Legume Genomics and Genetics 2025, Vol.16, No.6, 253-269 http://cropscipublisher.com/index.php/lgg 261 The interactive management of dense planting and fertilization needs to respect the biological characteristics and adaptation strategies of crops. On the one hand, it is necessary to prevent management measures from exceeding the range that crop plasticity can adjust (such as irreversible yield loss caused by excessive density); on the other hand, management can stimulate crop potential (such as stimulating marginal branching and pod formation, extending the functional period, etc.). For different ecological regions and varieties, we should deepen the research on the physiological mechanisms of crop dense planting tolerance and nutrient efficiency to provide a basis for adjusting cultivation measures. For example, through field phenotypic observation combined with molecular marker analysis, we can screen out genotypes related to dense planting tolerance and fertilizer tolerance to guide breeding and cultivation. This will help to further improve the adaptability of legume crops to resources and the environment, and achieve the maximum yield benefit of dense planting and fertilization optimization. 5 Case Study: Regional Dense Planting and Fertilization to Increase Yield This study selected two typical bean planting areas in the north and south of my country, Zhumadian, Henan and Qiqihar, Heilongjiang, to analyze the application effects of dense planting and fertilization technology in different regions and different rows of crops. These two regions represent the main peanut producing areas and soybean producing areas, respectively, with very different ecological conditions and typicality. 5.1 Demonstration of high-yield dense planting and fertilization of peanuts in Zhumadian, Henan Zhumadian is located in the southern part of the Huanghuai Plain and is an important peanut production base in China, with annual planting area and total output ranking among the top. However, the long-term continuous planting of peanuts in the local area has led to a decline in soil fertility and aggravated pests and diseases, limiting the increase in yield. In order to solve this dilemma, in recent years, local agricultural departments and scientific research institutions have cooperated to carry out high-yield demonstrations of dense planting and matching fertilization for peanuts. The demonstration field adopts a planting density that is about 20% higher than the traditional density (about 180,000 plants/hectare), and applies soil testing and formula fertilization technology: on the basis of applying sufficient organic fertilizer as base fertilizer, nitrogen, phosphorus and potassium are applied in a balanced manner (the ratio of the three elements is about 1:0.8:1.2), and trace element fertilizers such as calcium, boron and molybdenum are added to prevent deficiency. In terms of fertilization methods, mechanical deep fertilization and layered strip fertilization are promoted, that is, slow/controlled release fertilizers are applied to the root concentration layer. A series of technical integrations have significantly improved the growth environment of peanuts. The demonstration results show that the individual robustness of peanuts in the densely planted and fertilized fields is not significantly lower than that of conventional ones, while the number of pods in the group has increased significantly, and the average yield per mu has increased by about 15% to 20% (Figure 1) (Wang et al., 2022). Among them, the treatment with special slow-release fertilizers and layered application has the best yield increase effect, with an average increase of 19.0% to 27.3% over the conventional yield of farmers in two years. At the same time, the roots of the plants penetrate deeper during the pod-setting period, and the dry weight and length of the roots in the 0 cm-20 cm soil layer are significantly higher than those of the control, showing a strong absorption capacity. In terms of disease occurrence, due to reasonable dense planting and sufficient nutrients, the overall stress resistance of the plants is improved, and the incidence of leaf spot and root rot is about 5 percentage points lower than that of the control. Economic benefit analysis shows that the dense planting and fertilization demonstration field increased income by about 100 yuan per mu, and the income increased without significantly increasing the input cost (part of the slow-release fertilizer replaced the conventional fertilizer dosage). The Zhumadian case proves that the implementation of dense planting + optimized fertilization in the main peanut producing areas can effectively break through the traditional yield bottleneck and achieve stable and high yields, which is very attractive to farmers. At present, this technology is also being gradually promoted in other counties and cities in Henan Province, and is welcomed by large-scale growers. 5.2 Example of soybean dense planting and fertilization yield increase in Qiqihar, Heilongjiang Qiqihar is located in the cold black soil area of Northeast my country and is a traditional soybean planting area and soybean breeding base in China. The local climate is cold and the frost-free period is short, and most soybean
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