Chiseling and gypsum application affecting soil physical attributes, root growth and soybean yield

ABSTRACT This study aimed to evaluate the effect of chiseling and gypsum application on soil physical properties, soybean root growth and grain yield. An experiment was carried out in Londrina, Paraná state, Brazil, under a randomized complete block design, with six replications. The soil in the experimental area is classified as a dystroferric Red Latosol (Oxisol), containing 720 g kg-1 of clay. The experiment comprised four treatments: (1) continuous no-tillage (CNT) system without gypsum application, (2) CNT with gypsum application at 3.5 Mg ha-1, (3) chiseled soil without gypsum, and (4) chiseled soil with gypsum application. Regardless of gypsum application, chiseling increased water infiltration rate in soil and reduced penetration resistance. Gypsum application affected neither water infiltration nor soil penetration resistance in both no-tillage (NT) and chiseled soil systems. Moreover, gypsum application improved soybean root development at a depth range of 0.20-0.40 m in NT system. Chiseling increased root growth in the surface layer (0-0.20 m depth). Either isolated or combined, chiseling and gypsum application had no impact on soybean grain yield throughout one cropping season.

摘要
本研究旨在评估凿耕与石膏施用对土壤物理性质、大豆根系生长及籽粒产量的影响。试验于巴西巴拉那州隆德里纳开展，采用随机完全区组设计，设置6次重复。试验区域土壤被归类为铁质暗色红Latosol（dystroferric Red Latosol，Oxisol，氧化土），黏粒含量为720 g·kg⁻¹。试验共设置4组处理：（1）无石膏施用的长期免耕（continuous no-tillage，CNT）体系；（2）以3.5 Mg·ha⁻¹用量施用石膏的长期免耕（CNT）体系；（3）未施用石膏的凿耕土壤；（4）施用石膏的凿耕土壤。无论是否施用石膏，凿耕均可提升土壤水分入渗速率，并降低土壤穿透阻力。在免耕（no-tillage，NT）与凿耕土壤体系中，石膏施用均未对土壤水分入渗速率及穿透阻力产生显著影响。此外，在免耕体系中，石膏施用可促进0.20~0.40 m土层内的大豆根系发育。凿耕则提升了表层土壤（0~0.20 m深度）的根系生长量。无论是单独施用还是联合应用凿耕与石膏措施，单季种植周期内均未对大豆籽粒产量产生显著影响。