协同作物提质增效和土壤地力提升的最佳氮素有机替代比例探索——以攀枝花芒果为例

晚熟芒果是攀枝花市重要的支柱产业,但近年由于生产中重化肥轻有机肥,导致果园质量退化,酸化现象严重、芒果品质下降。在前期研究和调研的基础上,根据攀枝花晚熟芒果及果园土壤的特点,选择了低、中、高3个肥力等级的芒果园,通过两年田间试验探索了晚熟芒果在不同氮素有机替代比例及优化施肥技术的作物产量、品质及土壤地力提升效果。结果表明：1）总体来说,当氮素有机替代比例为40%时,所有果园芒果产量和果实品质最佳,产量和氮肥偏生产力显著高于传统、氮磷钾优化及100%全量替代处理,Vc含量显著高于其他处理。而替代比例为100%时,低肥力和高肥力果园产量显著下降,氮肥偏生产力显著低于其他替代比例处理,同时会导致土壤磷养分的过量累积。2）随着替代比例的升高,土壤有机质含量增加,土壤pH增加。通过主成分分析得出,各处理的土壤地力水平,随着有机替代的比例增加而逐渐增加,替代比例为100%时,综合得分最高,其次是部分替代处理,传统施肥和优化施肥处理低于有机替代处理。3）综合作物产量、品质及土壤地力,不同土壤肥力下最佳的有机替代比例不同,低肥力和高肥力土壤短期内有机替代比例不宜较高,否则产量显著下降。通过芒果的产量、品质、土壤地力水平等因素综合分析,攀枝花晚熟‘凯特'芒果最优氮素有机替代比例为40%,替代比例过低无法有效提高土壤地力并改善作物品质,而替代比例过高容易导致养分供给不足,作物减产,特别是在土壤养分含量及有机质较低的低肥力果园,由于土壤保肥能力低,须在增施有机肥的同时保证充足的无机养分供应,着重碳氮协同优化。

Optimal Nitrogen Organic Replacement Ratio for Synergistic Crop Quality and Efficiency Enhancement and Soil Fertility Enhancement- Taking Panzhihua Mango as an Example

Late-ripening mango is an important pillar industry in Panzhihua. In recent years, due to heavy chemical fertilizer application and light organic fertilizer application, the orchard quality degrades, acidification phenomenon is serious and mango quality declines. In this paper, on the basis of research and investigation, according to the characteristics of the mature mango orchard soil in Panzhihua, low, medium and high fertility level of mango orchards were treated with different nitrogen organic replacement ratio for two years to optimize the fertilization technology for crop yield, quality and soil fertility promotion effect. In general, the fruit yield and fruit quality were the best in all orchards when the nitrogen organic replacement ratio was 40%, significantly higher than those of traditional, NPK optimization and 100% total replacement treatments, and the Vc content was significantly higher than those in other treatments. When the replacement ratio was 100%, the yield of low-fertility orchards and high-fertility orchards decreased significantly, and nitrogen partial productivity was significantly lower than that of other replacement ratios, which also resulted in excessive accumulation of soil phosphorus. Soil organic matter content and soil pH increased with the increase of substitution ratio. Through principal component analysis, the soil fertility level of each treatment increased gradually with the increase of the proportion of organic replacement. When the proportion of organic replacement was 100%, the comprehensive score was the highest, followed by the partial replacement, and the traditional and optimized fertilization treatments were lower than than those of the organic replacement treatments. Considering crop yield, quality and soil fertility, the optimal ratio of organic replacement was different under different soil fertility. Low and high fertility soil should not have a high ratio of organic replacement in the short term, otherwise the yield would decrease significantly. By yield, quality, comprehensive analysis of the factors such as soil fertility levels, the organic replacement ratio of Panzhihua late ‘Keitt' mango is 40%, too low organic replacement ratio can't effectively improve the soil fertility and improve fruit quality, and high replacement ratio can easily lead to crop failures in nutrient supply, especially in orchards of low content of soil nutrients and organic matter. Due to the low capacity of soil fertilizer conservation, it is necessary to ensure sufficient inorganic nutrient supply while increasing organic fertilizer application, and emphasizing the coordinated optimization of carbon and nitrogen.