The soil incubation methods can be used as tools to a better evaluation of N mineralization and availability. The objective of this study was to evaluate the potential and net soil organic N mineralization, and relate them to N availability to plants. Twenty two soil samples (0-20 cm) were incubated at 35 ºC for 30 weeks in aerobic conditions and at 40 ºC for seven days in anaerobic conditions, and tested in a greenhouse experiment on corn plants. During the 30 weeks-incubation period […]

Inadequate soil management has led to the degradation of physical, chemical and biological soil properties. The purpose of this work was to evaluate the yields and physical and chemical soil properties of a dystropherric Red Latosol (Oxisol) in the third year of a crop rotation that included green manures, with soybean or corn (summer) and common bean (winter) crops. The following green manure species were used: velvet bean, millet, sunnhemp, pigeon pea, cultivated under conventional tillage and recently adopted no-tillage. […]

Insights on the variability of soil fertility in cultivated areas can contribute significantly to a rationalized use of fertilizers and soil amendments. The objective of this study was to determine the soil fertility variability through the fractionation of a commercial corn field into small management cells. The study was carried out on the farm Alto Alegre, Planaltina, GO, Brazil, on an Oxisol previously under Cerrado (savannah) in an area of 373 ha under corn in the 2003/2004 growing season. A polygon […]

The no-tillage system improves the structural soil quality. However, machinery traffic can cause surface soil compaction. In this situation, soil tilling for lime incorporation not only corrects soil acidity problems, but also decreases possible negative effects of soil compaction. The effects of tilling or not tilling the soil at the moment of lime reapplication on physical attributes in the soil profile and crop yields under different soil management systems were therefore evaluated. A long-term experiment was conducted on a Rhodic […]

This study was carried out from 1994 to 1998 in the Agronomy experimental area at the University of Cruz Alta – UNICRUZ, Cruz Alta, State of Rio Grande do Sul, Brazil to evaluate the influence of five soil management systems on bulk density, porous space (total porosity, macro and microporosity) of an clayey Rhodic Hapludox, as well as their effect on soybean, wheat and corn yield. The experiment had a completely randomized block design with four replications. The following management […]

Zinc solubility in fertilizers (zinc sulfate, zinc oxide, metallic zinc and four FTE) was determined using water, 20 g L-1 citric acid, neutral ammonium citrate (1 + 9) and DTPA as extractant solutions, and the correlation with the availability of this micronutrient for rice and corn plants established. Zinc was most accessible for the plants in sulfate form, followed by oxide, while FTE presented the lowest availability. Neutral ammonium citrate (1 + 9), at a ratio of 1:100 and after […]

The use of legume cover crops contributes to soil conservation and would be an economical N source to maize. Since only winter legumes were evaluated in southern Brazil, this study was carried out to assess the effect of four intercropped summer species (Canavalia ensiformis, Cajanus cajan, Stizolobium niveum and Glycine sp.) on N supply and maize yield increase, in comparison with a control treatment, without legume cover crops. Cropping system effects on maize crop were evaluated under three mineral N […]

Urea and uan were side-dressed applied on the soil surface and incorporated (5-7 cm) to corn in a no-tillage system to study the balance of urea-N (15N) at harvest and measure the accumulated losses of NH3-N derived from these sources and from urea + KCl (solid) and uan + KCl (liquid), applied as 06-00-09 (N-P2O5-K2O) to the surface only. The treatments-originated from a factorial 1 + (2 x 2) + 2, with plot being + factorial 2 x 2 (two […]

In order to evaluate organic N availability to oats and corn, a microplot experiment was carried out using 20 types of soil from Rio Grande do Sul State, Brazil. Microplots consisted of 20 L soil plastic pots with free drainage, maintained in an open area, with supplemental irrigation when necessary. N taken up by oats (Avena strigosa) and three corn (Zea mays) crops grown in successions was evaluated. Soil total-N and organic matter contents were initially determined as well as […]

The objective of this work was to investigate the effect of increasing closes of Irati lime on the contents of Cu, Fe, Mn and Zn both in soil and the corn plant. Irati lime is a by product obtained by Petrobras Six during the oil shale mining process, presenting high levels of micronutrients. The experiment was conducted in a greenhouse using pots filled with soil from a “Cambisol Tb” A horizon, of a sandy texture. The treatments were arranged in […]