Mulching type-induced soil moisture and temperature regimes and water use efficiency of soybean under rain-fed condition in central Japan

Soybean(Glycine max)is a high water-demand crop and grown under moderate temperature in Japan.To protect the crop from hot summer and to utilize rainfall for its cultivation,selection of appropriate mulching material(s)is crucial.For optimum production of the crop,soil moisture and temperature regimes as well as water use efficiency(WUE)of the crop were investigated under straw,grass,paper,plastic and bare soil(control)mulching under rain-fed condition at Gifu university farm in Japan.The mulching treatments,compared to the control,lowered soil temperature by 2°C at 5 cm depth and 0.5°C at 15 and 25 cm depths.The plastic and straw mulching stored the highest quantity of soil moisture at 5 and 15 cm depths;the bare soil stored the lowest quantity.At 25 cm depth,soil-moisture content was the highest under paper mulch but invariable under the other mulches.Plastic mulching reduced evaporation rate from the soil surface and,consequently,the reduced soil-water consumption(SWC)from the root zone augmented WUE of soybean.The paper mulching,by conserving soil-moisture and reducing soil temperature,provided better crop growth attributes,while the plastic mulching improved WUE of green soybean.Therefore,the plastic mulch performed best in reducing soil-water consumption and increasing WUE,while the paper mulch was good for soil-moisture conservation and temperature modification that increased soybean yield.

Climate change impact assessment on three major crops in the north-central region of Bangladesh using DSSAT

The potential consequences of climate change emanated from global warming are very alarming;the greatest concern is the potentially disastrous consequences on crop agriculture and food security in many parts of the world.Bangladesh is a country highly susceptible to climate change,but information in this regard is still inadequate.This study investigated the effects of climate change on three major crops-wheat,potato and rice-in the north-central region of Bangladesh.Two climate change scenarios,A2 and B2,of the Intergovernmental Panel on Climate Change(IPCC)were generated by employing MAGICC/SCENGEN model together with the observed climate data of the region.The growth and yield of the crops were simulated using DSSAT CERES-Wheat,SUBSTOR-Potato and CERES-Rice models under the present and projected future changing climatic conditions.For a predicted 5.32℃ increase in temperature in the year 2100,the yield of wheat,rice and potato would decrease by 47.6%,67.8%and 38.6%,respectively.The increased temperature would accelerate physiological maturity of the crops as reflected by their reduced length of growing season(LGS)by 1.20%to 18.5%.The reduced LGS would reduce seasonal evapotranspiration(ET)of the crops by shortening time-span for ET generation.Due to dominant yield reduction over ET reduction,the water use efficiency(WUE)for grain/tuber and biomass yields would decrease with the changing climate.The reduced crop yields are an indicative of a potential future risk of food security in Bangladesh.The results of this study can therefore guide to adopt coping mechanisms in the light of climate change to ensure future food security of the country.