Capim-braquiária adubado com diferentes proporções de fosfato natural e reativo em solos distintos

Abstract

The experiment was carried out in a greenhouse at Universidade Estadual de Montes Claros (UNIMONTES) in Janauba-MG, from 11 April 2012 to 25 July 2012, in order to evaluate morphogenesis, structural characteristics and forage yield of Brachiaria grass fertilized with different doses of reactive and natural phosphate on distinct soils . The experimental design was in randomized blocks (RBD) in a 2 x 6 factorial scheme, being two types of soil (acid and neutral) and six ratios between single superphosphate (SS) and Nature phosphate apatite (NP), with three replications, totaling 36 units and 12 experimental treatments. The following rates of reactive and natural phosphate were evaluated: 100 % NP; 20 % SS + 80 % NP; 40% SS + 60 % NP; 60% + 40% SS NP; 80 % SS + 60 % FN and 100 % SS. Phosphorus fertilization of all of the treatments was adjusted to 200 kg / ha of P2O5. The experimental units were constituted of plastic pots with capacity of 8 dm3 soil. They were evaluated the leaf appearance rate, phyllochron, leaf elongation rate, elongation pseudoculm rate, final length of the leaf blade, number of alive leaves, number of tillers, plant height, root weight and dry matter production in three evaluative cuts at 35, 70 and 105 days after uniform cut. With the dosage of 200 kg P2O5 / ha, the neutral soil presented better results than the acid soil for morphogenic and productive characteristics. The different proportions of natural phosphate and single superphosphate did not affect the morphogenetic characteristics nor root production, neither on acid soil nor on neutral one. For tillering and dry matter production, it was verified effect of different proportions of phosphorus sources.