Chemical composition of cover crops and soil organic matter pools in no‐tillage systems in the Cerrado

• Published in: Soil use and management Vol. 38; no. 1; pp. 940 - 952
• Main Authors: Carvalho, Arminda Moreira, Ribeiro, Luana Ramos Passos, Marchão, Robélio Leandro, Oliveira, Alexsandra Duarte, Pulrolnik, Karina, Figueiredo, Cícero Célio
• Format: Journal Article
• Language: English
• Published: Bedfordshire Wiley Subscription Services, Inc 01-01-2022
• Subjects: Accumulation; Agricultural practices; Canavalia brasiliensis; Cellulose; Chemical composition; Corn; Cover crops; Crop production; Crop yield; Crops; Dry matter; Hemicellulose; hemicelluloses; labile carbon; Lignin; nitrogen; Organic matter; Organic soils; Soil; Soil organic matter; Soils; Sorghum; Stocks; Tillage; Total organic carbon; Urochloa ruziziensis
• ISSN: 0266-0032; 1475-2743
• DOI: 10.1111/sum.12746

In no‐tillage systems (NTS), cover crops are recommended to increase the productivity of agricultural systems. Furthermore, a greater diversity of cover crops in NTS favours an increase in soil carbon (C) stocks. However, there are scarce published data on the relationship between the chemical composition of cover crops and the accumulation of labile and stable fractions of SOM. We evaluated the relationship between the chemical composition of cover crops and SOM fractions, C stocks and maize yield. Hemicellulose, cellulose and lignin contents were determined for Urochloa ruziziensis, Canavalia brasiliensis, Cajanus cajan and Sorghum bicolor, cultivated in the off‐season of maize. Canavalia brasiliensis had high N (20.96 g kg−1) and hemicellulose (185.67 g kg−1) contents, lower lignin content (39.50 g kg−1) and high dry matter yield (3,251 kg ha−1). All these characteristics resulted in a better SOM quality. Urochloa ruziziensis, with higher hemicellulose and lower lignin contents, and low lignin/N ratio, was associated with accumulation of TOC (19.95 and 18.33 g kg−1 in 0‐ to 10‐cm and 10‐ to 20‐cm layers, respectively) and mineral‐associated organic C (on average, 16.68 g kg−1) in the soil. Cover plants with N:lignin ratio lower than 2.0 are fundamental for soil C sequestration. In conclusion, it is recommended the adoption of Urochloa ruziziensis and Canavalia brasiliensis as cover plants improve maize production, soil organic matter quality and C sequestration in the Cerrado region.