samples were composited to 80 soil samples and analyzed. To compute the relationship between soil properties, simple linear correlation was performed using statistix 8^th version. Finally, the relationship among the soil properties was shown by overlay mapping in Arc Map 10.5 with the spatial analytical function of ArcGIS software. The results revealed soil pH was significantly and negatively correlated with total nitrogen (r = -0.412), and significantly and positively correlated with total phosphorus (r = 0.248). Total potassium content was highly significant and positively correlated with soil moisture (r = 0.782). The relationships that are commonly found among soil properties are evident in this study with a positive correlation of soil organic matter and total nitrogen (r = 0.058), a negative correlation of bulk density with soil organic matter(r = -0.191) and soil moisture (r = -0.066), a positive correlation of cation exchange capacity with total potassium (r = 0.204), and a negative correlation of cation exchange capacity with bulk density (r = 0.018), but these were not statistically significant. The observed information from this study can provide a clear understanding of the relationship among soil properties, which positively or negatively affect nutrient availability.

Unmanned Aerial Vehicle (UAV) has been recognized as a potential tool to obtain spatial information of crop state in small-scale farming fields. The objectives of this study are to assess the availability of UAV photographs to determine the plant height (PH) for three crop varieties (barley, oat, and perilla); and to evaluate the effect on the accuracy of the estimated PH caused by different plant shapes. The UAV photography and ground surveys were conducted weekly from May 31 to September 3, 2019, at the examination field of Obihiro University of Agriculture and Veterinary Medicine. The estimated PH was obtained from the differential value (D_value) of Digital Surface Models (DSMs) generated from UAV photographs through the Structure from Motion (SfM) process. The results demonstrate that the D_value of DSMs produced the highest estimation accuracy (R² = 0.97, RMSE = 9 cm) for perilla, which is a herb crop with luxuriant spade-shaped leaves, and a moderate estimation accuracy (R ²= 0.87, RMSE = 23 cm) for oat, which is a grain crop making small spikes during the heading time with lanceolate leaves. The estimated PH produced the lowest accuracy (R ²= 0.34, RMSE = 28 cm) for barley, which makes outward spikes with long prickly awns above the ear of grain. However, a higher accuracy (R² = 0.67, RMSE = 17 cm) for barley was obtained after a lodging of the spikes caused by rain on July 2. Furthermore, the accuracy of the estimated PH increased in both barley and perilla fields after corrected by plant coverage of the field. These findings suggest the D_value of DSMs obtained from UAV photographs can provide an accurate PH estimation for crops with luxuriant leaves like dicotyledons, but comparably less accurate estimation for crops with long and sharp leaves like monocots. Additionally, the elimination of the effect of unrecognizable factors such as long awns and non-plant factors such as the ground can also increase the accuracy of the estimated PH.

Organic or natural farming practices are known to promote soil fertility as well as biological diversity. Organic matter recycling, multiple cropping and ecological corridors are available as reservoirs for biological control agents such as predators or parasitic insects. These practices allow ecosystem services to reduce the presence of phytophagous insects and microorganisms. The objective of this study is to analyze the effect of the different farming systems on the diversity of arthropods. The sampling of arthropods was performed by pitfall trap method. The traps buried at surface level of the ground were set at 3.5 m intervals for 24 hours in the line of the cultivated crops. In addition to this method, Tullgren funnel method is applied in this study. In the experimental results, there were no significant differences in richness and abundance of observed arthropods. In the natural farming system, taxonomic group of Araneae, Acari and Coleoptera was observed. In the conventional farming system, the group of Formicidae was dominant. Using the Simpson’s (inverse) index and Shannon- Weaver’s index, the diversity was calculated. The results indicated there was more diversity of arthropods in the natural farming compared to conventional farming system. It is evident that agricultural practices (natural or conventional) may affect the diversity of arthropods within an agroecosystem.

