In the areas where irrigated rice is grown in the south of Brazil, few studies have been carried out to investigate the spatial variability structure of soil properties and to establish new forms of soil management as well as determine soil corrective and fertilizer applications. In this sense, this study had the objective of evaluating the spatial variability of chemical, physical and biological soil properties in a lowland area under irrigated rice cultivation in the conventional till system. For this […]

Sewage sludges contain high levels of organic N. If these residues are applied in excess to soils, there is the risk of polluting the groundwater with nitrate, a product of N mineralization. For this reason, one of the criteria underlying the determination of the maximum N application rate to soils is the crop available N. This paper presents the results of a 224 day laboratory leaching study on organic N mineralization of anaerobically-digested sewage sludges from two treatment plants, namely Franca […]

The management system normally affects soil nutrient availability, as a consequence of tillage practices, crop rotation and crop residues remaining in the cultivated area. The objective of this study was to evaluate the alterations in cation availability in two Oxisols in the Brazilian Cerrado under conventional and no-tillage systems for more than 10 years. The experiments were conducted in Costa Rica, state of Mato Grosso do Sul, and in Luziânia, Goiás. Both soils were Oxisols, but one being a Red Latosol […]

The use of animal manure in agricultural systems can cause water contamination and/or pollution by nutrients, especially by consecutive applications to the same area. In view thereof, the purpose of this study was to evaluate the effect of manure and fertilizer application on NH4+, NO3–, P and K leaching. For this evaluation, undisturbed soil columns were collected from a seven-year field experiment that consisted of 12 treatments, resulting from the combinations of four doses of dairy slurry with three doses […]

The objective of this study was to extract and concentrate calcium oxalate (CaOx) crystals from plant leaves that form the above mentioned crystals. The chemical and physical studies of CaOx from plant to be performed depend on an adequate amount of the crystals. The plant used in this study was croton (Codiaeum variegatum). The leaves were ground in a heavy duty blender and sieved through a 0.20 mm sieve. The suspension obtained was suspended in distilled water. The crystals were […]

The use of sewage sludge (SS) in agricultural soils is one of the most viable forms of recycling this residue. The purpose of this study was to investigate the effect of SS application on castor bean yield and nutrition in a clayey dystrophic Ultisol following a rotation of sugarcane. The treatments tested were four sewage-sludge rates (0, 5, 10, and 20 t ha-1, dry matter) calculated to supply plants with N at amounts of 0, 37.5 kg ha-1, 75 kg […]

Eucalypt is efficient at taking up Ca from the soil, however little is known about the contribution of ectomycorrhizas and organic acids to this process under field conditions. The accumulation of calcium oxalate crystals (CaOx) was evaluated in, approximately, 2,100 fine lateral roots and ectomycorrhizas of a 2.5-year-old Eucalyptus grandis x Eucalyptus urophylla hybrid, grown in a mountainous area at Viçosa, MG, Brazil. Optical and scanning electron microscopy techniques were used for CaOx observation. Abundant accumulation of calcium as druses […]

The study of the efficiency of multielement extractant solutions to assess the availability of soil nutrients for plants has increased recently. The use of these solutions increases the efficiency of soil analysis laboratories by simplifying analytical procedures. Furthermore, the determination of nutrients by Inductively Coupled Plasma Optical Emission spectrometry (ICP-OES) has increased in recent years, owing mainly to simpler test procedures and less limitations in the detection of elements. Aiming at evaluating methods of extraction and verifying their efficiency to […]

The adventitious rooting of cuttings is influenced by intrinsic and extrinsic factors of the plant material. The knowledge about the action mode of these factors upon rooting is fundamental for the successful production of clonal seedlings through minicuttings. The objective of this study was to evaluate the degree of association between the nutritional state of ministumps with the rooting of eucalypt minicuttings, grown in a clonal minigarden in tubes with subirrigation. Data from minicutting rooting and nutrient contents quantified by […]

In agricultural systems treated with sewage sludge, the management ought to seek an adequate N supply to plants, while avoiding nitrate enrichment because of its potential to pollute subsurface water bodies. Thus, when determining the maximum amounts to be applied to a specific crop, some sewage sludge and soil properties should be known. One is the fraction of organic N of the waste that will be mineralized (NMF) during the crop cycle. This quantity, combined with mineral N in the […]