The Effect of Clearing a Tropical Forest Soil

Abstract

Summary Organic matter in tropical soils under forest is delicately balanced, the continuous addition of fresh material being offset by decomposition. The forest was removed from a soil in Ghana and three degrees of exposure were tested. Chemical and physical properties were measured from 1957 to 1960. Much organic C, total N, and organic P was lost from the soil of fully exposed plots, because soil temperatures increased and fresh organic matter was no longer provided by the forest. Rate of decomposition lessened with time. Decomposition under shade, though still rapid, was significantly slower than in exposed soil. After three years’ exposure the soil produced less mineral N and had smaller cation exchange capacity, exchangeable K, and lower pH than the shaded soil. Exposure also compacted the soil, impeded drainage through the 2–6 in. layer and made the soil erode more easily.

Impacto do cultivo de citros em propriedades químicas, densidade do solo e atividade microbiana de um Podzólico Vermelho-Amarelo

“…As perdas de matéria orgânica foram, em média, de 50%, na camada de 0-20 cm, e de 30%, na camada de 20-40 cm, sendo mais acentuadas na camada de 0-20 cm, confirmando as observações de Machado et al (1981). O maior teor de matéria orgânica na área sob mata pode estar associado com a maior restituição de resíduos vegetais ao solo (Cunnigham, 1963;Godefroy & Jacquin, 1975). Em solos tropicais, a retirada da mata e a adoção de sistemas agrícolas promovem redução nos teores de As letras maiúsculas comparam as áreas sob mata e a linha da cultura, a 5% pelo teste t. As letras minúsculas comparam a mata e a entrelinha da cultura, a 5% pelo teste t.…”

Monitoring land degradation in the semiarid tropics using an inferential approach: the Kabomo basin case study, Nigeria

“…The area is shown in Figure 1. A study of this kind is particularly relevant because, despite the abundance of literature on the extent of land degradation for many areas (see, for instance, Cunningham, 1963;Seubert, et al, 1977;Aina, 1979;Adepetu, et al, 1979;Lal and Cummings, 1979;Adams and Boyle, 1982;Doormar, 1983;Kang, 1993;Lal, 1996), virtually all such studies were carried out outside the semiarid region of Nigeria where the Kabomo basin area is located. In the late 1980s, the World Bank Commissioned a study (Mortimore, 1989) to examine on a very large scale the nature and extent of soil degradation in the northernmost states (the so-called``semiarid region'') of Nigeria, but such a study appeared to be limited in scope as it did not involve empirical investigations to assess the extent of land degradation in each of the various areas that form that area.…”

Deforestation and land-use effects on soil degradation and rehabilitation in western Nigeria. I. Soil physical and hydrological properties

“…Intensive burning can also alter aggregate size distribution (Ghuman and Lal, 1989), and decrease wettability. Some of these effects of deforestation have been studied and described for Alfisols and Ultisols in west Africa (Cunningham, 1963;Nye and Greenland, 1964;La1 and Cummings, 1979;Hulugalle, et al, 1984;Lal, 1986;La1 and Ghuman, 1990;Ghuman and Lal, 1991;Ghuman, et al, 1991), soils of tropical America ( Van der Weert and Lenselink, 1972;Van der Weert, 1974;Seubert, et al, 1977a,b;Alegre, er al., 1986), and for Ultisols in Asia (Suwardjo, et al, 1985;Arya, et al, 1992).…”