Effects of Nitrogen Application on Dry Matter Accumulation and Nitrogen Absorption of Silage Corn
A field experiment was conducted to compare traditional nitrogen application with optimized nitrogen application in terms of dry matter accumulation,soil plant analysis development(SPAD)value,soil nitrate nitrogen and aboveground nitrogen uptake in silage corn.The results showed:(1)Compared to the traditional method of applying all fertilizers as base(235 kg N/hm2),the optimized nitrogen application significantly reduced the accumulation of dry matter in the aboveground part,SPAD value,and soil nitrate nitrogen content in the 0-30 cm soil layer before the 6th leaf stage of silage corn growth.Additionally,the nitrogen concentration in the aboveground part was significantly lower under the optimized nitrogen applica-tion than under the traditional fertilization approach.The soil nitrate nitrogen content in the traditional fertil-ization treatment decreased rapidly over time,failing to meet the nitrogen demand in the aboveground part during later growth stage.Consequently,nitrogen uptake and the accumulation of dry matter in the aboveg-round parts were significantly lower in the traditional fertilization treatment compared to the optimized treat-ment.(2)Adjusting the fertilization structure and applying part of the nitrogen as topdressing could main-tain a stable yield while reducing nitrogen input by 25%to 50%.Moreover,the residual nitrate nitrogen in the 0-90 cm soil layer decreased by 35.36%to 51.48%.(3)The optimal yield was achieved with a nitro-gen application of 156-180 kg/hm2(basic fertilizer+topdressing),which increased the yield by 3.37 t/hm2 compared to the traditional fertilization treatment.(4)It was also observed that the production of 1000 kg silage corn resulted in an uptake of 7.78 to 10.15 kg of nitrogen in the aboveground parts.In conclusion,the optimized nitrogen application method can maintain the yield of silage corn while minimizing nitrogen loss and reducing environmental risks.These findings are significant for guiding the practical production of silage corn.
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