Effects Of Green Manure And Straw Incorporation On Rice Yield, Nutrient Uptake And Soil Fertility

In the context of environmental protection and agricultural sustainable development, the research and application on green manure has been playing a greater attention, which is an essence in traditional cropping systems in China. Agriculture modernization doesn’t conflicted with the development of traditional agriculutual pattern. Combination the advantages of the traditional agriculature with modern sciences and technologies is more efficient way to promote current agricutrual productivity. The field experiments were carried out during 2013-2015 in 8 different counties, located in western mountainous area,, Jianghan plain and east hill in Hubei province to ascertain the effects of green manure cropping and straw incorporation(rice or rape) on rice yield and soil fertility. The main findings of these experiments are summarized below.1) Compared to single chemical fertilization, incorporation of 30t/hm2 Chinese milk vetch combined with 60% of chemical fertilizer furnished the statistically similar grain yield and nutrient uptake in rice. The treatment, GM+80%NPK recorded considerably higher grain yield compared with chemical fertilization alone.2) Significant variations in rice growth were observed under the influence of different green manure and straw incorporation treatments as well as soil fertility levels. A 2-3 year field experiments indicated that 6t/hm2 rice straw or 30t/hm2 green manure incorporation recorded statistically similar or higher grain yield under low and middle soil fertility levels compared with chemical fertilization alone. The combined application of green manure and rice straw incorporation was more beneficial for rice grain yield than alone. Rice straw incorporation increased the grain yield significantly in high fertility soil, while, incorporation of green manure was found to decrease the yield; the combined application of rice straw and green manure alleviated such decreasing trend. Combined green manure and straw application increased the soil organic matter, total nitrogen, available phosphorus and available potassium. Incorporation of straw added more potassium to soil than green manure. However, combined straw and green manure application was more effective in increasing the soil fertility in Hefeng and Xiao’nan field. However, single application of green manure or straw is more efficient than combined application of these two organic materials in Luotian.3) Single green manure and straw(rape residue and rice straw) incorporation can alleviate the acidification trend caused by chemical fertilizer application. Green manure or straw application with lime was more efficient in increasing the soil pH and improving grain yield than lime application alone. In short, the rape residue was more efficient in reclaiming soil acidity than rice straw and green manure.