Identification of key soil properties is an essential prerequisite to delineating the management zone (MZ), which is traditionally done by selecting soil parameters before crop planting. However, soil properties during sensitive stages of crop growth may have a greater effect on the MZ delineation than those before planting. This study is aimed to determine whether inclusion of soil properties measured in surface layers during the reproductive stage of rice could enhance the appropriateness of MZ delineation based on sodic/saline-sodic paddy fields. When including soil variables during the reproductive stage, with/without soil variables before planting, a similar MZ pattern (MZ pattern 3) was generated. Furthermore, when including soil variables during the reproductive stage and rice yield components, with/without soil variables before planting, another similar MZ pattern (MZ Pattern 4) was generated. Compared with other patterns, the MZ pattern 4 showed higher relative variances for rice yield and the mean of its most important yield-influencing factors, with lower coefficient of variation (CV) in all MZs compared with the whole-paddock CV. Likewise, this pattern showed improvement in discriminating soil and rice variables among MZs. These findings confirm that inclusion of soil properties during the reproductive stage of rice has potential for enhancing the appropriateness of MZ delineation. This study also necessitates inclusion of carbonate-derived variables when delineating MZs in sodic/saline-sodic paddy fields. Our results encourage further investigation of the role of soil properties in surface soil layers at critical crop growth stages in MZ delineation under multiple soil and climatic conditions.

中文翻译：

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基于大田水稻生殖期土壤性质测定的管理区划定

确定关键土壤特性是划定管理区 (MZ) 的必要先决条件，传统上这是通过在作物种植前选择土壤参数来完成的。然而，与种植前相比，作物生长敏感阶段的土壤特性对 MZ 划分的影响可能更大。本研究旨在确定在水稻生殖阶段纳入表层测量的土壤特性是否可以提高基于钠/盐碱水田的 MZ 划分的适当性。当在繁殖阶段包括土壤变量时，在种植前有/没有土壤变量，生成了类似的 MZ 模式（MZ 模式 3）。此外，当包括生殖阶段的土壤变量和水稻产量成分时，种植前有/没有土壤变量，生成了另一个类似的 MZ 模式（MZ 模式 4）。与其他模式相比，MZ 模式 4 的水稻产量及其最重要的产量影响因素的平均值显示出更高的相对方差，与整个围场 CV 相比，所有 MZ 的变异系数 (CV) 较低。同样，这种模式表明在区分 MZ 之间的土壤和水稻变量方面有所改进。这些发现证实，在水稻生殖阶段纳入土壤特性有可能提高 MZ 划分的适当性。本研究还需要在描绘钠/盐碱稻田中的 MZ 时包括碳酸盐衍生变量。