State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Tai'an 271018, Shandong, China.
Beijing Maize Seed Testing Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China.
Sci Total Environ. 2021 Apr 1;763:143035. doi: 10.1016/j.scitotenv.2020.143035. Epub 2020 Oct 20.
To meet the food demands of a growing population, the maize production systems deployed by smallholders in China have tended towards extremely intensive planting and excessive use of fertilizers, which have caused serious environmental impacts. This study investigated the balance between the maize yield and nitrogen (N) input in the North China Plain (NCP), which is one of the most important grain-producing region in China. Our study compared yield simulations generated by the DSSAT-CERES-Maize model with actual data from a number of multi-site field experiments and an extensive household surveys encompassing 1671 farmers. The smallholders' maize cultivars, plant population, and amount of N input on the crop yield and how these affects the economic benefits were analyzed. The results showed that the average traditional farming methods' yield was 72% of the attainable yield, which means that farmers have ample room to improve their yields. We also found that the maize yields varied widely between farmers, and that most of them applied excessive amounts of N but failing to achieve an optimal yield due to poor fertilization management techniques. The study found that the economic benefits achieved by the farmers were low, but after deploying high-yield (HY) methods, the yield was increased by 34.9% and the economic benefits by 14.4%. The greenhouse gas (GHG) emissions associated with the traditional farming methods were high and could potentially be reduced by 48.6%. All in all, farmers should be given guidance on how to appropriately increase the plant population, reduce the input of N fertilizer, and optimize farmland management measures, so that China can achieve intensive but sustainable agricultural production at a lower environmental cost. It was concluded that there are still numerous biological and abiotic factors that restrict production increases by smallholders. These factors vary from region to region and require further investigation.
为了满足不断增长的人口的粮食需求，中国小农经营的玉米生产系统趋向于极度密集种植和过度使用化肥，这造成了严重的环境影响。本研究调查了中国最重要的粮食产区之一——华北平原的玉米产量与氮（N）投入之间的平衡。我们的研究将 DSSAT-CERES-Maize 模型生成的产量模拟与来自多个多点田间试验和广泛涵盖 1671 个农户的家庭调查的实际数据进行了比较。分析了小农的玉米品种、种植密度和作物产量的 N 投入量以及这些因素如何影响经济效益。结果表明，传统耕作方法的平均产量仅为理论产量的 72%，这意味着农民有很大的增产空间。我们还发现，玉米产量在农户之间差异很大，大多数农户施用了过量的 N，但由于施肥管理技术不佳，未能达到最佳产量。研究发现，农民的经济效益较低，但采用高产品种（HY）方法后，产量增加了 34.9%，经济效益增加了 14.4%。与传统耕作方法相关的温室气体（GHG）排放量较高，通过采用 HY 方法可减少 48.6%。总的来说，应该指导农民如何适当增加种植密度、减少氮肥投入和优化农田管理措施，以便中国能够以较低的环境成本实现集约化但可持续的农业生产。结论是，仍然有许多生物和非生物因素限制了小农的产量增加。这些因素因地区而异，需要进一步调查。
