ABSTRACT

A long-term experiment was initiated in a sub-humid tropical Indian rice-wheat system to identify suitable soil quality indicators for determining yield and sustainability of the system as influenced by chemical fertilizers (NPK) alone or in combination with organic amendments viz. farmyard manure (FYM), paddy straw (PS) and green manure (GM). Soil samples were analysed for physical, chemical and biological indicators after 30 crop cycles and the soil quality index (SQI) was calculated by nonlinear scoring functions following the methodology of principal component analysis and multiple regression analysis-based minimum data set selection. Application of NPK fertilizers in combination with FYM and GM significantly increased systems yield and sustainability (sustainable yield index or SYI) as well as improved soil properties compared to the control and other combinations. The value of the dimensionless SQI varied from 2.0 in the control plot to 3.1 in the NPK+FYM. A greater SYI and SQI in the NPK+FYM treatment suggested that FYM in combination with chemical fertilizers has an edge over GM and PS. Among all the indicators (30) under study, available-N, soil organic carbon, available-B and aryl-sulfatase were screened as suitable indicators which contributed 24, 29, 24, 22%, respectively to the SQI in NPK+FYM treatment.

摘要

在亚湿润热带印度稻麦系统中启动了一项长期实验，以确定合适的土壤质量指标，以确定该系统的产量和可持续性，这些指标仅受化学肥料 (NPK) 的影响或与有机改良剂（即有机肥）的结合。农家肥（FYM）、稻草（PS）和绿肥（GM）。对30个作物周期后的土壤样品进行物理、化学和生物指标分析，并按照主成分分析和基于多元回归分析的最小数据集选择方法，通过非线性评分函数计算土壤质量指数（SQI）。与对照和其他组合相比，NPK 肥料与 FYM 和 GM 结合使用可显着提高系统产量和可持续性（可持续产量指数或 SYI）以及改善土壤性质。无量纲 SQI 的值从控制图中的 2.0 变化到 NPK+FYM 中的 3.1。NPK+FYM 处理中更大的 SYI 和 SQI 表明 FYM 与化肥的组合优于 GM 和 PS。在研究的所有指标（30个）中，速效氮、土壤有机碳、速效B和芳基硫酸酯酶被筛选为合适的指标，它们分别对NPK+FYM处理的SQI贡献了24%、29%、24%、22% . NPK+FYM 处理中更大的 SYI 和 SQI 表明 FYM 与化肥的组合优于 GM 和 PS。在研究的所有指标（30个）中，速效氮、土壤有机碳、速效B和芳基硫酸酯酶被筛选为合适的指标，它们分别对NPK+FYM处理的SQI贡献了24%、29%、24%、22% . NPK+FYM 处理中更大的 SYI 和 SQI 表明 FYM 与化肥的组合优于 GM 和 PS。在研究的所有指标（30个）中，速效氮、土壤有机碳、速效B和芳基硫酸酯酶被筛选为合适的指标，它们分别对NPK+FYM处理的SQI贡献了24%、29%、24%、22% .