Effects Of Biochar And Tillage On Nutrient Absorption And Yield Of Maize Under Reduced Fertilizer

Maize production in Heilongjiang Province has the characteristics of large planting area and high fertilizer application,and there are potential environmental risks.The black soil of meadow has a heavy texture and a slow nutrient release rate,which limits maize production to a certain extent.According to the characteristics of meadow black soil,how to reduce the amount of chemical fertilizer application to maize by improving the efficiency of fertilizer use as taking into account the stable yield,to reduce the fertilizer and increase efficiency of maize is an important problem to be solved urgently in agricultural production.Biochar has a certain fertilizer conservation potential and improves soil physical structure,but whether it can achieve reduce fertilizer and efficiency of maize by adding biochar to the soil needs scientific data to answer.Therefore,a large-scale experiment was conducted to study maize in meadow black soil.On the basis of conventional straw returning,deep tillage(D)and rotary tillage(S)were set up.Farmers' conventional fertilization(F)was used as the control,and 20% reduced fertilizer treatment(F1)was set up.On the basis of 20% reduced fertilizer,two levels of biochar addition were set up: 2500 kg/hm2(B1)and 5000 kg/hm2(B2).Eight treatments were used to study the effects of biochar and tillage methods on nutrient absorption and yield of maize under reduced fertilizer,so as to provide scientific basis for ensuring stable yield of crops under the condition of weight loss.The main results are as follows:1.Compared with rotary tillage,deep tillage combined with biochar treatment increased the accumulation of nitrogen and phosphorus in maturity grains.Compared with SF1B1,DF1B1 increased the accumulation of nitrogen and phosphorus in maturity grains by 10.01% and 7.14%,and DF1B2 increased by 10.19% and 6.13% compared with SF1B2(p<0.05),but there was no significant difference in the accumulation of potassium in maturity grains(p>0.05).Under reduced fertilizer,the combined application of biochar promoted the accumulation of nutrients in maturity grains,and increased with the increase of biochar application.Under deep tillage,DF1B2 increased the accumulation of nitrogen and phosphorus by 10.73% and 5.85% in maturity grains compared with DF1B1,respectively.Under rotary tillage,SF1B2 increased by 9.68% and 6.86% compared with SF1B1,respectively(p<0.05),but there was no significant difference in the accumulation of potassium in mature grains(p>0.05).2.The effects of combination of biochar and tillage methods on dry matter accumulation in maize grains at maturity stage varied with tillage methods.Deep tillage of biochar was more beneficial to dry matter accumulation in maize grains.The dry matter accumulation of DF1B1 increased by 5.86% and that of DF1B2 increased by 5.26% in maturity compared with SF1B1(p<0.05).At the same time,the dry matter accumulation in maturity grains was increased by applying high biomass carbon and low biomass.Under deep tillage and rotary tillage,B2 increased by 5.55% and 6.15% compared with B1,respectively(p<0.05).3.Under the condition of reducing fertilizer,the yield of maize increased by 6.96% and 10.71% under the condition of deep tillage,3.21% and 8.51% under the condition of rotary tillage,respectively,compared with SF1B1 and SF1B2.Except for the difference between SF1B1 and SF1,the other treatments had significant difference(p<0.05).The application level of biochar had different effects on maize yield.High amount of biochar treatment was more conducive to the increase of maize yield.The yield of DF1B2 was 3.50% higher than that of DF1B1,and that of SF1B2 was 5.14% higher than that of SF1B1(p<0.05),In this experiment,DF1B2 was the highest yield treatment,reaching 1 1085.29 kg/hm2,while SF1B2 was the highest yield under rotary tillage,reaching 10 847.35 kg/hm2.4.Under the condition of reducing fertilizer,the agronomic efficiency,partial productivity and nitrogen use efficiency of nitrogen fertilizer in maize were improved by deep tillage combined with biochar than by rotary tillage combined with biochar,and the nitrogen use efficiency increased with the increase of biochar application under both tillage conditions,with B2 increasing by 7.03% and 12.08% respectively compared with B1 under deep tillage and rotary tillage(p<0.05).In conclusion,the effect of biochar on nutrient absorption and yield of maize varies with different tillage methods.Under the condition of 20% reduce fertilizer,deep tillage and rotary tillage combined with high biomass biochar(5000 kg/hm2)can improve maize yield and fertilizer utilization efficiency in meadow black soil.