The Study On The Capacity Of Sheep Dung Fertilized In Rice And Wheat Farmland Environmentally Compatible With High Yield

Multiple cropping of rice and wheat continuous cropping is the main planting method in double cropping area.The important way is developing cycle agriculture that agriculture combined animal husbandry(herbivores)to achieve the synergy among high efficiency of rice and wheat,fixed carbon and emission reduction and non-point source pollution controlled and reduced.One of the key nodes that "Grass(straw)-sheep-field" Modern circulation of agricultural of material circulation flow is returning sheep dung to field reasonably.The core is the proportion of sheep manure substituting fertilizer and farmland dung maximum bearing capacity in farmland environmentally compatible with high yield.The experiment is the field contrast design,that taking simple composting fermentation sheep droppings as experimental material.The experiment studies the differences in characteristics,under the condition of different proportions of sheep dung instead of chemical fertilizer and the dosage of pure sheep dung,that rice and wheat yield,nutrient used,the risk of non-point source pollution,soil fertility characteristics.The experiment monitors the dynamic,under the condition of the same nitrogen replacement,that farmland greenhouse gas emissions from Pure chemical fertilizer treatment and Pure organic fertilizer treatment.Putting forward the appropriate proportion of sheep manure substituting fertilizer and farmland dung appropriate bearing capacity in farmland environmentally compatible with high yield.The main conclusions are as follows:(1)Under the condition of the same nitrogen replacement,with the increase of dung organic nitrogen replacement rate,the rice yield,the wheat yield and the annual yield of rice and wheat rotation present the trend of increased at first and then decreased.The rice yield that dung suitable organic nitrogen replacement rate is 33.71%～67.39%,is more than the rice yield that single chemical fertilizer treatment.when dung organic nitrogen replacement rate is 50.55%,the rice yield reached the highest yield,that is 10306.7kg/hm2.The wheat yield that dung suitableorganic nitrogen replacement rate is 26.36%-74.41%,is more than the wheat yield that single chemical fertilizer treatment.when dung organic nitrogen replacement rate is 50.55%,the wheat yield reached the highest yield,that is 5431.0kg/hm2.The annual yield of rice and wheat rotation that dung suitable organic nitrogen replacement rate is 29.17%～71.74%,is more than the annual yield of rice and wheat rotation that single chemical fertilizer treatment.when dung organic nitrogen replacement rate is 50.39%,the annual yield of rice and wheat rotation reached the highest yield,that is 15737.7kg/hm2.(2)Under the condition of the same nitrogen replacement,with the increase of dung organic nitrogen replacement rate,the rice and wheat plant nitrogen nutrient content and nitrogen accumulation present the trend of increased at first and then decreased.But nitrogen dry matter production efficiency and nitrogen grain,production efficiency present the trend of decreased at first and then increased.But,the contents of total nitrogen,total phosphorus,Available potassium and soil organic matter all increase,and total nitrogen and total phosphorus increase significantly.Synthesizing high-yielding rice and low risk effect of nitrogen and phosphorus concentration in surface water,when dung organic nitrogen replacement rate is 50.55%,the rice reached the highest rice yield.Under the condition of the dung organic nitrogen replacement rate of 50.55%,surface water of TN and TP average concentration is in the range of safety threshold.(3)In the rice season,CH4,N2O and CO2 emissions of pure organic fertilizer treatment is more than CH4,N2O and CO2 emissions of pure chemical fertilizer treatment,but there is no significant difference between treatments.Compared with the pure chemical fertilizer treatment,CH4 emissions of pure organic fertilizer treatment is decreasing,and N2O and CO2 emissions of pure organic fertilizer treatment is increasing,but there is no significant difference between treatments.Compared with the pure chemical fertilizer treatment,global warming potential and greenhouse gas intensity of pure organic fertilizer treatment is increasing,but there is no significant difference between treatments.Global warming potential and greenhouse gas intensity in the rice season is much higher than that global warming potential and greenhouse gas intensity in the wheat season.(4)With the increase of dung organic fertilizer,the rice yield,the wheat yield and the annual yield of rice and wheat rotation present the trend of increased at first and then decreased.Whendung the content of sheep dung organic fertilizer is 1.56 times of single chemical fertilizer treatment,the rice yield,the wheat yield and the annual yield of rice and wheat rotation reached the highest yield.The trend of the rice and wheat plant nitrogen nutrient content and nitrogen accumulation is in accordance with rice yield trend.But the trend of nitrogen dry matter production efficiency and nitrogen grain production efficiency show the opposite trend.Synthesizing high-yielding rice and low risk effect of nitrogen and phosphorus concentration in surface water,when dung the content of sheep dung organic fertilizer is 1.56 times of single chemical fertilizer treatment,the rice yield reached the highest yield.Under the condition of the content of sheep dung organic fertilizer that is 1.56 times of single chemical fertilizer treatment,surface water of TN and TP average concentration is in the range of safety threshold.