2.1 Site description
This study was performed in areas of soybean cultivation in the southern area of the state of Mato Grosso in the Cerrado region, Brazil. By Koppen classification, the climate of study region is classified as type Aw with dry winters. The average rainfall remains 1300-1600 mm per year, the annual average temperature is 24-26 °C, and the average regional altitude is 400-500 m a.s.l. (Alvares et al., 2013). The studied areas are covered by Oxisols (Latosols) (Santos Et al., 2018).
In this study, the 65 farms, dominant by soybean cultivation under a long-term NT system, were sampled. The cultivation system is characterized as soybean in the summer and maize (Zea mays ) during the second season. However, cover crops, including Crotalaria (Crotalaria juncea ), millet (Panicum miliaceum ) or Brachiaria (Brachiaria mutica ) are also being rotated with the second season’s crop. Furthermore, intercropping of Brachiaria in maize was practiced over an approximately 20% of the study area during last five years.