Knowledge on rainfall erosivity (R) of particular sites is fundamental for soil loss estimation by the Universal Soil Loss Equation (USLE) and therefore highly important in conservation planning. In order to obtain the R value estimates for places where it is unknown, an artificial neural network (ANN) was developed for the state of São Paulo, and its accuracy compared with the Inverse Distance Weighted (IDW) interpolation method. The developed ANN presented a smaller mean relative error in the R estimation […]

Appropriate boron (B) availability in soils favors root growth, and a sufficient supply of this micronutrient is very important for adequate rice development and yield in upland fields, depending on the cultivars and soil type. This study aimed at evaluating the influence of B addition on growth of roots and shoot of three upland rice cultivars. The experiment was carried out in a greenhouse, in 10 L pots containing 8 kg of an Hapludox; the experiment was in a completely […]

The study of the spatial variability of soil attributes can help in the determination of a specific management strategy that enhances agricultural productivity. The present study aimed at the evaluation of a possible influence of the soil management on spatial variability of a Dystroferric Red Latosol (Oxisol) physical properties. The study was carried out in 2002, in three adjacent areas, in Lavras, Minas Gerais state, Brazil, with the following management systems: A1 – fallowing for three years; A2 – recently […]

The majority of N from mineral fertilizers and cover crops is usually not used by the very next corn crop, but can be absorbed by follow-up crops. The objective of this study was to evaluate the use of residual nitrogen from urea, sunnhemp (Crotalaria juncea) and millet (Pennisetum americanum) labeled with 15N, applied to no-tillage corn in the previous growing season, in a Red Latosol of the Cerrado. The study was conducted in an experimental farm of the Sao Paulo […]

Organic agriculture is an emerging activity in the upper mid São Francisco River Valley, requiring technologies that are in line with the principles of this agricultural system. A study was carried out at Embrapa Semi-Árido to evaluate the efficacy of natural phosphates applied to three regional soils (dystrophic Grey Argisol – PAGd, eutrophic Yellow Argisol – PAe and Vertisol – V) planted with melon (Cucumis melo) in pots accommodated on wooden benches. The factorial treatments (3 x 4) + 1 […]

The Ca/Al ratio is determinant for root deepening in the soil subsurface layer. Liming this layer can improve root growth and nutrient absorption. Thus, a greenhouse trial was carried out using soil columns. Two varieties of coffee plants (Catuaí and Icatú), one Al-sensitive and the other Al-tolerant, respectively, were evaluated in limed and surface-fertilized soil, whereas 0.0; 0.49; 1.7; 2.9; 4.1; 6.6 and 9.3 t ha-1 of limestone were applied to the subsurface soil. Plants were cultivated for 6.5 months […]

In precision agriculture management principles must be adapted to the field variability. This requires efficient techniques to estimate and map the spatial and/or temporary variability of soil attributes and properties. However, the determination of some variables that characterize the properties of a particular soil is often onerous and troublesome. In these situations it is interesting to estimate such variables as a function of others that present good space correlation with the forner and are of simpler determination. This is possible […]

Brazilian soils, especially in the Cerrado region, are highly weathered and poor in some cationic micronutrients in the soil solution. Diffusion is the main transport mechanism to the root surface. The adoption of management practices such as the use of green manures might favor the diffusive flux (DF) and availability of micronutrients to plants. The present experiment aimed to evaluate the effect of incorporation of two distinct green manures into a clayey Red Latosol (LV, Typic Haplustox) on the DF […]

In no-tillage systems, crop residues and nutrients, namely phosphorus and calcium, accumulate in soil surface and can inactivate soil aluminum. In this way, only the presence of this element in soil analysis does not indicate plant toxicity, since organic and inorganic anions may affect the free aluminum dynamics by decreasing its activity in the soil solution. Knowledge on ion activity and speciation in soil solution is therefore useful to understand Al dynamics. Ionic activity and speciation were determined in the […]

A population consists of individuals and a correct sampling of the individuals estimates population characteristics adequately. However, to evaluate soil fertility, what would be the soil individual (sample units), and of what size? The objective of this study was to determine the dimension of the individual soil component of a particular population, in three sampling areas: under no-till or under conventional tillage before or after plowing, and to evaluate soil fertility and develop a soil sampling method, determining the number […]