地形和土壤属性对大豆产量的影响

正确理解作物产量的变异性特征及其影响因素是对农田地块进行科学管理的基础。地块的地形特征是导致作物产量变异形成的主要因素。本文选择代表不同地形特征的洼地农田和岗地农田为研究对象,分析地形对土壤属性和大豆产量的影响以及它们之间的相互关系。研究结果显示,洼地农田与岗地农田的土壤属性和大豆产量均存在显著性差异(P<0.05)。洼地农田的土壤养分含量较高,但土壤结构较差,其平均重量直径(MWD)和几何平均直径(GMD)显著小于岗地农田,质量分形维数(Dm)显著大于岗地农田;在两类农田地块中,大豆产量的差别较大,洼地农田的大豆产量仅为岗地农田的62%。相关性分析表明,大豆产量与土壤结构稳定性和地块高程呈极显著正相关(P<0.01);土壤有机碳和土壤养分对大豆产量没有显著影响。

Soybean Yields Related to Topography and Soil Properties

Understanding the variability of crop yields and its affecting factors is an important issue in agricultural research. The objective of this study was to characterize the effects of topography and soil properties on variability of soybean yields in the Mollisols region fields. The results showed that there were significant differences in soil properties and soybean yields between the lowland and upland fields. Compared to the upland fields, the lowland fields had significantly (P<0.05) higher soil organic carbon and soil nutrients content. Obviously smaller mean weight diameter (MWD) and geometric mean diameter (GMD), and greater mass fractal dimension (Dm) on the lowland fields suggested that the lowland fields had worse soil structure than that in upland fields. Soybean grain yield and biomass on the lowland fields were significantly (P<0.05) lower with comparison to the upland fields, and there was no significant difference in harvest index between them. The results of correlation analysis indicated that a significant positive relationship was found between soybean yields and fields relative elevation. There was significant correlation between soybean yields and soil structure stability. Soybean yields gave a significant positive relationship with MWD and GMD, and a significant negative relationship with Dm. Soil organic carbon, total nitrogen and available nitrogen showed no influence on soybean yields.