We simulated alternate wetting and drying (AWD) conditions in incubation and pot experiments by creating anaerobic and aerobic soil conditions and then compared them with continuously flooded conditions to investigate the effects of different N sources on N transformation in paddy soils and Indica rice growth. Six different N sources were used (control, cow dung (CD), chicken manure (CM), ammonium sulfate (AS), AS+CD, and AS+CM) at a rate of 120 kg N ha^-1 with two water regimes [continuous flooding (CF) and simulated AWD]. In the incubation studies, AWD caused a high loss of N due to increased ammonification and nitrification during the aerobic periods, followed by subsequent denitrification during anaerobic periods compared with those in CF. Despite this, the grain yield in CF and AWD were not significantly different (14.3 and 14.4g pot^-1, respectively). N concentrations in grain and straw were statistically higher in AWD, 15.09 and 2.99 g N kg^-1 than in CF, 3.79 and 2.69 g N kg^-1, respectively. These results indicate that AWD may trigger soil N mineralization and lead to sufficient N uptake by rice plants, despite simultaneously causing significant N loss. Types of N fertilizers were the main factors controlling rice yield and N uptake, and we found no significant interaction between water regimes and N sources.

On Sangihe Island, North Sulawesi, Indonesia, the present conditions of cultivation and utilization of ‘sagu baruk’ were investigated, and its growth characteristics and starch productivity were also evaluated. There, ‘sagu baruk’ has been cultivated and used for a long time, and the starch extracted from the pith of the trunk has been used for self-consumption and selling. Its optimal harvest stage was from the first inflorescence (female inflorescence) emergence stage to the fruit color change of the second inflorescence (female inflorescence), and the number of years until the optimal harvest was around 15 years. The trunk length at the harvest was as long as about 20 m, but the diameter was as thin as 15 cm, and the trunk weight was 450–500 kg. The starch percentage in the pith was 50–55％, and the starch content per plant was about 90 kg. Although the starch content of ‘sagu baruk’ was significantly inferior to that of sago palm, and even inferior to that of sugar palm, it was presumed to have a high potential as a starch resource crop because of the easier harvesting, transportation of the trunks, and starch extraction due to the thinner nature of trunk and superior whiteness of the starch.

Cannabis (Cannabis sativa L.), known as ‘ganja’ in Bangladesh, is an important multi-use crop that has many potential applications. Ganja cultivation in Bangladesh has a long history. It was cultivated from the late 18^th century until 1987, when it ceased because of Bangladesh’s commitment to an international narcotics agreement. There is a wealth of historical information about the cultivation, regulations, and sale of ganja in the Naogaon District of Bangladesh. However, these records are in very poor condition. Many are handwritten in the local language, are poorly archived, and are stored under unsuitable conditions. The aim of this study was to collect and summarize them before they disintegrated. Here, we provide important information collected from these historical records. We describe the introduction of ganja to Bangladesh by the British and summarize historical information about the cultivation area and the volumes, prices, and grades of ganja. We also discuss policies that were developed to regulate the industry and protect farmers’ livelihoods. Although data are not available for the whole history of the cultivation, our dataset is the most complete record of information related to ganja in Bangladesh. This traditional knowledge and historical information will be useful to explain new agricultural strategies in the future.

As the Green Revolution initiated in the late 1960s was expected to affect paddy soil fertility considerably, information on the long-term changes of the total content of elements and micronutrient status of paddy soils in Thailand were investigated. Totally, 65 soil samples were collected in 2015 and 2016 from the surface layer of paddy fields in the northeast, north, central plain, and Bangkok Plain of Thailand. Total content of 13 elements (Si, Fe, K, Ca, Mg, Na, Mn, P, Cl, S, Ni, Cu, Zn) and available Mn, Fe, Cu, Zn, S and B contents were determined, and compared with those in the 1960s collected at or near the same locations. Total contents of the 13 elements in the 2010s were relatively lower than those of the world soil except for Si, and the total contents in the northeastern region were considerably lower than other regions except for Si. Total K, Mn and Si contents in 2010s were significantly lower than those in the 1960s (p < 0.01), suggesting the possibility of accelerated weathering by agricultural intensification. The available Mn and Fe contents were sufficiently present in all the fields, whereas available Cu, Zn, S and B contents of dominant soils in the northeastern region were below the threshold for deficiency. It is, therefore, recommended to apply more K fertilizer to maintain the level of soil K, and to apply more organic fertilizers with a variety of micronutrients, especially in the northeastern region.

When rice bran is stored for a long time, the free fatty acid (FFA) concentration in rice bran oil increases; hence, it is difficult to use the oil as a fuel for diesel engines. This study aimed to promote electrification using biofuel derived from rice bran oil; in order to use rice bran oil as a fuel, it is necessary to control the increase in the FFA concentrations. A low-cost and simple treatment of preserving rice bran that also considers the safety of defatted rice bran intended for consumption was investigated and the heat treatment method was selected. Milled rice bran was treated at 100℃ for 1 h and stored at 30℃ for 6 months; the FFA concentration in the rice bran oil was suppressed to approximately 10%. At this concentration, FFAs do not notably corrode engine components and affect oil viscosity; therefore, rice bran oil can be used as a fuel. Although there is no noticeable difference between the properties of Japanese rice and the New Rice for Africa (NERICA), we confirmed that the same effect could be achieved in NERICA. Overall, heat treatment effectively inhibited rice bran deterioration during storage, by suppressing the increase in FFA concentration in the oil and reducing oxidative damage.