Sistemas de manejo do solo e de produção de algodão, soja e milho em solo arenoso do cerrado da Bahia

The objectives of this study are to evaluate tillage and crop systems on soil fertility, soil carbon stock changes at depth and yield performance of soybean, cotton, and maize grown in the sandy soil of western Bahia, Brazil. Four treatments consist of conventional tillage and monocropping of Gossypium hirsutum L. r latifolium, soybean, and corn; and six treatments with these cash crops rotations with Urochloa ruziziensis (ruzigrass) and Sorghum bicolor as cover crops, and Crotalaria ochroleuca as a green manure, under no-tillage. Each experimental plot measure 400 m2 (20 m x 20 m). Cotton, soybean, and maize are harvest at three random points, each composed of 4 rows of 5 m in length. The experimental design was a randomized block design with four replicates. Soil samples are collected at three depth intervals (0-10 cm, 10-20 cm and 20-40 cm), and in some years until 40-60 cm and 60-100 cm. "Soil samples are collected at three depth intervals (0-10 cm, 10-20 cm and 20-40 cm), and in some years until 40-60 cm and 60-100 cm. pH in water (soil:water = 1:2.5); available phosphorus and exchangeable potassium, extracted by Mehlich-1; exchangeable calcium and magnesium, extracted by KCl 1mol L-1; potential acidity, extracted by calcium acetate, 0.5 mol L-1, pH 7.0; soil organic matter (by wet combustion followed by colorimetric determination)" From the beginning of the experiment until 2017, soil organic carbon concentration was measured by wet combustion followed by colorimetric determination. The SOC concentration, expressed on a volumetric basis, was converted to a gravimetric basis according to the pedotransfer function, using the total sand concentration. After 2018 soil organic carbon was determined by dry combustion in a C and N elemental analyzer (Perkin Elmer Elemental Analyzer 2400 Series II) according to the Pregl-Dumas method (Nelson & Sommers 1996). Soil samples are collected at three depth intervals (0-10 cm, 10-20 cm and 20-40 cm), and in some years until 40-60 cm and 60-100 cm. Soil bulk density was determined using a volumetric ring. Soil samples are collected at three depth intervals (0-10 cm, 10-20 cm and 20-40 cm), and in some years until 40-60 cm and 60-100 cm. Soil mineralogy was not performed. Granulometry corresponding to 463, 143 and 394 g kg-1 of clay, silt and sand, respectively. Soil samples were subjected to the BioAS method.