Soil organic carbon stock is improved by cover crops in a tropical sandy soil

Abstract

Soil organic matter plays an important role in soil quality. In sandy soils of tropical regions, high biological activity in the soil accelerates mineralization and limits increases in organic matter content. The objective of this study was to evaluate the total organic C stock and the chemical and physical fractions of organic C in a sandy soil in Presidente Bernardes, São Paulo, Brazil, as a function of cover cropping with different combinations of grasses and legumes between 2015 and 2020. The treatments comprised fallow (control), cultivation of a single grass or intercropping of two grasses, one grass and one legume, or a mixture of two grasses and one legume during the offseason (April-September). Intercropping two grasses increased total dry matter production (shoot and root) by 138% and decreased the C/N ratio by 19% compared with the fallow and legume systems. The organic C stock in the soil was 46% higher in the mixed cover crop system (36.5 Mg ha −1 ) than in the fallow system (25 Mg ha −1 ). Humic acid (0.78-0.82 g kg −1 ) and humin (1.68-1.99 g kg −1 ) were lower in the systems with low dry matter production (fallow and grass + legume). Mineral-associated C content was 114% higher in the mixed cover crop system than in the fallow system. These results show that cover crops can increase C content in all fractions of organic matter in tropical sandy soil, even in a short period of time (5 yr), and that a mix of cover crops is the best option.

Influence of various intercropping systems on soil quality characteristics and their potential for climate change adaptation in Dedza, Malawi

“…contents varied in all cereal-legume intercropping combinations. The results concur with Cordeiro et al [21], who reported increased soil particulate organic content due to intercropping. The Results of this study included the following, from the largest to the lowest: millet and beans (8.92%), millet and soya (8.85%), millet and groundnuts (6.57%), millet sole (7.66%), local orange maize and soya (6.20%), sorghum and groundnuts (6.05%), sorghum sole (5.74%), local orange maize sole (5.54%), sorghum and beans (5.22%), local orange maize and beans (4.65%), sorghum and soya (4.36%), and local orange maize and groundnuts (4.23%) (Fig.…”

Three years of cover crops management increased soil organic matter and labile carbon pools in a subtropical vegetable agroecosystem

“…In addition, biomass was not significantly correlated with SOM (Figure 2), which could be partially due to high spatial heterogeneity of soil properties masking trends among different treatments (Figure 4). These results further highlight that keeping soil covered continuously could be more important than selecting certain species or mixtures in terms of building SOM and soil health (Calegari et al, 2008;dos Santos Cordeiro et al, 2022).…”

Influence of tillage and residue management practices on productivity, sustainability, and soil biological properties of rice-barley cropping systems in indo-gangetic plain of India

“…The MBC is one of the most labile of the carbon pools comprising organic matter, which varies with different management practices (Zhang et al, 2021 ; Cordeiro et al, 2022 ). Nutrient availability potential represents an increase in MBC than an increase in total organic matter (Sharma et al, 2022b ).…”