Chemical attributes of a silvopastoral system with a legume tree and signal grass in the Brazilian savanna
Chemical attributes of a silvopastoral system with a legume tree and signal grass in the Brazilian savannawca2014-1823 Rodrigo M. A. D. Mendonca 1,*Angela M. Q. Lana 1Regina M. Q. Lana 2Iran Borges 1Jose P. Lemos Filho 3Rayanne S. Souza 1 1Animal Science, Universidade Federal de Minas Gerais, Belo Horizonte, 2Agronomy Science Institute, Universidade Federal de Uberlandia, Uberlandia, 3Biological Science Institute, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
Brazil is the world’s biggest meat exporter; more than 40% of beef production takes place in the Brazilian savanna pastures. The research site was located in Southeastern Brazil (20º18’16.71”S; 44º55’28.57” W) and had 35.3 ha of silvopasture (SP) with signal grass (Urochloa brizantha) and native legume tree, Pterodon emarginatus,with a density of 156 trees ha-1 established more than 30 years as cattle pasture never fertilized. The control (CT) had 26.5 ha traditional signal grass pasture. Soil collection profiles were made randomly at both areas at 0-10, 10-20, 20-40, 40-100 and 100-140 cm deep, in order to study the chemical attributes and the influence of a stabilized silvopasture. Calcium (Ca+2) was higher (P<0.05) in the CT, compared to SP area at 0-10, 10-20cm profiles, but no difference was found in other layers. Inside SP, Ca+2 in 0-10 cm was higher (P<0.05) than 10-20 and 100-140cm, while intermediate values where found at 20-100 cm profiles. Variables P M1, K+, S-SO4=, Zn, B and Sum of Bases (SB) did not show differences between systems (P>0.05), but Organic Carbon (OC), Cu and Fe were higher at SP, while Water pH had superior values in the CT(P<0.05). OC, Fe e P showed decreasing differences (P<0.05) with increasing of depth for both systems. Al, Cu and B were higher (P<0.05) down to 40 cm deep and reduced from this layer. Levels of Zn and SB were higher (P<0.05) at 0-10cm and kept the same values in other depths. Sulfur was higher in 0-10cm in comparison to100-140cm depth (P<0.05), but the other profiles were intermediate. Non-fertilized silvopastoral system with native legume trees adapted to poor acid soil, had higher carbon content than traditional pasture, however, there was extraction of most of the nutrients.