F. Lombardi Neto

Parâmetros erosividade da chuva e da enxurrada correlacionados com as perdas de solo de um solo Bruno Não-Cálcico Vértico em Sumé (PB)

Simple linear correlations among runoff and rainfall erosivity parameters and soil losses caused by erosivity rainfall in Haplargids were studied. Data related to 1986-1990 were obtained in the Experimental Station at Sume-Brazil. The rainfall erosivity parameters were the following: a) total height of the rainfall (P) in mm; b) maximum intensity (In): I5; I10; I15; I20; I25; I30; I35; I40; I45; I50; I55; I60 and I120 minutes in mm h-1, respectively; c) total kinetic energy by the Wischmeier & Smiths and by the Wagner & Massambanis methods in MJ ha-1 (KE and KEW); d) kinetic energy of intensities higher than 10 mm h-1 (KE > 10 and KEW > 10) in MJ ha-1; e) kinetic energy of intensities higher than 25 mm h-1 (KE > 25 e KEW > 25) in MJ ha-1; f) total kinetic energy products by maximum intensities rainfall (EIn): EI5, EI10; EI15; EI20; EI25; EI30 EIW30; EI35; EI40; EI45; EI50; EI55; EI60 and EI120 in MJ mm ha-1h-1, respectively; g) total height of rainfall products by maximum intensity rainfall (PIn): PI5, PI10, PI15; PI20; PI25; PI30; PI35; PI40; PI45; PI50; PI55; PI60 and PI120 in mm2 h-1, respectively; and h) runoff volume (Vu) in m3. The runoff erosivity parameter (Vu) best estimated (r = 0.812) the soil losses in Sume-PB. Among rainfall erosivity parameters, the PI25 type (r = 0.753) was best correlated with soil losses. The Wischmeier & Smiths and the Wagner & Massambanis equations used to calculate the total kinetic energy rainfall presented the same degree of precision in estimating soil losses.

CAP_USO: uma ferramenta para auxiliar o planejamento do uso da terra

A classificacao da capacidade de uso das terras e uma tarefa complexa, dificil e demorada, que envolve conhecimentos interdisciplinares e uma vasta quantidade de dados. O objetivo deste trabalho foi desenvolver uma ferramenta (CAP_USO), utilizando a tecnica de sistemas especialistas, para determinar a capacidade de uso da terra, com base em conhecimento adquirido de literatura e de entrevistas com especialistas desta area. Foram considerados doze fatores limitantes ao uso da terra, e a capacidade de uso foi determinada tambem por sete especialistas. Os resultados da validacao mostraram que o CAP_USO foi mais rigoroso que os especialistas ao determinar as classes de capacidade de uso, e a concordância entre os resultados diminuiu com o aumento da declividade. As discordâncias verificadas entre os especialistas e o sistema pouco influem na classe de capacidade de uso, pois o CAP_USO e um sistema aberto que permite ajustes, alteracoes e modificacoes conforme as condicoes locais. A tecnica mostrou-se eficaz, permitindo determinar, com rapidez, a capacidade de uso da terra, contribuindo para dar mais agilidade ao processo de tomada de decisao para o planejamento do uso da terra.

Parâmetros erosividade da chuva, da enxurrada e da chuva-enxurrada correlacionados com as perdas de solo de um luvissolo

Simple linear, multiple linear and nonlinear correlations between rainfall, runoff and rainfall-runoff erosivity parameters were studied, as well as soil losses caused by erosive rainfall on a Haplargids. Data were obtained in the period from 1986 to 1990 at the Experimental Station in Sume, which belongs to the Universidade Federal da Paraiba - UFPB, Paraiba State, Brazil. Individual rainfalls registered in 136 rain gauges were analyzed for the determination of rainfall, runoff and rainfall-runoff erosivity parameters. The runoff volume, single or combined with rainfall characteristics improved the estimated soil losses of individual rainfall significantly. The erosivity parameters for rainfall-runoff a(Vu α I30)b; a(Vu α I5)b; a(EIA)b and runoff a(Vu)b were best fit to estimate soil losses caused by individual storms. The rainfall erosivity parameters that included the product of rainfall volume at a maximum intensity for thirty minutes (VrI30) were the ones that correlated best with soil losses.

CRESCIMENTO AÉREO E RADICULAR DA SOJA EM SOLOS COMPACTADOS E INOCULADOS COM ESTIRPES DE Bradyrhizobium japonicum

A soybean crop experiment using samples from a sandy Dark Red Latosol was conducted in a greenhouse at the Universidade Federal de Uberlândia, Minas Gerais, Brazil from July/1996 to February/1997, to evaluate the effects of inoculation and subsoil compaction on the shoot dry matter production (ADMP), root dry matter production in the superior ring of the column, and nitrogen absorption and concentration in soybean shoots.. The treatments were set in a 2 x 3 x 4 factorial design and corresponded to sterilized and non sterilized soil (using 250 cm3 m-3 methyl bromide), three strains of Bradyrhizobium japonicum soil native, SEMIA 5079 and SEMIA 5080 inoculated in seed soybean and four levels of compaction (bulk densities of 1.15, 1.30, 1.45 and 1.60 kg dm-3) applied with a hydraulic press on the soil placed in a central ring of a column made by three 15 cm diameter PVC rings. Forty-seven days after germination, the plants were harvested, dried and weighed. The roots of the superior ring were harvested and measured. The ADMP of soybean increased in the sterilized soil and inoculation with strain SEMIA 5080 at densities 1.15 and 1.30 kg dm-3. For higher densities, the strains studied did not have any effect. The compaction caused linear reductions-either in nitrogen concentration and in shoot dry matter production of the non sterilized soil, - and parabolic reduction, with the highest production at 1.35 kg dm-3 density in the sterilized soil. Nitrogen concentration in the shoots was lower with inoculation of the strain SEMIA 5079 in sterilized soil, with no difference among treatments in non-sterilized soil. A greater root production in the surface layer (ring) occurred in non-sterilized soil with seeds inoculated with Bradyrhizobium japonicum. In sterilized soil, the greatest production occurred due to inoculation of the strain SEMIA 5079. Compaction caused an increasing linear effect in root growth in non-sterilized soil and parabolic, with greatest growth at 1.45 kg dm-3 density in sterilized soil.