The less oxidative environment in soils of no-tillage systems decreases the humification degree of organic matter. To test this hypothesis, the concentration of semiquinone free radicals (SFR) of organic matter from the surface layer (0 to 25 mm) of a Humic Cambisol (Lages, Santa Catarina State) was evaluated. The soil had been cultivated for 8 yrs under conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). The SFR concentration in organic matter was assessed by electron spin resonance (ESR) in the granulometric […]

Inadequate crop practices are among the main causes for reduced productivity of cashew crops in the Northeast of Brazil. Periodical elimination of vegetation and the use of heavy machines and implements influence soil temperatures and density, possibly affecting plant growthand development. This is an aggravating fact, considering the sandy soils and climate conditions of the region. This study had the objective to investigate the development of cashew nut plants (early-dwarf cultivar) at different levels of soil temperature and density, to […]

This study was conducted at the Experimental Station of the Faculdade de Engenharia (UNESP), Ilha Solteira County, Mato Grosso do Sul State, Brazil, with the aim of evaluating chemical modifications in a Red Latosol under cerrado, subjected to different use and management systems. A completely randomized design with six treatments and 10 replications was used. The treatments of use and management were: no-tillage with annual crops, conventional system with annual crops, minimum tillage with annual crops, native vegetation (cerrado), pasture, […]

All anthropic action causes changes in the environment. The objective of this study was the evaluation of alterations on the physical properties of a typical Brazilian Oxisol, caused by agricultural soil management. Undisturbed soil samples were collected along a 1m top layer of the soil profile in three use and management systems: natural forestry, non-irrigated and irrigated. These samples were used to determine the soil water retention curves and then the soil pore size distribution. After flooding, the aeration porosity […]

The porosity characteristics of a Red-Yellow Podzolic was evaluated after 10 years of cultivation, under the following soil management treatments: no-tillage, moldboard plowing + disking, disk plowing + disking, off-set disk harrowing followed by moldboard plowing + disking, off-set disk harrowing followed by disk plowing + disking and off-set disk harrowing followed by disking. Undisturbed 15 cm high and 15 cm deep soil blocks, were sampled for morphometric analysis of the soil porosity. Results indicated the presence of surface sealing […]

The GIS-IDRISI was used to check land use adequacy from 1997 to 1998, in the initial part of the Rio Pardo basin, in Botucatu/Pardinho (SP), to obtain a suitable land use planning of the area. The classes and subclasses of land capability were determined according to the Land Capability Classification System. The lands of the studied area were classified as: class VIe, lands with erosion susceptibility (90.49%); class Va, flat lands, with no erosion risk, but limited by excess of […]

This study analyses the correlations among erosivity parameters and soil losses, between June 24, 1979 and October 10, 1994, in an Oxisol from the Unidade de Execução de Pesquisa de Âmbito Estadual at Dourados – EMBRAPA, Southern Mato Grosso, Brazil. Rainfall erosivity, runoff, and rainfall-runoff parameters were analysed through simple and multiple linear regression and nonlinear regression, to: (a) define an erosivity parameter for individual storms, aiming to improve the use of the USLE at that site; (b) obtain the […]

Soil is an important component of the ecosystem. Its management affects air and water quality. Nowadays, the soil potential to sequester carbon and, therefore, mitigate global warming, is an emergent subject. The main goals of this research were: (a) to evaluate the potential of cover crops (black oat, blue lupine (priori to oat + vetch), velvet bean and jack bean) used in corn production systems to increase soil organic carbon (OC) and total nitrogen (TN) content in a sandy-loam typic Paleudalf, in […]

Microbial biomass plays an important role in phosphorus cycling in tropical and subtropical soils. The purpose of this research is to quantify the content of phosphorus stored in the microbial biomass in soils under different tillage and cropping systems. Four long term experiments were then used, involving no-tillage and conventional tillage and different crop rotations, installed in different soils (Heavy clay Rhodic Hapludox, Clay Rhodic Hapludox and fine-loamy Rhodic Paleudult) in the state of Rio Grande do Sul – Brazil. […]

Corn requires a high uptake of nitrogen. Because soil has a limited capacity to supply this N demand, other N sources as legumes and mineral fertilizers are used. Potentially, the association of these sources of N can contribute to agricultural sustainability. This work was carried out to evaluate the impact of tillage and cropping systems on N availability. A long-term experiment established on a Paleudult at UFRGS (RS), Brazil was used. This experiment had three tillage systems: conventional, minimum and […]