The effects of sewage sludge doses on the root system of peach palm were studied in a field experiment, in randomized complete blocks, carried out in Ubatuba, state of São Paulo, Brazil. The trial was set up in July 2001, with a density of 5,000 plants ha-1. The sewage sludge doses (79.7 % water content) were 0, 38, 76, and 152 t ha-1, which were equivalent to doses of 0, 100, 200, and 400 kg ha-1 of N. The treatments were applied in the planting furrow, and […]

The evaluation of agronomic instrumentation to determine soil water content is very important for scientific research. Regardless of the technique in use, it is important that the soil water content is determined easily and quickly for the determination of the function K(q), e.g. With the objective of comparing the performance of the equipments neutron probe and TDR with a tensiometer at determining variations in the soil water content and the values of soil hydraulic conductivity obtained from the soil water […]

Field experiments involving soils require previous verification of the soil spatial variability. The objective of this research was to study the spatial variability of soil physical properties of an experimental plot using geostatistics. The experiment was conducted in 1982 at the Experimental Center of the Instituto Agronômico in Campinas, state of São Paulo, Brazil, on a Red Latosol (Rhodic Ustox) under conventional tillage in a 30 x 30 m area, with sampling points arranged in a 5 m square grid. The analyzed properties were […]

The mechanical penetration resistance of a soil strongly influences plant development since the root growth as well as the crop yield change inversely proportional to its value. The bean grain yield (GY) and the penetration resistance (PR) in a Dystrophic Red Latosol (Rhodic Ustox) located at the Experimental Station of the Faculdade de Engenharia/UNESP in Ilha Solteira county, São Paulo State, Brazil (22 º 23 ‘ latitude S; 51 º 27 ‘ longitude W), were analyzed in the crop year 2001/2002. The main objective was to work out […]

This study reports on the use of GIS (Geographical Information System) tools for identifying and mapping landform units and soilscapes in a case study of a watershed in the region of Viçosa, Minas Gerais state, based on a topographical base map at a 1:50000 scale. Field work was undertaken to estimate the degree of accuracy of landform units / soilscape identification, obtaining an agreement of 72 % between the automatic and field work classification, and to correlate obtained soilscapes with dominant soil […]

Nutrient losses are influenced by the soil tillage system. In general, nutrient concentrations in runoff are higher in soil conservation tillage systems, whereas the total nutrient losses are higher in conventional soil tillage. The NH4+ and NO3– losses in water and mineral nitrogen in runoff sediment were determined under natural rainfall in the following tillage systems: six years of no-tillage (NT6), nine years of no-tillage (NT9), nine years of chisel plow plus disking cultivation (CD9), nine years of plowing plus […]

The influence of two species of arbuscular mycorrhizal fungi (AMF) on the ATPase and pyrophosphatase activities of corn root microsomes was investigated at 20, 30, 40, and 60 days after planting. The microsomes were isolated by cell fractionation from corn roots colonized with Glomus clarum or Gigaspora margarita. Both fungi led to a significant increase in the ATPase and pyrophosphatase activities though the highest activities were observed in roots colonized with G. clarum. Kinetics analysis suggested that mycorrhizal colonization promoted a […]

According to their hydrophobicity degree, organic substances can increase the aggregate stability, reducing the rate of water infiltration into the aggregates. Our study investigated the aggregate genesis and stabilization in a Red-Yellow Latosol under organic compound addition with distinct hydrophobic and hydrophilic characteristics. Air-dried samples from the A and B horizons were incubated with different doses of three organic compounds: estearic acid, amid and humic acid purified in accordance to the International Humic Substances Society. The experiment was organized with […]

Brazilian literature lacks data on soil and water loss by water erosion in perennial crops although such data would be essential for conservation planning and erosion modeling studies. Data of soil and water loss under natural rainfall (July 1960 to June 1972) in Pindorama, State of São Paulo, Brazil, were used to calculate the soil loss ratio (SLR) and C factor for the Universal Soil Loss Equation (USLE) in coffee (Coffea arabica L.) planted in five spacings (3.0 x 0.5 m, 3.0 x 1.0 m, 3.0 x 2.0 m, […]

The behavior of glyphosate in a Rhodic Oxisol, collected from fields under no-till and conventional management systems in Ponta Grossa, Parana state (Brazil) was investigated. Both agricultural systems had been in production for 23 years. Glyphosate mineralization, soil-bound forms, sorption and desorption kinetics, sorption/desorption batch experiments, and soil glyphosate phythoavailability (to Panicum maximum) were determined. The mineralization experiment was set up in a completely randomized design with a 2 x 2 factorial scheme (two management systems and two 14C radiolabelled positions in the […]