西南紫色土不同施肥措施下土壤综合肥力评价与比较

【目的】 为探求长期不同施肥处理对作物产量的影响和土壤综合肥力的演变,寻求合理评价西南紫色土区域土壤综合肥力的方法。 【方法】 本研究以7年的定位试验的数据为基础,运用内梅罗指数法、相关系数法和因子分析法对不施肥对照 (CK)、化肥优化施用 (OP)、在化肥优化基础上有机肥氮替代50%化肥氮 (MF)、在化肥优化基础上有机肥氮替代100%化肥氮 (OM) 4个处理的土壤肥力进行综合评价。 【结果】 不同施肥处理下蔬菜和玉米的平均产量均表现为MF处理最大。在蔬菜季,MF处理显著提高了产量,相比OP和OM处理,榨菜分别增产27.8%和16.0%,大白菜分别增产28.6%和8.7%;在玉米季,MF处理的产量最大,为9907 kg/hm2,显著高于OP和OM处理,分别增产1199 kg/hm2和1273 kg/hm2。通过分析土壤单项肥力指标与作物产量的相关关系表明,土壤有机质、全氮和有效磷与作物产量均存在显著或极显著正相关关系,表明土壤有机质、全氮和有效磷对紫色土土壤肥力贡献大,是表征紫色土土壤肥力的重要指标。用3种评价方法计算的不同施肥处理的土壤综合肥力指数值 (IFI) 均表现为OM > MF > OP > CK,施用有机肥处理 (MF和OM) 处理IFI值要显著高于优化施肥处理。3种评价方法的IFI值与作物产量均呈显著或极显著关系,但3种评价方法的相关系数平均值从大到小表现为相关系数法 (0.5292) > 内梅罗指数法 (0.5252) > 因子分析法 (0.5130),表明相关系数法比内梅罗指数法和因子分析法更可靠。 【结论】 在蔬菜?玉米轮作体系下,有机肥氮替代部分化肥氮能增加作物产量,提高土壤综合肥力水平。从3种评价方法的精确性来看,相关系数法比内梅罗指数法和因子分析法更可靠,在实践中优先使用。

Evaluation and comparison of integrated purple soil fertility under different fertilizations in Southwest China

【Objectives】 In order to explore long-term effect of different fertilization treatments on crop yields and evolution of soil fertility, a reasonable integrated evaluation method of soil fertility was studied in this paper. 【Methods】 The study was based on a 7-years’ localized fertilization experiment in the purple soil in the southwest of China. The treatments included non-fertilization (CK), optimal fertilization (OP), organic N replace 50% chemical N (MF) and organic N replace 100% N (OM). The crop yields were investigated, and the soil physic-chemical properties were measured. The methods of Nemoro index, correlation coefficient and factor analysis were respectively used to calculate values of the integrated soil fertility index (IFI) under each treatment, the accuracy of the three methods were compared. 【Results】 The average yields of vegetables and corn of the MF were the highest among the fertilization treatments. In the vegetable season, the MF treatment significantly increased the yield. Compared with the OP and OM treatments, the mustard yields were increased by 27.8% and 16.0%, respectively, and the Chinese cabbage yields were increased by 28.6% and 8.7%, respectively. In the maize season, the maximum yield of the MF treatment was 9907 kg/hm2, and increased by 1199 kg/hm2 and 1273 kg/hm2 compared with the OP and OM treatments, respectively. By analyzing the correlations between individual soil fertility index and crop yields, there were significant or extremely significant positive correlations between soil organic matter, total nitrogen, available phosphorus and crop yields, indicating that soil organic matter, total nitrogen and available phosphorus contributed significantly to soil fertility in purple soil and were important indicators to characterize soil fertility in purple soil. The IFI was in the order of OM > MF > OP > CK under three evaluated ways, and the IFI value of the application organic manure was significantly higher than that of the OP treatment. The IFI values of the three evaluation methods showed significant or extremely significant relationship with crop yields, but the mean of the correlation coefficients of the three evaluation methods were in the order of the correlation coefficient method (0.5292) > the Nemoro index method (0.5252) > the factor analysis method (0.5130), indicating that the correlation coefficient method was more reliable than the Nemoro index method and the factor analysis, and was preferred in practice. 【Conclusions】 In vegetable and maize rotation system, the replace part of chemical nitrogen with organic nitrogen can increase crop yields and improve the integrated soil fertility level. From the accuracy of the three evaluation methods, the correlation coefficient method is more reliable than the Nemoro index and factor analysis method, and is preferred in practice.