Lime, phosphorous and molibdenum in a cerrado soil, for green-panic + galaxia growth

Abstract

A field experiment was carried out in a complete randomized block design in a cerrado soil classified as an Entisol to study the effects of phosphorus levels (30, 80 and 130 kg P₂0₅/ha), combined with lime (0 and 1.2 t/ha) and molibdenum (125 and 250 g Mo/ha) upon a grass-legume mixture (green-panic and Galactia striata). During two years, it was evaluated the dry matter yield (grass, legume and grass + legume) and the concentrations of crude protein, phosphorus, calcium, magnesium, potassium, zinc, copper and manganese in the grass and legume tissues. The increase in the molibdenum rates did not affect significantly any of these variables. The phosphorus rates increased linearly (p < 0.01) the legume herbage yield in the first and first plus second years. In the absence of lime phosphorus rates caused variations (p < 0.01) in the concentrations of phosphorus in the grass according to quadratic regressions in the first and in the second years. In the presence of lime the plant phosphorus concentration increased linearly with phosphorus fertilization. In the legume herbage the phosphorus concentration varied according to a quadratic regression (p < 0.01) in the first year and linearly in the second, independently of liming. Lime increased legume and grass plus legume dry matter yield in the first year and in tbe fi rst plus secondyears and in the legume in lhe second year. The phosphorus and lime rates influenced also almost all the othervariables studied.