Comparing The Effects Of Biofertigation Models On Yield Increase And Salt Restraint Of Film Mulched-Drip Irrigated Cotton Field

Cotton is one of the important economic crops in Xinjiang’s agricultural development.With the large-scale application of drip irrigation during recent years,the cotton industry has grown significantly.However,secondary salinization as well as excessive and unbalanced fertilizer application have affected the sustainable development of cotton production.In this study,plot experiments and field experiments were designed to study the impact of different management measures on cotton.The field experiment was carried out in Sangonghe Town and Xinhu Farmland in 2018.Controls and treatments(application of soil amendment)were set up.Each treatment was repeated 3 times.The suitability of applying soil amendment on different salinized soils were determined by measuring the pH and electrical conductivity in the soil.The plot experiment was carried out at the cotton breeding base of Xinjiang Agricultural University in 2019.There are seven treatments,i.e.,control(CK),fertigation(IF),biofertigation(IFO),water saving 10%+biofertigation(0.9IFO),reducing fertilizer 20%+fertigation(I0.8F),reducing fertilizer 20%+biofertigation(I0.8FO),water saving 10%+reducing fertilizer 20%+biofertigation(0.9I0.8FO).Each treatment was repeated three times,and the plots were randomly arranged.By studying the effects of different biofertigation models on the growth,yield,yield components,and water and fertilizer utilization of cotton,we tried to seek the best fertilization treatment to increase cotton yield,to select the best fertilization plan that takes into account of economic and environmental benefits,and to provide theoretical basis for biofertigation application model.After two years of experiment,the conclusions are as follows:1.Under the conditions of this experiment,compared with other management models,the plant height,SPAD value and dry matter accumulation of cotton under the biofertigation(IFO)model were significantly increased,which increased by 27%,1-4%and 60%-102%,respectively,when comparing with control.Reduction of 20%fertilizer application did not significantly affect the plant height,SPAD value and dry matter accumulation of cotton.In terms of basal diameter,there were differences among these models,but not significant.2.Based on the analysis of yield components,it was found that lint percentage was not affected by human factors.Due to application of soil amendment and bio-organic fertilizer,the number of bolls per plant and boll weight would be increased by 35%-40%and 15%compared with control.Among all models,the highest yield is the biofertigation(IFO)model,which has a yield of 5.5×103 kg/hm2,and the highest economic benefit of 3.5×103 yuan/hm2 is also obtained.3.Fertilizer supply is positively correlated with water use efficiency and agronomic use efficiency,and negatively correlated with partial productivity.The biofertigation(IFO)model with soil amendment and bio-organic fertilizer can effectively improve fertilizer agronomic utilization efficiency to 4.3 kg/kg.Reducing fertilizer 20%+biofertigation(I0.8FO)model can effectively improve partial productivity to 10.8 kg/kg,which is the highest of all models.At the same time,the water use efficiency was also improved to a certain extent,water use efficiency of IFO model reached 1.7 m3/kg,which was the best among all models.4.Application of soil amendment and bio-organic fertilizers could significantly increase contents of soil available nutrients,and could increase soil organic matter by 16%-26%.Moreover,reduce the amount of fertilizer supply could reduce available nitrogen content by 5%,and reduce available phosphorus content by 7%,while had no significant effect on contents of soil available potassium and organic matter.Reducing irrigation water amount by 10%could reduce contents of available nitrogen and available phosphorus in soil,while its effect was not significant,and it also had no effects on contents of available potassium and organic matter in soil.5.The effect of soil amendment depends on the degree of soil salinization.When soil electrical conductivity is higher than 2000 μs/dm,application of soil amendment can effectively reduced its electrical conductivity.However,it had no significant effect on soil with electrical conductivity of 1000 μs/cm.In terms of soil pH,the higher soil pH value was,the lower the effect of modifiers on regulating soil pH.The mixed application of soil amendment and bio-organic fertilizer could reduce soil pH by 2%-3%.Salt inhibition effect was obvious at 0-20 cm soil layer.Water saving by 10%and reducing fertilizer by 20%had no effect on soil pH and electrical conductivity.6.To sum up,under the experimental conditions,the best model is biofertigation(IFO)model,which is the best fertilization scheme considering both economic and environmental benefits.