Litholic soils are characterized by moderate to high erodibility and low depth. Due to these attributes, litholic soils require effective conservation practices protecting their thin top soil layer from the high erosion rates in the semiarid regions of the State of Ceará, Brazil. While the consequences of erosion on these soils are well known, the long term effects of this conservation practice on the rate of soil losses and improvement of their properties have been scarcely studied. Mass of retained […]

The effectiveness of fluid (phosphoric acid and 10-30-00 colloidal suspension) and solid (monoammonium phosphate and triple superphosphate) fertilizers was evaluated in a greenhouse experiment at the Center for Nuclear Energy in Agriculture (CENA), University of São Paulo, Piracicaba, State of São Paulo, Brazil, from June to October, 1992. Corn plants were grown in pots (8 plants per pot; 3 replicates) containing 1 kg of two red-yellow latosols with different phosphorus retention capacities, for three successive cycles (30 days each). The […]

The fumigation-extraction method was used for measuring soil microbial biomass of C (BM-C) and N (BM-N) in a red-yellow latosol under different forest types. Soil samples from eucalypt and pine plantations presented higher values of BM-C (223.72 and 207.39 mg kg-1 of C in the soil, respectively) than samples from Piptadenia rigida and regenerating secondary forest (82.94 and 79.47 mg kg-1 of C in the soil, respectively). Similar results were obtained for the litter layer. On the other hand, the […]

The objectives of this paper were: to verify the adequacy of different rainfall erosivity indices, to compare two equations to calculate the rainfall kinetic energy and to estimate the USLE K-factor (soil erodibility) of two soils (Dark – Red Latosol and Red – Yellow Podzolic soil) from the Sete Lagoas (MG) region. There was not a significant difference between the studied equations to calculate rainfall kinetic energy. The EI30 index showed to be a good rainfall erosivity predictor and can […]

Previous studies showed the effectiveness of stone barrier contours on reducing slope lengths, retaining sediment and nutrients, and decreasing runoff, erosion rate and siltation of reservoirs. The extent of these benefits regarding to soil productivity in semiarid regions, however remained unknown. The aim of this study was to determine the effects of stone barrier contours on the productivity of a lithosol thirteen years after its construction. Experiments were carried out in areas of retained sediment and in areas where the […]

This study was carried out under laboratory conditions from September to December, 1992. The objective was to evaluate the mineralization of nitrogen in cowpea (Vigna unguiculata L.) green manure, using 15N as tracer, in three major soils of Central Amazon: an Oxisol, an Ultisol and a Low-Humic Gley. The variation in amount and form of the mineral N from cowpea residues was related to the chemical characteristics of each soil. In the Oxisol and Ultisol the incorporation of green manure […]