Qualidade do solo de uma microbacia do Rio Una (Aliança) - BA sob diferentes usos da terra

A retirada da vegetação natural para implantação de sistema agrícola provoca um desequilíbrio no solo, se o processo de adição da matéria orgânica for inferior ao de decomposição, este sistema não atinge novamente seu equilíbrio, provocando a degradação do solo. O presente estudo teve como objetivo avaliar mudanças nas características químicas e físicas e no teor de carbono orgânico total de um solo submetido a diferentes sistemas de uso. 1 - remanescente de Mata Atlântica, 2 - cacau (Theobroma cacao), e 3 - pastagem (Brachiaria decumbens). Para cada uso foram coletadas amostras nas profundidades de 0 - 10 e 10 - 20 cm. Procederam-se às análises químicas e físicas e determinação de carbono orgânico total, nitrogênio e fósforo no solo. A substituição da vegetação natural pelos sistemas cacau e pastagem ocasionaram mudanças no teor de argila na camada de 0 – 10 cm e nos teores de argila e silte na segunda camada 10 – 20 cm. Para as características químicas avaliadas (0-10 cm) observou-se maiores teores de Ca+2, Mg+2 e P no sistema cacau, enquanto a pastagem apresentou maior pH e teores de K+ e menor CTC. Os atributos Al+3 e m decresceram e V aumentou para os dois usos do solo.Na segunda camada 10 – 20 cm os sistemas cacau e pastagem apresentaram mudanças apenas em relação ao teor de Ca+2, e para o sistema cacau maior teor de P. Os diferentes sistemas de uso do solo não ocasionaram mudanças no teor de COT e N do solo. Na primeira camada foram encontradas boas correlações entre características físicas e COT para mata. O COT e atributos químicos na segunda camada apresentaram correlações significativas apenas para a área sob pastejoThe withdrawal of the natural vegetation in order to implement an agriculturist system provokes a disequilibrium in the ground; if the process of adding organic substances is inferior to the decomposition process, this system won’t be able to reach its balance again, provoking the ground degradation. This study had as objective evaluate changes in the chemical and physical characteristics of the ground and in the total organic carbon level of a ground that has experienced different systems of use: 1 - remainder of Mata Atlântica, 2 - cacao (Theobroma cacao), and 3- pasture (Brachiaria decumbens). For each use, samples were collected, in the depths of 0 - 10 and 10 - 20 cm. The chemical and physical analyses had been proceeded, and the determination of the total organic carbon, nitrogen and match in the ground. The substitution of the natural vegetation for the cacao and pasture systems caused changes in the level of clay in the layer of 0 – 10 cm and in the levels of clay and silte in the second layer 10 – 20 cm. To the chemical characteristics evaluated (0-10 cm), it was observed that the levels of Ca+2, Mg+2 and P were higher, and in the cacao system, while the pasture showed higher pH andlevels of K+ and lower CTC. The attributes Al+3 and m decreased and V increased for the two uses of the ground. In the second layer 10-20 cm the cacao and pasture systems showed changes just related to the level of Ca+2, and for the cacao system, higher P level. The different systems of ground use didn’t cause changes in the level of TOC and N of the ground. In the first layer, it was possible to find good correlations between physical characteristics and bush TOC. The TOC and chemical attributes inthe second layer showed significant correlations just for the pasture areaConselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNP

EFEITO DA COMPACTAÇÃO EM DOIS SOLOS DE CLASSES TEXTURAIS DIFERENTES NA CULTURA DO RABANETE

The decrease in pore that are submitted to the certain pressure, causes an increase soil bulk density, causing the compactação process, affecting the ideal development of crop root system. Consequently the present study has as obejective to evaluate the effects of different compaction levels in two soils with differrent textural classes on the yilol of aerial biomass and root of radish. The experiment was carried out in a green house at the, UFRPE, where two samples of soils from 0-20 cm with the following textural classes: sand clay loan (NITOSSOLO) compacted to bulk densities of 1,05; 1,26 and 1,47 g cm-3 and sandy (PLANOSSOLO) compacted to densities of 1,54; 1,76 and 1,98 g cm-3. A severe reduction was observed in the production of bulbs a function of the levels compaction where in the sand clay loan texture there was no development of the bulbs in the density of 1,47 g cm-3, differing from at observed in the sandy texture soil, where the largest density (1,98 g cm-3), showed development of the bulbs. The compaction in subsurface alters the distribution of the root system of he crop along the profile of the soils, without decrease in the production of roots

CARACTERÍSTICAS QUÍMICAS E FÍSICAS DE UM SOLO SOB FLORESTA, SISTEMA AGROFLORESTAL E PASTAGEM NO SUL DA BAHIA

The withdrawal of the natural vegetation in order to implement an agriculturist system provokes disequilibrium in the soil. This study had as objective: evaluate changes in the chemical and physical characteristics of the ground and in the total organic carbon level of a ground that has experienced different systems of use: remainder of Atlantic Bush, cacao (Theobroma cacao), and pasture (Brachiaria decumbens). For each use, samples were collected, in the depths of 0 - 10 and 10 - 20 cm. The chemical and physical analyses had been proceeded, and the determination of the total organic carbon, nitrogen and match in the soil. The substitution of the natural vegetation for the cacao and pasture systems caused changes in the level of clay in the layer of 0 ¿ 10 cm and in the levels of clay and silte in the second layer 10 - 20 cm. To the chemical characteristics evaluated (0-10 cm), it was observed that the levels of Ca+2, Mg+2 and P were higher, and in the cacao system, while the pasture showed higher pH and levels of K+ and lower CTC. The attributes Al+3 and m decreased and V increased. 10-20cm the cacao and pasture systems showed changes just related to the level of Ca+2, and for the cacao system,higher P level. The TOC and chemical attributes in the second layer showed significant correlations just for the pasture area