Spatial variability of soil physical attributes in integrated production systems in the Amazon region

Abstract: The objective of this work was to analyze the spatial variability of soil physical attributes in integrated production systems and its relationship with the growth and yield of a corn (Zea mays) crop intercropped with palisade grass (Urochloa brizantha). The experiment was carried out in an integrated crop-livestock (ICL) system and in an integrated crop-livestock-forestry (ICLF) system, in a Plinthic Hapludox. The ICLF system was managed in alleys between eucalyptus (Eucalyptus spp.) rows, spaced at 18, 30, and 42 m. Corn grain and forage yields were positively correlated with soil clay and moisture contents, whereas grain yield was negatively correlated with soil penetration resistance. The lowest corn plant heights and grain yields were observed near eucalyptus rows. The average values for soil penetration resistance were below 2.0 MPa. Spatial variability was verified for: corn plant height, grain yield, and agronomic efficiency; forage intercropping; and soil moisture and silt contents, as well as penetration resistance. Greater grain and biomass yields were obtained at a 42-m distance between tree rows. The obtained results are indicative that corn traits and soil physical attributes were only slightly associated. The spatial distribution of the eucalyptus rows influences the agronomic efficiency of the intercrop and soil moisture contents.

摘要：本研究旨在分析综合生产系统中土壤物理属性的空间变异特征，及其与间作巴拉草（Urochloa brizantha）的玉米（Zea mays）作物生长和产量的关联关系。试验分别在网纹典型湿润老成土（Plinthic Hapludox）上的农牧综合系统（integrated crop-livestock, ICL）与农-牧-林综合系统（integrated crop-livestock-forestry, ICLF）中开展。其中ICLF系统设置于桉树（Eucalyptus spp.）行带间的林隙内，桉树行距分别设置为18 m、30 m和42 m。研究结果显示，玉米籽粒与饲草产量与土壤黏粒含量、土壤含水率呈显著正相关，而籽粒产量与土壤穿透阻力呈显著负相关。在桉树行带附近区域，玉米株高与籽粒产量均处于最低水平。土壤穿透阻力的平均值低于2.0 MPa。本研究验证了以下指标存在空间变异：玉米株高、籽粒产量与农艺效率；饲草间作相关指标；土壤含水率、粉粒含量以及土壤穿透阻力。当桉树行距为42 m时，可获得更高的籽粒与生物量产量。结果表明，玉米相关性状与土壤物理属性的关联度较弱。桉树行带的空间分布会影响间作系统的农艺效率与土壤含水率。