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 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. […]

The sterilization methods are particularly important to study the influence of microorganisms on the pesticide dissipation in soils. This study, conducted in the laboratories of the Instituto Biológico of São Paulo in august 1996, tested the influence of two methods of soil sterilization – moist heat (autoclaving) and γ radiation – on the release of nonextractable or bound residues. It was studied, as example, bound residues of the herbicide atrazine in two types of soil (gley humic and dark red […]

An experiment was carried out in a greenhouse, with the surface layer of a clayey Red Yellow Latosol placed in plastic pots. A 4x3x4 factorial was used. Lime rates (0; 380; 760 and 1140 mg kg-1 of soil) and potassium rates (0; 40 and 120 mg kg-1 of soil) and alfalfa cultivars (Crioula, Moapa, Florida77 and CUF101) were studied. A randomized complete block design, with four replications, was used. Plants were harvested 70 days after sowing and allowed to regrow. […]

Nitrogen mineralization potential (No) for ten Rio Grande do Sul, Brazil, soils was studied with corn grown on 20 kg pots for 45 days, as compared with nitrogen mineralized in aerobic incubation for 32 weeks. No values ranged from 108.6 to 210.8 mg kg-1, being similar to the total nitrogen mineralized. Mineralization velocity was higher during the first four weeks, and overall mineralization rate varied from 0.2985 to 0.3181 week-1 among soils. The correlation coefficient between corn absorbed nitrogen and […]

Although periodically flooded ecosystems represent 25% of the total Amazon area, they contribute to 75% of timber production. Both periodically flooded and upland ecosystems are greatly diverse in species belonging to Leguminosae family. Some of these species are currently exploited, but the economic potential of the vast majority has been overlooked. The knowledge of the plant growth characteristics of these species under nursery conditions is the first step to understand their biology and establish artificial woodlands in deforested areas. This […]

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 […]

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 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 […]

Two methods were evaluated for scaling a set of semivariograms into a unified function for kriging estimation of field-measured properties. Scaling is performed using sample variances and sills of individual semivariograms as scale factors. Theoretical developments show that kriging weights are independent of the scaling factor which appears simply as a constant multiplying both sides of the kriging equations. The scaling techniques were applied to four sets of semivariograms representing spatial scales of 30 x 30 m to 600 x […]