Chemical attributes of agricultural soil after the cultivation of cover crops

Abstract

The use of cover crops is a strategy to maintain the productive capacity of agricultural soils. The increase of organic carbon content, nutrient cycling and, consequently, the increase in soil fertility are some of the greatest benefits. This study evaluated the chemical attributes of the soil after the use of cover crops species in the Cerrado region of Piaui. The experiment was carried out from January 2015 to July 2016. It was performed in a completely randomized block design with eleven treatments and four replicates. The treatments consisted of six species of Fabaceae, two of Poaceae, two-component intercrops and spontaneous vegetation (control). The soil chemical analyses were performed 14 months after the implantation of the cover crop species. The following soil horizons were evaluated: 0.0-0.10; 0.10-0.20 and 0.20-0.40 m. The values of phosphorus (P), potassium (K+), calcium (Ca2+), magnesium (Mg2+), aluminum (Al3+), potential acidity (H + Al), soil organic carbon (OC), the saturation of bases (V%), saturation by aluminum (m%) and effective CEC were measured. Fifteen months after their establishment, cover crops positively influenced the levels of P, K and OC with no changes in the other chemical properties. The OC contents were higher with the use of C. cajan - cv. 'fava larga', brachiaria and C. ochroleuca + millet, mainly in the topsoil. C. espectabilis, spontaneous vegetation, M. aterrima, brachiaria and C. ochroleuca were the most efficient in K cycling.