Chemical Attributes of a Typic Acrudox Soil on Marandu Palisade Grass under Rotational Stocking, Liming and Nitrogen Fertilisation

摘要

Urochloa brizantha (synonymous of Brachiaria) is the most spread species of grass in the tropical world, primarily in regions with acid and low fertility soils. This study was conducted to investigate changes in the soil chemical properties of a Typical Acrudox submitted to a strategy of grazing with rotational stocking, liming and nitrogen fertilisation. Treatments involved combinations of two pre-grazing heights (25 and 35 cm) with two rates of nitrogen (50 and 200 kg·ha-1·year-1). All combinations received lime, P and K fertilization and an untreated control group was allocated according to a complete randomised block design, five replications. Soil sampling was done in layers of 0-5, 5-10, 10-20, 20-30 and 30-40 cm deep in pastures of U. brizantha Marandu (Palisade grass). The samples were analysed for pH, H+ + Al3+, soil organic matter (SOM), P, K+, Ca2+, Mg2+, exchangeable and calculated CEC, BS% and aluminium saturation. Liming and fertilisation improve the soil fertility. The highest organic matter contents were obtained for the 0-5 cm layer, with a nitrogen fertilisation of 200 kg·N·ha-1. The management practice for the pre-grazing height of 25 cm, regardless of the nitrogen, is the best strategy for soil quality and livestock production.