黄淮海区不同土壤氮肥力水平下的玉米产量及其对氮肥施用的响应差异OA

[Objectives]This study aimed to investigate the yield differences caused by soil nitrogen(N)fertility levels and N fertilization across the main maize-producing areas of the Huang-Huai-Hai Plain.The findings will provide a theoretical foundation and technical support for enhancing maize production and optimizing N fertilizer management.[Methods]Using maize,N fertilizer,N application rate,and yield as keywords,we collected the experimental data on maize N fertilization conducted in the Huang-Huai-Hai Plain from 2000 to 2024 from both Chinese and English databases,including CNKI,VIP,Wanfang,Web of Science,and Google Scholar.The maize yield under no N application was defined as the soil native N-derived yield,and the soil N fertility levels were classified into four categories based on the soil native N-derived yield levels:<6 t/hm2,6-8 t/hm2,8-10 t/hm2 and>10 t/hm2.The yield difference among different soil N fertility levels,the N fertilizer-induced yield increase rate,contribution rate of N fertilizer to yield,and N fertilizer use efficiency were analyzed.The boundary line fitting method was employed to analyze the relationship between soil native N-derived yield and N-applied yield of maize,and the impact of soil N fertility levels on the gaps between predicted and actual yields.The effects of soil N fertility levels on the stability and sustainability of maize yields were also evaluated.[Results]Across the Huang-Huai-Hai Plain,the soil native N-derived yield,N-applied yield,and N fertilizer-induced yield increase rate averaged 8.07 t/hm2,10.06 t/hm2,and 28.19%,respectively.The proportion of maize yield obtained from the basic soil N supply that was below 8 t/hm2 was 52.12%.As soil N fertility levels increased from<6 t/hm2 to>10 t/hm2,the N-applied yield increased significantly from 8.37 t/hm2 to 12.78 t/hm2,while the yield increase rate decreased markedly from 58.03%to 14.41%.Over the 25-year period,soil native N and N fertilizer contributed an average of 81.46%and 19.80%to maize yield,respectively.The average partial factor productivity and agronomic efficiency of N fertilizer were 51.55 kg/kg and 9.93 kg/kg,respectively.The soil N fertility level did not significantly impact the partial factor productivity of N,while the N agronomic efficiency showed a significant decline with increasing soil N fertility levels.Using the boundary line method,the predicted maximum yield of maize in the Huang-Huai-Hai Plain was 15.25 t/hm2.As soil N fertility levels increased from<6 t/hm2 to>10 t/hm2,the gap between the predicted and actual yields decreased from 6.88 t/hm2 to 2.47 t/hm2,the yield stability index decreased from 0.22 to 0.11,and the yield sustainability index increased from 0.53 to 0.71.[Conclusions]In the Huang-Huai-Hai Plain,the proportion of areas with soil native N-derived yield below 8 t/hm2 is as high as 52.12%.The maize yield gap between the highest and lowest soil N fertility levels reaches 9.99 t/hm2,while the yield gap caused by N fertilizer application is 11.61 t/hm2.The higher the soil N fertility level,the higher the contribution rate of soil N to maize yield,and the better the yield stability and sustainability.Therefore,improving the basic soil N fertility level is a crucial measure to enhance nutrient use efficiency of maize and achieve a win-win situation in both economic and environmental benefits in the Huang-Huai-Hai Plain.