Volume 31, Number 3, 2007

No-tillage systems, associated to black oat as preceding cover crop, have been increasingly adopted. This has motivated anticipated maize nitrogen fertilization, transferring it from the side-dress system at the stage when plants have five to six expanded leaves to when the preceding cover crop is eliminated or to maize sowing. This study was conducted to evaluate the effects of soil tillage system and timing of N fertilization on maize grain yield and agronomic efficiency of N applied to a soil […]

The focus of our study were to study soil-landscape relationships in a sandstone-basalt transition lithosequence and to compare the limits of geomorphic surfaces mapped in the field with those mapped by geostatistical techniques. An area of 530 ha was mapped using GPS equipment in order to generate a model of digital elevation, which allowed for the establishment of a transection of 2.100 m from the hill top downwards. Along the transection, the altitude was measured at 50 m regular intervals […]

The aim objective of this study was to quantify the soil water storage, plant-available water and extraction of soil water by corn plants under irrigation and terminal drought. Plants were cultivated under no-tillage and conventional tillage systems. Two experiments were conducted in the 1999/00 and 2000/01 growing season on an experimental field of the Agricultural Engineering Department of the Federal University of Santa Maria. Treatments consisted of a 2 x 2 factorial scheme, in a completely randomized design, with four […]

The term soil erodibility (factor K in the Universal Soil Loss Equation – USLE) expresses the natural susceptibility of a soil to water erosion. The K factor stands for the soil loss rate per unit of rainfall erosivity (factor R in the USLE). Knowledge on the K factor, as well as about the other factors of the USLE, is important to establish soil conservation strategies since they permit the estimation of soil loss rates by water erosion under specific climate, […]

The microbial biomass is a living component of the organic matter responsive to changes caused by different soil management systems. The objective of this long-term study was to determine microbial biomass carbon and nitrogen in response to different management systems in a clayey Red Latosol cultivated with corn in the Cerrado. The field experiment was conducted on an experimental area of Embrapa Cerrados, Planaltina, in the Federal District. Eight soil management systems with different implements and periods of crop residue […]

The phosphorus cycle in the soil is controlled by physicochemical processes, such as adsorption and desorption, and by biological processes, such as immobilization and mineralization. This study was carried out to evaluate the seasonal variation of phosphorus in the soil microbial biomass (Pm) as related to rates and timing of soluble phosphate application. The experiment was carried out in May 2002 on an Oxisol under no-till for seven years, in Ibirubá, in the southern Brazil. Five rates of soluble phosphate […]

The improvement in the structural soil quality under continuous no-tillage occurs concomitantly to soil (re)acidification. Surface compaction can sometimes occur, owing to machinery traffic, which has to be corrected by soil tilling. In a 12-year experiment under different soil management systems we evaluated the time it takes to recover the initial soil physical attributes that are affected by soil tillage by the occasion of lime reapplication. The experiment was set up on a Rhodic Paleudult (Ultisol) at the Agronomical Experimental […]

The high organic matter content in sewage sludge is one of the reasons for its utilization as soil amendment. This study aimed to evaluate the effect of consecutive sewage sludge applications on the amounts of carbon, total and mineral nitrogen, pH, and bulk density in a Latossol. Two soil layers (0-0,1 and 0,2-0,4 m) were evaluated after three corn cultivations in Jaguariúna (São Paulo State, Brazil), between 1999 and 2001. The treatments consisted of three consecutive applications of two sewage […]

The spatial variability of soil chemical attributes was evaluated in a commercial plantation under conventional soil tillage in Uberlândia, state of Minas Gerais, Brazil, in 2004. The sampling grid was the Santa Rosa Farm, where the soil is classified as very clayey Red Latosol (680 g kg-1 clay). The objective was to evaluate the spatial distribution and dependence of the soil chemical attributes in a plantation under conventional soil tillage. For this purpose, soil data were collected from a grid […]

Among the possibilities of final disposal of sewage sludge, agricultural recycling has become one of the most widely used in several developed countries, and is considered the most appropriate in technical, economical and environmental terms. This study aimed at evaluating the sewage sludge residual effect on off-season corn yield on an Eutroferric Red Latossol (Oxisol). The field experiment was in a randomized block design with three replications, with treatments consisting of increasing doses of sewage sludge (0, 6, 12, 24 […]