Effects of the mechanical chiseling in the soil physical and agronomical attributes in an elephant grass crop

ABSTRACT Soil compaction is one of the major causes of yield losses in forage crops, especially those for the production of silage, due to heavy machinery traffic in seeding, management and harvesting operations. The soil chiseling could be an alternative to solve the problem. Thus, this work aimed to evaluate the effects of mechanical chiseling on the physical attributes in a Yellow Argisoil, and agronomic characteristics of elephant grass grown, in area with intensive traffic of machines. The experiment was conducted at the Campus of Agricultural Sciences - UNIVASF in the Submedium of the São Francisco River, in randomized blocks design with four replications; consisting of three depths chiseling: ESC 0 - without chiseling, ESC 15 - chiseling 0.00 to 0.15 m and ESC 30 - chiseling 0.00 to 0.30 m. It was evaluated the physical attributes of the soil before and after chiseling scarification, and soil bulk density, porosity and penetration resistance; and agronomical components of elephant grass: plant height and biomass production. The bulk density, porosity and resistance to penetration as well as biomass production were not affected by the depth of chiseling, due to the sand soil texture. The mechanical resistance to penetration proved to be the most sensitive attribute to identify the compacting and the effect of mechanical chiseling. It was not observed change in the soil physical properties in the treatments with chiseling, chiseling in the depth of 0.00 to 0.15 m and 0.00 to 0.30 m. The chiseling depth evaluated not affect the agronomical components of the elephant grass.

摘要：土壤压实是饲用作物产量损失的主要诱因之一，尤以青贮生产用饲用作物为甚，其成因在于播种、田间管理及收获作业中重型机械的碾压通行。土壤深松技术或是解决该问题的可行方案。本研究旨在评估机械深松对机械高频通行区域内黄色黏磐土（Yellow Argisoil）物理性状的影响，以及对种植于该区域的象草农艺性状的作用。试验于圣弗朗西斯科河中游区域的圣弗朗西斯科河谷联邦大学（UNIVASF）农业科学学院校区开展，采用随机区组设计，设置4次重复，共3种深松处理：ESC 0（无深松）、ESC 15（深松深度0.00~0.15m）、ESC 30（深松深度0.00~0.30m）。本研究分别测定了深松前后土壤的物理性状，包括土壤容重、孔隙度及穿透阻力；同时测定象草的农艺性状指标：株高与生物量产量。结果表明，由于供试土壤为砂质质地，深松深度对土壤容重、孔隙度、穿透阻力及象草生物量产量均无显著影响。土壤穿透阻力被证实是识别土壤压实状况及机械深松改良效果的最敏感指标。相较于无深松处理，0.00~0.15m与0.00~0.30m深松处理均未对土壤物理性状产生显著改变。本研究所考察的深松深度对於象草的农艺性状亦无显著影响。