Volume 30, Number 3, 2006

Soil temperature is a property that directly affects crop growth and is influenced by the energy balance on the soil surface. Thus, soil management systems influence soil temperature because they change soil surface conditions. The objective of this study was to determine the effect of three soil management systems on soil temperature throughout the snapbean cycle. A field experiment was arranged in a randomized block (split plot) design with four replicates, on a soil classified as Hapludalf. The treatments were […]

The aim of this study was to characterize the morphological, physical and hydraulic soil properties in a toposequence under native plant cover in a permanent observation plot of 320 x 320 m installed in the Assis Ecological Station, São Paulo State, Brazil. The plot is covered by a remnant Savanna Woodland (Cerradão) vegetation of the southern border zone of the great Cerrado domain. The bi-dimensional geometry (horizontal and vertical) of the soil horizons in a toposequence provided details on the […]

Revegetation with tree species is an appropriate strategy for the rehabilitation of degraded areas. However, the establishment and growth of these species in low nutrient soils depends upon several factors, such as the ability of the species to form and benefit from mycorrhizae. In this study, conducted in pots under greenhouse conditions at the Federal University of Lavras in Minas Gerais, Brazil, aspects of host-fungus relationship in tree species found in Southeastern Brazil were evaluated. The following arbuscular mycorrhiza (AM) […]

Applying lime on the soil surface in soils managed under no-tillage has caused an excess of basic cations in the most superficial layers of the soil profile. On the other hand, subsoil acidity is considered a constraint to the development of deep plant roots. The objective of this study was to evaluate Ca2+, Mg2+, NO3– and SO42- leaching in the soil profile as affected by liming and top dressing nitrogen fertilization in cotton, grown with straw cover on the soil […]

In no-tillage systems lime is applied on the soil surface to avoid soil mobilization. Nitrogen fertilization adds anions that can increase the solubility of basic cations of the soil due to formation of ionic pairs. The objective of this study was to characterize the dynamics of anions (SO42- and NO3–) and cations (NH4+, Ca2+, Mg2+ and K+) in the soil solution, and the nutrient uptake by cotton plants subjected to different lime application forms and ammonium sulfate fertilization, with straw […]

Conilon coffee (Coffea canephora) is very important for the economy of the state of Espírito Santo and its organic cultivation is increasing. However, there is a lack of information on leaf reference values for this form of management, as well as a nutritional diagnosis. The objective of this study was to establish and compare reference patterns and to propose adequate values of leaf nutrient concentrations obtained on high yielding conilon coffee plantations, cultivated under organic or conventional systems, in the […]

The efficient use of phosphate fertilizers in soils of the tropical region is still a challenge, mainly regarding long-term soil management. Based on the cumulative response of three successive maize cultivations, alternatives of phosphorus supply combining P sources and application methods were compared in a formerly fertilized Red Argisol. Treatments arranged in a 4 x 3 + 1 factorial scheme represented by four P sources (180 kg ha-1 P2O5) as triple superphosphate – TS, magnesium termophosphate – MT, Arad reactive rock phosphate – RP, and Araxá […]

The concentration of orthophosphate ions released from Fe-K-P compounds (Fe3KH8(PO4)6 .6H2O and Fe3KH14(PO4)8 .4H2O) present in superphosphates increases with pH, which initially suggests that the agronomic effectiveness of P fertilizers containing high amounts of these compounds would also increase with soil pH but studies considering activity, instead of concentration, are necessary. With this purpose, both compounds were synthesized under laboratory conditions, characterized by elemental chemical analysis, optical microscopy, X ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and […]

Lime recommendations developed for conventional systems are being used in no-tillage systems with different dynamics of the acidity attributes, due to organic matter and nutrient accumulation on the superficial layer and lower aluminum toxicity. This study associated different acidity indicators of a Rhodic Hapludox after eight years under no-tillage system with soybean plant characteristics in order to establish liming criteria. Two field experiments were compared, both under no-tillage for eight years; one had previously been under conventional tillage and the […]

The objective of this study was to identify site-specific management zones by means of chemical soil fertility indicators on sugarcane-cultivated Latosols (Oxisols), using indicator kriging, aiming an optimized use of precision agriculture techniques. The study was conducted in a 90 ha section of a larger field (1.900 ha) near Jaboticabal, São Paulo State – Brazil (21 ° 15 ‘ S and 48 ° 18 ‘ W). A 50 m regular grid was drawn on the experimental area (300 by 3.000 m). Soil samples were obtained at each 50 m grid point (420 points) from […]