Hydro-physical properties of an Oxisol under different management systems
01/Dec/2007
Chiseling is one of the mechanical practices that can be used in no-tillage (NT) soils in order to reduce soil bulk density, resistance to root penetration, and to increase water permeability. The effect of these changes on plant growth and consequently on grain yield depends on climatic conditions. In soils with ideal moisture conditions, the physical limitations tend to be less noticeable. This study aimed to analyze the changes in the physical and hydric properties of a chiseled Oxisol under […]
Soil physical attributes in integrated cattle raising-crop production system under no-tillage
01/Oct/2007
Soil compaction is one of the most important reasons for decrease in crop yield. The impact of animal trampling on integrated beef cattle raising-crop production systems were studied to evaluate the changes in soil physical properties (bulk density, porosity, soil resistance to penetration and soil water infiltration). The field experiment was carried out in Jari, in the mid- plateau region of Rio Grande do Sul State, Brazil. Three management systems of winter pastures (black oat; Avena strigosa Schreber + ryegrass; […]
Sampling for soil fertility evaluation as influenced by sampling tool and soil tillage
01/Oct/2007
The measures of the average and variability of soil fertility indexes can vary with the sampling tool and soil tillage type. Soil sampling methods must be developed that are more reliable to represent the real conditions of soil fertility. This study aimed at an evaluation of the effects of the cutting shovel and hand auger on measures of average and variability of the soil fertility index (a) under no-tillage (NT) and conventional tillage (CT), (b) to estimate the minimum number […]
Soybean grain yield and least limiting water range in an oxisol under chiseled no-tillage
01/Apr/2007
The least limiting water range (LLWR) was used to determine several factors that influence plant growth. The LLWR is defined as the water content range in which aeration (AFP) and soil resistance to root penetration (RP) are not restrictive, within the field capacity (FC) and permanent wilting point (PWP). The aim of the present study was to determine the LLWR and soybean grain yield in an Oxisol under non-tillage (NT) and chiseled no-tillage (CNT) systems. The soil density, LLWR, soil […]
Water-soluble cations in shoots of annual crops as affected by lime and phosphogypsum surface application
01/Feb/2007
Surface liming efficiency can be increased through water-soluble organic compounds released by plant residues. However, it is unknown if the contents of these compounds in crop residues can be modified by lime and phosphogypsum surface applications. The objective of this study was to evaluate effects of lime and phosphogypsum surface applications on the content of water-soluble cations in crop residues of rice, common bean and black oat. The experiment was carried out on a Haplorthox located in Botucatu County, São […]
Dynamics of soil nitrogen and cover crops dry matter production in the fall/winter as affected by pig slurry use
01/Oct/2006
The use of pig slurry before implanting cover crops in the fall/winter is becoming a common practice in southern Brazil, although its effects on crops and soil are still poorly investigated. The objective of the present study was to analyze the dynamics of soil N as well as to study the cover crop yields under use of pig slurry in the fall/winter. The study was developed in the growing season 2000 on an experimental area of the Soils Department of […]
Nitrogen application timing and soil inorganic nitrogen dynamics under no-till oat/maize sequential cropping
01/Aug/2006
The timing of N application to maize is a key factor to be considered in no-till oat/maize sequential cropping. This study aimed to evaluate the influence of pre-planting, planting and sidedress N application on oat residue decomposition, on soil N immobilisation and remineralisation and on N uptake by maize plants in no-till oat/maize sequential cropping. Undisturbed soil cores of 10 and 20 cm diameter were collected from the 0-15 cm layer of a no-till Red Latossol, when the oat cover crop was […]
Effect of liming and ammonium sulfate in cotton. II – Concentration of cations and anions in the soil solution and plant nutrient uptake
01/Jun/2006
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 […]
Soil temperature variation in three different systems of soil management in blackbeans crop
01/Jun/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 […]
Effect of liming and ammonium sulfate on cotton. I – Cation and anion transport in the soil
01/Jun/2006
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 […]