In this study available cooper (Cu) content in different sources of this micronutrient was determined using several extractants. The cooper sources were: coppper oxide p.a. + copper powder p.a., copper oxide 40 Ind., CuSO4.5H2O p.a., chalcopyrite ore, copper powder p.a. and copper oxide p.a., and they were used in the following extraction procedures: total Cu content and soluble Cu contents in water, citric acid at 20 g L-1, neutral ammonium citrate (1 + 9) and DTPA at 0.005 mol L-1. […]

Knowledge on mineral nutrient dynamics in coffee trees is important to identify the period of greatest nutritional requirement by the plant, allowing the improvement of fertilization techniques. The aim of our research was to study Ca and Mg dynamics in coffee fruits from anthesis to maturation and compare it with the dynamics of the same elements in leaves of productive branch leaves. The experiment was carried out with three Arabic coffee varieties (Catuaí Vermelho IAC-99, Rubi MG-1192 and Acaiá IAC-474-19) […]

The objective of this paper is to study selected components of the nutrient cycle of pure and mixed stands of native forest species of Atlantic Forest in southeastern Brazil. Tree diameter, height, above-ground biomass, and nutrient content were determined in 22-year-old stands. Litterfall, litter decomposition, and nutrient concentration were evaluated from August 1994 to July 1995. The following species were studied: Peltogyne angustiflora, Centrolobium robustum, Arapatiella psilophylla, Sclerolobium chrysophyllum, Cordia trichotoma, Macrolobium latifolium. The litter of a natural forest and […]

The soil particle-size distribution has great influence on the plant yield. In the 2002/2003 growing season, plant and soil attributes of an experimental station of the Faculdade de Engenharia/UNESP (Ilha Solteira/SP – Brazil) were analyzed: common bean grain yield (GP), straw yield (SP), clay content (CL), silt (SI) and sand (SA) of a Red Latosol (Oxisol) under no-tillage. The objective was to analyze the variability of the evaluated attributes to characterize spatial dependences and to study linear and spatial correlations […]

Brazil is the most important exporter of cashew nut in the world. The production is concentrated in the northeast region, which accounts for 97 % of the national production. However, in the recent years the cashew nut production has been declining, specially in the state of Ceará, mainly due to inadequate soil management. The aim of this study was to evaluate alterations in the physical and chemical properties of an Ultisol submitted to distinct soil management practices and the development […]

The effect of grazing pressure in sheep production has been studied, but not in relation to soil microbiological parameters or the consequences on soil fertility. The effect of grazing pressure (GP) by sheep on biomass and microbial activity related to C and N compounds cycling in subtropical region soil was studied. Soil samples were collected from the 0-10 cm and 10-20 cm layers in pastures with low GP (5 animals ha-1), high GP (40-50 animals ha-1) and in absence of […]

Sediments carried away by the muddy waters of the Guamá River and the heterogeneity of these substances are responsible for the soil formation and diversity of chemical characteristics in the periodically flooded areas. This study aimed at determining the physical and chemical attributes of a low floodplain (varzea) soil of the Guamá river, in different periods, cultivated with Paramaribo canarana (Echinochloa polystachya H.B.K) or canarana erecta lisa (Echinochloa pyramidales Lam). The experimental design was entirely randomized, in a 4 x […]

An experiment was carried out at the Bebedouro Experimental Station in Petrolina, state of Pernambuco, from January 1999 to December 2001, on a sandy Yellow Eutrophic Argisol, with the objective of evaluating the effect of green fertilizers associated with liming and mineral and organic fertilization on the soil chemical attributes and the yield and quality of irrigated melon (Cucumis melo). A randomized complete block design with split-plots and four replications was used. The treatments assigned to the main plots were […]

The time-domain reflectometry (TDR) technique has been one of the most used techniques to determine soil volumetric water content (q) owing to some favorable characteristics such as high precision, non-ionizing radiation and little influence of soil salinity, bulk density and texture. However, most of the TDR equipment and probes available do not allow a detailed measurement along the soil profile, as for instance the neutron probe does. For conventional TDR probes holes or trenches must be opened in the soil […]

The current sugarcane management techniques employed involve vigorous soil revolvement with ploughs, heavy disks and subsoilers before planting. The aim of this study was to evaluate the degree of modification of some physical properties of a kaolinitic Oxisol (LVd) and a kaolinitic – oxidic Oxisol (LVdf) under sugarcane and native forest in Jaboticabal county, São Paulo state, Brazil. The experimental design was completely randomized, in a 4 x 3 split plot scheme (four managements and three depths), with four replications. […]