African swine fever (ASF) is an acute infectious and deadly viral disease that affects domestic and wild pigs of all breeds and ages. ASF virus (ASFV) can spread vastly to non-infected pig population, but it cannot be transmitted from pigs to humans. In Cambodia, first ASF outbreak was transmitted from bordering countries and reported in five provinces. While estimated 70% of ASF widespread all over the country, local farmers experienced a greater economic loss. Among the four components of risk analysis, the study determines the risk assessment, and hazard identification plays a crucial step in risk assessment. The objectives of this study aimed to detect the presence of ASFV in pork on local markets through qualitative risk assessment approach and propose possible measurable recommendations to prevent ASF outbreak. The study was conducted during the period of ASF outbreak in August 2019, and the qualitative detection of ASFV was conducted on pork tissue samples selected from wet markets and supermarkets in Phnom Penh. Sample extractions were isolated from 30 pork tissue samples and detected virus by iiPCR. The qualitative result on detection of ASF virus is confirmed by PCR technique. The ASFV is found in pork tissue samples in wet markets and supermarkets. Of the 30 samples, 21 (70%) were found positive with ASFV, 6 in 9 (20%) tissue samples from supermarkets and 15 in 21 tissue samples from wet markets (50%) confirmed the presence of ASFV. With this result, it indicates that likelihood of the ASF virus transmission would be very likely to occur and the spread of ASF virus in pork tissue samples in wet markets and supermarkets is significantly prevalent, and the virus is likely to spread quickly. Scientifically, there is no vaccine to prevent ASF, and as recommended by FAO, the influenced policy-based implementation is required in place to minimize further production losses. The implementations must be strengthened through strict farm biosecurity guideline and slaughter of infected pigs, strict import regulation (border and movement control of live pigs) and heavy penalty to illegal import of live pigs. Based on this result, it may contribute to bring consumers’ and relevant stakeholders’ awareness to reduce high risk through early detection of ASFV at the slaughterhouses and markets by risk assessment approach. Further studies on risk management and risk communication to complete the risk analysis of ASFV in pork are highly recommended.

Ants are one of significant components of ecosystems. They play important roles in agro-ecosystem functioning and provide ecological services as bioindicator, pollinator and biological control. Ants are diverse taxonomic groups. The study of ant diversity in economic crop areas including guava, mango, custard apple and banana gardens in Nam Phong Watershed, Khon Kaen province was conducted during November 2017 to August 2018. Ants were collected using three random sampling methods: manual catching, plant litter sifting and syrup trapping. The result revealed that 5 subfamilies, 13 genera of ants were found in this study. Five subfamilies found in the studied sites comprised of Dolichoderinae, Formicinae, Myrmicinae, Ponerinae and Pseudomyrmecinae. The most common species of ant with wide distribution in the study area were Anoplolepis and Diacamma. The Shannon- Wiener’s species diversity index revealed that the diversity was highest in guava (0.36) followed by mango (0.35), custard apple (0.34) and lastly the banana garden (0.26). There was no dominant species of ant in the study areas. The β-diversity score, using Sorensen’s similarity coefficient to determine the similarity in community composition, was found highest between guava and custard apple garden at 62%, follow by between mango and guava garden at 46%, and between mango and the banana garden at 38%, the results indicated that ant species diversity was varied in the four studied sites. Therefore, the results from this study suggests that ant species diversity can be used to support agro- ecosystems management.

The temporal and spatial distribution of soil apparent electrical conductivity (ECa) was measured to elucidate the process of soil salinization in rainfed paddy rice fields in Khon Kaen, Thailand. Soil ECa was measured in 2.3 ha of paddy fields using a ground conductivity meter, utilizing the principle of electromagnetic induction. The average soil ECa was measured at 150 cm and 75 cm depth at 10 m intervals. Observations were conducted every two weeks for two months, from mid-May 2018 to mid-July 2018. The collected data were interpolated using an inverse distance weighted method with 1 m intervals and then analyzed in terms of temporal and spatial distributions. The results showed that (1) higher soil ECa was observed in the northern part of the study area near a swamp throughout the monitoring period; (2) the average soil ECa at a depth of 0–75 cm ranged from 233 to 282 mS/m, while it ranged from 236 to 268 mS/m at a depth of 0–150 cm; (3) the average soil ECa in the upper layer was slightly higher than that of the lower layer in May, but this difference became smaller over time and the situation reversed in mid-July; and (4) a larger spatial distribution was observed in the upper layer compared with the lower layer based on the difference of a coefficient of variation of soil ECa. A soil salinization process was clearly observed.

