Qualidade física e frações da matéria orgânica de um Planossolo sob sistema plantio direto

Abstract

Resumo -O objetivo deste trabalho foi avaliar a qualidade física e as frações da matéria orgânica de um Planossolo sob sistema plantio direto (SPD), com diferentes tempos de implantação, no Sul do Brasil. Amostras de solo foram coletadas nas camadas de 0,00-0,03, 0,03-0,06, 0,06-0,10 e 0,10-0,20 m, tendo-se determinado: a porosidade total (Pt); a macroporosidade (Ma); a microporosidade (Mi); a resistência do solo à penetração (Rp); a densidade (Ds); os macro e microagregados; o diâmetro médio ponderado dos agregados (DMP); o carbono orgânico total (COT); o carbono das frações leve livre (FLL), leve oclusa (FLO) e pesada (FP); os estoques de carbono (EstC), os índices de labilidade (ILC), de estoque (IEC) e de manejo do carbono (IMC). O tempo de implantação SPD aumentou a Pt, a Ma, os EstC, e diminuiu a Mi, a Rp e a Ds. O SPD promove os atributos DMP, ILC, IEC e IMC a partir do quinto ano de implantação, e, portanto, melhora a qualidade física do solo.Termos para indexação: dinâmica da matéria orgânica, estruturação do solo, fracionamento da matéria orgânica, índices de labilidade, solo hidromórfico, solos de várzea. Physical quality and organic matter fractions of an Alfisol under no-tillageAbstract -The objective of this work was to evaluate the physical quality and the organic matter fractions of an Alfisol soil under no-tillage (NT) with different deployment times in Southern Brazil. Soil samples were taken at the 0.00-0.03, 0.03-0.06, 0.06-0.10, and 0.10-0.20-m depths, for determining: total porosity (Pt); macroporosity (Ma); microporosity (Mi); soil penetration resistance (Rp); bulk density (Ds); macro-and microaggregates; mean weight diameter (MWD) of soil aggregates; total organic carbon content (TOC); the free light (FLL), light occluded (FLO), and heavy (FP) carbon fractions; carbon stocks (EstC); and the lability (ILC), stock (IEC), and carbon management (IMC) indexes. SPD deployment time increased Pt, Ma, and EstC, and decreased Mi, RP, Ds. NT promotes MWD, ILC, IEC, and IMC after five years of deployment, and, therefore, it improves soil physical quality.

Visual Evaluation of the Soil Structure under Different Management Systems in Lowlands in Southern Brazil

“…Therefore, one of the alternatives to maximize agricultural yields as well as promote soil quality would be the adoption of no-tillage and crop livestock integration systems. Systems such as no-tillage can also induce reductions in greenhouse gas emissions (Ball et al, 2013;Silva et al, 2014), and increase carbon stocks and microbial diversity in the soil (Reis et al, 2016), mainly by the accumulation of surface crop residues.…”

“…If only higher yields are pursued, the soil structural quality may be compromised, with negative effects on agricultural sustainability in the long term. According to Reis et al (2016), management systems including vegetation cover and control of soil disturbance and machinery traffic, such as the no-tillage system, can benefit soil physical properties in lowlands.…”

Organic Matter Fractions and Carbon Management Index in Oxisol Under Integrated Agricultural Production Systems

“…It is possible to emphasize that the evaluated management contributed to the maintenance of the soil carbon contents. However, it is worth noting that the efficiency of a system in the recovery of soil quality depends, besides the characteristics of this management, on the degradation process of the soil, such as overpasses, soil exploitation and low production of residues (Reis et al, 2016;Isernhagen et al, 2017).…”

Soil Physical Attributes in Long-Term Soil Management Systems (Tillage and No-till)

“…This system improves soil strength to support traffic without presenting significant compressibility due to denser and resistant aggregates (Stone et al, 2006). Reis et al (2016) and Torres et al (2019) observed that the reductions in soil density and soil compaction were related to increments of soil porosity in areas cultivated under NTS with increasing periods of system implantation.…”