Volume 21, Number 4, 1997

Estimates of deforestation in the Brazilian Amazon, primarily for shifting cultivation and pastures, exceed the land area for the State of Rondônia. An experiment was conducted on a Xanthic Hapludox near Manaus, Brazil to establish soil nutrient depletion patterns and fertilizer and lime requirements for continuous cultivation after slash-and-burn clearing. Yield responses to N, P, K, Mg, S, B, Cu, Mn, Zn and lime were evaluated during eight years of cultivation. Seventeen crops were grown during the period from 1981 […]

Phosphorus availability in samples of Aquatibia (Typic xerofluvent) and Hoda (Ultic haploxeralf) soils incubated with increasing amounts of organic materials (barley straw, cowpea plant tops, dairy manure and sewage sludge) was estimated by different chemical methods and by measuring the activity of the enzymes acid phosphatase and phosphodiesterase, at the Department of Soils and Environmental Sciences of the University of California/Riverside, from January to November of 1985. In a greenhouse study, yield of dry matter and P uptake by corn […]

The nutrient cycling of two types of vegetation, (a “low forest” – 15 m of height, and a “short forest” – 25 m of height), characteristic of the sandy belts on the Coastal Plains of Ilha do Mel was studied, from June 14th, 1991 to June 12th, 1993. In this first step the soil’s chemical and physical characteristics were studied, in relation to the physical environment and the parent material. The soils were classified as allic/dystrophic podzols, where the B […]

The precise sampling of soil, biological or micro climatic attributes in tropical forests, which are characterized by a high diversity of species and complex spatial variability, is a difficult task. We found few basic studies to guide sampling procedures. The objective of this study was to define a sampling strategy and data analysis for some parameters frequently used in nutrient cycling studies, i. e., litter amount, total nutrient amounts in litter and its composition (Ca, Mg, Κ, Ν and P), […]

The objective of this work was to quantify the main forms of P derived from fertilizer in soils of varying physical and chemical properties, cultivated with sugar-cane, in Pernambuco. Soils from 11 commercial plantations were sampled following the harvest of the plant-cane (Jan. 1994), that had been fertilized in the furrow 18 months before. To find samples with fertilizer-derived P, a pit was opened perpendicular to the plant line and 28 soil samples were taken with the aid of a […]

The mass balance of weathering of soils derived from basic-ultrabasic rocks under the subtropical climate of southern Brazil, the least weathered soils found to date in the Rio Grande do Sul state, showed a higher relative concentration of the mobile elements in the surface horizons than in the subsurface horizons. These features, associated to the soil mineralogy and morphology, indicate the occurrence of erosive-depositional events in a pedogenetically recent past as well as a main contribution from less weathered materials […]

The purpose of present study was to evaluate the use of filter cake and stillage as amendment for reclamation of a saline-sodic soil. The experiment was conducted in greenhouse during July – October, 1993, utilizing an eutrophic alluvial sandy loam soil of Irrigated Perimeter of São Gonçalo-PB and adopting a 22 x 2 factorial in a randomized block design with four replications. The treatments consisted of presence/absence or combination of gypsum and filter cake and leaching with rainwater or stillage. […]

Soil and water losses were evaluated from 1987 to 1995, on a very clayey red dusky latosol, with 0.03 m m-1 slope, of Embrapa-Centro de Pesquisa Agropecuária do Oeste, at Dourados, Mato Grosso do Sul State, Brazil. Soil tillage systems used for growing wheat and soybean in succession were: chisel plow + tandem disk (ES), offset disk + tandem disk (GP), no tillage (PD) and conventional tillage, with no vegetable cover (DE). All tillage operations and seeding were in the […]

The effects of continuous sugarcane cropping on the physical and morphological properties of a clayey xanthic ferralsol were studied in the region of the Low Coastal Tablelands of Alagoas State, Brazil. Four sites were selected at Caeté mill, São Miguel dos Campos, State of Alagoas, Brazil, involving a native forest (Tn), and sugarcane fields, cultivated for periods of two (T2), eighteen (T18) and twenty-five (T25) years. The soils were morphologically characterized, and samples were taken from each horizon to determine […]

The effect of sewage sludge pelletization added at rates of 0, 1 and 5% (v/v) of dry material was studied on corn growth and absorption of Zn, Cu and Ni, with or without the addition of CaCO3 to increase soil pH to 6.0. Three Hapludox soil samples from the State of São Paulo, Brazil, “latossolo roxo”, “latossolo vermelho-escuro” e “latossolo vermelho-amarelo” (LR , LE and LV, respectively) were used in a greenhouse experiment conducted in Campinas, State of São Paulo, […]