Nitrogen losses in the forms of ammonia and nitrous oxide emission are major causes for low nitrogen content in cow manure compost. In addition, nitrogen losses decrease the agronomic value of compost. In this study, rice husk biochar was added in cow manure to assess its effects on reducing nitrogen losses. Rice husk biochar is a product of thermochemical reaction in limited oxygen supply resulting in a product with micro-pores and large surface area with negative charge. A small scale composting experiment was designed and conducted using cow manure for a period of 60 days. Gases released were measured periodically with static gas chamber method. In addition, total nitrogen content and C/N ratio were analyzed. The experiment results showed that the loss of ammonia which is in peak during initial stages were lower in the treatments added with biochar. The cumulative ammonia emission was lowered by 12.6%, 14.5% and 23.2% in 5%, 10% and 15% biochar added treatments respectively, as compared to control. The cumulative gas flux result of N₂O showed similar trend to that of NH₃. N₂O emission was lowered by 40.0%, 46.4% and 60.4% in 5%, 10% and 15% biochar added treatments respectively, as compared to control. Furthermore, total nitrogen content and C/N ratio had better results in biochar added treatments. The obtained results may be attributed to the fact that micro-pores and negative charge in rice husk biochar adsorbed the nitrogenous compounds. Additionally, biochar increased retention of moisture and nutrients enhancing microbial activity for better degradation and humification of organic matter. The results indicated that biochar could be a good medium in reducing the nitrogen loss and increasing agronomic value during composting of cow manure.

Rice is an economically, socially, politically, and culturally important crop grown in diverse agro-ecological conditions all over Myanmar. Climate change impacts affect rice production directly and link in farming decisions for cropping systems. As the population keeps growing and climatic variabilities and extreme weather events keep increasing the marginal productivity of land would not be negligible for the food security and sustainable agriculture. This study was conducted to meet the objectives of to overview the socioeconomic characteristics of farmers, find out the serious problems faced by the farmers in rice production, know the most practicing coping strategy to adopt the weather variability and determine farmers’ preferred characteristics of rice and perception on climate change in rice variety selection. A sample of 203 rice farmers from Thazi Township were randomly selected and conducted interview. Descriptive analysis and weighted average method were employed. Rice varieties were very diverse and Manawthukha was the most favorite variety. The newly released salt tolerant variety, Pyi Myanmar Sein was adopted by only one percent of respondents. The farmers are quite aware of climate change and they claimed the extreme weather conditions are the most stressful to rice production and they want shorter duration variety in order to make sure the enough soil moisture because majority of them do not have access to irrigation water. Changing rice variety was the most cited coping strategy to climate change adaptation followed by changing crop, changing sowing time, practicing crop rotation, changing cultivation methods and managing fertilizer application. The most preferred trait was high yielding variety followed by high quality, resistance to disease, pests and drought.

Paddy fields in the Osaka Prefecture were heavily flooded by heavy rain in July 2018 due to levee breaches. To estimate the flooded area and water level, it was necessary to combine aerial- and ground-based surveying. Accordingly, aerial photographs of the flooded area were taken on the day after the heavy rain. In this study, we developed a digital surface model (DSM) of the flooded area using the structure-from-motion (SfM) software, which can produce three-dimensional (3D) models based on multiple aerial photographs and multiple ground control points (GCPs). Using the global navigation satellite system (GNSS), we surveyed the target area to observe the 3D coordinate values of the GCPs. The DSM of the flooded area could be made by the SfM with the aerial photographs and GCPs. The DSM was input into the geographic information system to analyze the flooded area and water level. The water levels were calculated from the differences between the DSM and the digital elevation model (DEM). We used airborne laser surveying to build the DEM because it provides higher accuracy than the SfM software. To check the accuracy of the DSM, we compared the elevations of the DSM on the ground points of non-flooded areas with those of the DEM, and the differences were found to be less than 0.2 m. Then, the water levels on the actual water level observation points were compared to verify their accuracy, and the differences were found to be less than 0.4 m. The flooded area was found by overlaying the water level on the existing map.

