Characteristics of straw phosphorus and potassium release and their effects on maize yield under different straw returning patterns
In this study,a field experiment was conducted in Siping City,Jilin Province for two consecutive years(2021-2022).The nylon mesh bag method was used to determine the release rate of straw phosphorus and potassium under two straw returning methods of straw mulch(SM)and straw bury(SB)and two nitrogen application levels of no nitrogen fertilizer(N0)and N 180 kg·hm-2(N180).The purpose of this study was to clarify the response of maize straw phosphorus and potassium release to returning methods and nitrogen fertilizer management in black soil area and its effect on maize yield.The results showed that returning methods and nitrogen application significantly affected the release of phosphorus and potassium from straw.The average two-year cumulative release rate of phosphorus in SB treatment was 69.7%,which was significantly higher than 54.5%in SM treatment.Compared with N0 treatment,the phosphorus release rate of straw increased by 12.3%.The average two-year cumulative release rate of straw potassium in SB treatment was 95.6%,which was significantly higher than 94.2%in SM treatment.The effect of nitrogen application on the cumulative release of straw potassium was also significant,and the fertilizer nitrogen input increased the cumulative release rate of straw potassium by 1.1%.By estimating the substitution potential of straw phosphorus and potassium,it was considered that the substitution potential of straw phosphorus to phosphorus fertilizer(P2O5)was low,which was 9.1 kg·hm-2.However,the substitution potential of straw potassium for potassium fertilizer(K2O)was higher,which was 141.0 kg·hm-2.The two-year returning method had no significant effect on maize yield,but there was a certain difference in the number of grains per ear.The number of grains per ear of maize was 430 grains·ear-1,which was significantly higher than that of 409 grains·ear-1.Nitrogen application significantly promoted the formation of yield and increased the yield of maize.Compared with N0 treatment,the yield of maize increased by 7707 kg·hm-2 in two years.By combining the comprehensive analysis of straw phosphorus and potassium nutrient release,it is considered that the phosphorus and potassium nutrients released by straw are beneficial to the formation of panicles and grains under the condition of sufficient nitrogen supply in black soil area,so as to ensure stable yield.
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