ABSTRACT Studies on lability of soil phosphorus (P) under integrated crop-livestock systems (ICLS) are still scarce, especially for deep soil layers (more than 0.20 m depth) and different managements in the crop and livestock phase. Distinct management in these phases may lead to a different distribution of soil P pools according to its lability (labile, moderately labile, less labile and residual) and, consequently, the P availability for plant nutrition. This study aimed to determine the soil P pools, by P […]

Organic matter plays an important role in many soil properties, and for that reason it is necessary to identify management systems which maintain or increase its concentrations. The aim of the present study was to determine the quality and quantity of organic C in different compartments of the soil fraction in different Amazonian ecosystems. The soil organic matter (FSOM) was fractionated and soil C stocks were estimated in primary forest (PF), pasture (P), secondary succession (SS) and an agroforestry system […]

Land application represents an efficient alternative for disposal of biosolids. However, depending on the origin (urban and/or domestic) and the treatment system, biosolids may contain high amounts of heavy metals, which can gradually build up in the soil. Soil chemical amendments in contaminated areas can reduce the bioavailability and mobility of heavy metals and, consequently, minimize the risks of their adverse effects on the environment. The objective of this study was to evaluate the effects of four chemical amendments [calcium […]

The addition of fertilizers to the soil increases P contents in many forms of different bond energies with soil colloids. This has been observed in the soil surface layer under no tillage system, however there is little information about the availability of these P forms to plants. The study aimed to evaluate the bioavailability of P forms of a soil under no tillage with P applications. Samples were collected (0-10 cm) in a Rhodic Hapludox that had been fertilized with […]

Benchmark soils are a collection of soil orders that represents a particular geographical region. Knowledge on their properties and behavior may be applied to solve management problems of other soils with similar properties. The present study was carried out to determine the Mn and Fe available concentration by different extractants and their distribution among soil fractions in benchmark soils of Pernambuco State, Brazil. It was also aimed at studying the relationship between routine extractants and micronutrient forms in the soils. […]

One of the best options for final disposal of sewage sludge is its use for agricultural purposes. Excessive heavy metal concentrations in sludge, however, pose a risk to the environment. It is therefore important to determine not only the availability, but also the distribution of such metals in different soil fractions as a result of sludge application. Our study aimed at evaluating both the redistribution of Zn among soil fractions and the Zn-DTPA available concentration in sludge-incubated soils. Samples of […]

To evaluate a fractionation scheme for Zn in a sandy soil (Ultisol) and its relation with Zn availability for Cynodon spp cv. Tifton-85, an experiment was carried out in greenhouse, with a factorial scheme (5 doses of zinc, 2 doses of lime and 2 times of sampling), in a completely randomized block design, with three replications. The doses of Zn were: 0; 2.5; 5.0; 7.5 and 10 mg dm-3; half of the pots did not received liming (V = 42%) and, in the other half, liming was […]

Different soil boron fractions were evaluated from 29 superficial (0-20 cm) soil samples in Ceará, Brazil. Relationships were established between soil fractions and soil properties and soluble boron, which has been used as an index of boron availability to the plants. Fractional boron analyses of the soils were carried out following a sequential procedure. The following determinations were carried out: the water soluble boron (B-Sol), the not specifically adsorbed boron (B-NEsAd), the boron associated to manganese oxide (B-OxMn), the boron […]