@article{SHEN2023, 
author = {Zhe SHEN and TianFu HAN and XiaoLin QU and ChangBao MA and HuiYing WANG and KaiLou LIU and Jing HUANG and JiangXue DU and Lu ZHANG and LiSheng LIU and JiWen LI and HuiMin ZHANG},
title = {Spatial-Temporal Variation of Relative Yield Gap of Wheat and Maize and Its Response to Nitrogen Fertilizer in China},
year = {2023},
journal = {Scientia Agricultura Sinica},
volume = {56},
number = {14},
pages = {2724-2737},
keywords = {wheat, maize, relative yield, relative yield gap, nitrogen fertilizer},
url = {https://www.sciopen.com/article/10.3864/j.issn.0578-1752.2023.14.008},
doi = {10.3864/j.issn.0578-1752.2023.14.008},
abstract = {【Objective】This study aimed to explore the spatial-temporal variation characteristics and influencing factors of relative yield gap of wheat and maize in China during the past 15-20 years and the response of relative yield gap to nitrogen fertilizer under different soil productivity levels, so as to provide a theoretical basis for rational application of nitrogen fertilizer and the realization of high and stable yield of wheat and maize.【Method】Based on the long-term monitoring database, the difference of wheat and maize yield between fertilized area and non-fertilized area was used to represent the relative yield (RY). The highest relative yield (HRY), the average relative yield (ARY) and the relative yield gap (GRY) were obtained by using the statistical of high-yielding households, the effects of fertilization and soil factors on the relative yield gap were determined used the random forest model, and soil productivity level was divided according to the yield of non-fertilized area. The relationship between the relative yield gap of wheat and maize and nitrogen application rate under different soil productivity levels was quantified.【Result】HRY of wheat in China was 3.83-6.75 t·hm-2, ARY was 2.10-3.42 t·hm-2, and GRY was 1.73-3.33 t·hm-2, GRY accounting for 44.64%-49.06% of HRY. HRY, ARY and GRY of wheat were north China>middle-lower Yangtze Plain>northwest China>southwest China. HRY of maize in China was 6.53-8.20 t·hm-2, ARY was 3.37-4.12 t·hm-2, and GRY was 3.16-4.08 t·hm-2, GRY accounting for 44.78%-50.52% of HRY. HRY, ARY and GRY of maize were northeast China>north China>southwest China>northwest China. Except for north China, HRY and GRY of wheat and maize increased with time. Except in northwest China, the GRY decreased with the increase of nitrogen application rate in low and medium soil productivity, and the decrease amplitude was more significant in low soil productivity level, while the decrease of GRY with nitrogen application rate in high soil productivity was not significant. Regionally, the balance points of nitrogen fertilizer application were found in wheat and maize in North China, wheat in middle-lower Yangtze Plain, and maize in northeast China at low and medium soil productivity. Overall, the nitrogen application rate and soil organic matter were relatively important influencing factors of GRY for wheat and maize at low and medium soil productivity. Potassium application had a significant impact on the GRY in middle-lower Yangtze Plain and north China, while organic matter had a significant impact on the GRY in the northwest and southwest China under high soil productivity.【Conclusion】N application and soil organic matter were important factors affecting the relative yield gap. The higher soil productivity level, the lower the effect of nitrogen fertilizer on reducing the relative yield gap. N fertilizer should be reduced appropriately in high productivity soil. In order to increase yield and avoid the waste of resource and environmental risks, it was suggested that the application rate of nitrogen fertilizer should not exceed its balance point. The recommended application rates of nitrogen fertilizer were 260.6 and 159.2 kg·hm-2 for wheat and 262.5 and 246.0 kg·hm-2 for maize at low and medium productivity levels in north China, respectively. In the middle-lower Yangtze Plain, 199.5 and 187.5 kg·hm-2 were recommended for nitrogen application at low and medium productivity levels, respectively. In northeast China, the recommended amount of N fertilizer application was 259.5 and 228.0 kg·hm-2, respectively. Under low and medium productivity levels in southwest and northwest China, N fertilizer should be appropriately increased. The potassium fertilizer reasonable application should be paid more attention at high soil productivity in north China and middle-lower Yangtze Plain. The improvement of soil organic matter should be as the main measures to achieve high and stable yields in southeast and southwest China.}
}