Agricultural management practices such as cover crop could restore soil physical and chemical properties, and in turn positive effect of crop productivity. However, it can vary with soil type, climate, and type of cover crop species. In addition, different cover crops provide different benefits to agricultural land. For instance, legumes (e.g. clover (Trifolium repers L.)) fix atmospheric nitrogen (N) for their own use. After terminating the legume cover crop, it will release N into the soil as the residues decompose and provide available N to the main crops. Some of cover crop (e.g. phacelia (Hydrophylloideae)) are able to suppress weeds or prevent insect damages by competition, shading, and allelopathy. Recently, researchers reported that cover crop mixture may provide greater diversity of benefits than monoculture cover crop. Therefore, the objective of this study was to demonstrate soil physical and chemical properties assessment under cover crops (clover, phacelia, and their mixture) vegetation.

Over the last several decades, Japan’s farming population has gradually decreased and the average age of farmers has risen. The recent agricultural census 2015 indicated that there were 2.09 million people engaged in agriculture, which is a reduction of 60% compared to three decades earlier. The decline in farming populations is robust and is taking place in many agricultural communities in Japan. However, the impacts of the declining farming population differ significantly on the basis of the conditions of farming land. Retirement of aged farmers provides farming opportunities for young, local farmers, consequently leading to an expansion in the size of farms. In fact, the average farm size per household in Japan doubled from 1.05 ha in 1985 to 2.20 ha in 2015. This represents a positive aspect of aging and the decreasing farming population. On the other hand, farmland abandonment has been prominent in the last 30 years, accounting for nearly 10% of total farmland. In the remote and mountainous areas of Japan, maintaining agricultural activities is increasingly difficult, thereby casting doubt on the sustainability of agricultural production and rural communities. In such a case, the average farm size does not increase, weakening rural economies and communities. This study uses approximately 14,000 community-level data in the Tohoku region of Japan and examines the land conditions that induce an increase in average farm size. The land conditions we consider are (1) steepness, (2) elevation, and (3) time-distance from a city. Quantile regression analysis is carried out to identify land conditions and other socio-economic variables associated with average farm size. Our regression analysis indicates that farm size does not necessarily increase where farm sizes are initially small, even in the case of declining farming population. Discussion within agricultural communities to build trust and consensus on distributional conflicts are considered to be an effective countermeasure to increase farm sizes in remote and mountains areas. The empirical evidence suggests the need for varied policy interventions in accordance with land conditions.

Japanese rural communities have experienced an aging population with a drastic decline in its size while more economic functions and workplaces have become concentrated in urban areas. Some rural communities in remote mountainous areas even face the further serious problem of extinction of their own community. Even with such a difficult situation, some rural communities have been successful in achieving the migration of their young generation back to their rural areas, and even in reviving their energy year by year. The objective of this paper, therefore, is to demonstrate how rural communities in remote mountainous areas in Japan can become empowered and resilient regardless of the serious threat of further depopulation and marginal settlement through a case study of a small-scale rural community in a remote mountainous area of Miyazaki Prefecture, Japan. The paper first overviews how rural communities have experienced depopulation over time together with changes in livelihood along with changes in lifestyle. Then, by describing how a small community in the study area was challenged to implement a series of projects by themselves, utilizing their local resources and cultures, it explains how a depopulated community could revive and gain confidence in themselves while receiving a lot of attention from visitors from outside. The study results show that the aged female population in the community is the key human resource as they can actually play an important role in the rural community, producing local valuable products and services. Moreover, the study points out the importance of maintaining and passing on rural communities’ identities to the next generations, while explaining why some of the young population now choose to live in such remote rural areas ‒ a shelter from the overly globalized and industrialized modern society.