| In order to deeply analyze the impact of chemical fertilizer reduction on the control of agricultural non-point source pollution in the river basin,promote the resource utilization of straw,livestock and poultry,and implement the requirements of green agricultural development.Further systematic research is needed on the effects of nitrogen substitution fertilizers such as organic nutrients on crop yield,fertilizer use efficiency,soil fertility and nitrogen and phosphorus loss in farmland during agricultural planting.In this study,eight treatments,CK(no fertilizer application),CF(routine fertilization),100%,50%and 30%of organic fertilizers such as pig manure and straw,were established in a typical rice-wheat crop rotation system in the Chaohu Lake area.After five consecutive years of long-term experiments,we studied and analyzed the characteristics of rice and wheat yield,fertilizer use efficiency,soil fertility,and nitrogen and phosphorus loss from farmland.It provides scientific support for chemical fertilizer reduction,agricultural green development and agricultural surface source pollution management in Chaohu Lake basin.The main research results are as follows:(1)Organic nutrient substitution treatment with the same nitrogen content,wheat and rice yields were 1372.22-4611.11 kg/hm~2 and 3943.33-10364.44kg/hm~2 respectively,which were -63.84%-21.52%and-54.59%-19.36%higher than the high yield treatment.And the yield under 50%substitution treatment was the highest.Wheat and rice yields under the treatment of organic fertilizer substituted by straw were higher than that by pig manure and were the highest under 50%replacement of organic fertilizer by straw.(2)30%and 50%replacement of organic fertilizer improved the uptake of N and P nutrients by crops.Under 50%replacement of organic fertilizer by straw,the partial factor productivity of N and P fertilizer of wheat and rice,agronomy utilization rate and uptake rate were increased compared with CF treatment.And 100%replacement significantly reduced the nutrient absorption efficiency of crops.(3)Organic nutrient substitution treatment with the same nitrogen content,the N and P loss in wheat field was 18.69-27.74kg/hm~2 and 0.30-0.47kg/hm~2,respectively,which were reduced by 18.10%-44.82%and 6.00%-40.00%compared with CF treatment.The 50%replacement of organic fertilizer treatment significantly reduced the N and P loss in wheat field water,and there was no significant difference between the replacement of pig manure and straw organic fertilizer.(4)Seven days after organic fertilizer application,the average concentrations of N and P in rice field water were between 7.50-10.55mg/L and 0.40-0.54mg/L,which were 10.90%-36.66%and 6.90%-31.03%lower than CF treatment respectively,significantly reduced by the organic fertilizer substitution treatment.(5)Under iso-nitrogen replacement treatment,the runoff loss of nitrogen and phosphorus in paddy fields was 1.30-3.68kg/hm2 and 0.05-0.17kg/hm2,respectively.Under the straw organic fertilizer replacement treatment,the runoff loss of paddy field was lower than that of pig manure organic fertilizer,and the TN and TP loss were reduced by 40.99%and 37.89%,respectively.(6)Organic nutrient substitution treatment with the same nitrogen content can effectively increase soil p H and soil nutrient content,and is positively correlated with the proportion of it.Under organic substitution,the content of soil organophosphorus was increased by 36.87%compared with CF treatment.And the proportion of active and moderately active organophosphorus under organic substitution by pig manure was significantly higher than that by straw.(7)50%organic nutrient replacement treatment can effectively improve soil physical and chemical properties,increase crop yield,and reduce the risk of nitrogen and phosphorus loss in farmland. |
PDF Full Text Request