Volume 24, Number 4, 2000

With the increase of corn cultivation under the no-tillage system, various cover crop species have been evaluated to obtain a soil cover that benefits corn under succession and no-tillage. The objective of this work was to evaluate the effect of three sowing densities of black oat (Avena strigosa Scheig) and common vetch (Vicia sativa) in associated crops and as isolated crops and three levels of nitrogen fertilization (N), applied on corn (0, 60 and 160 kg ha-1 of N). Dry […]

Based on the hypothesis that antecipating of nitrogen application can increase corn grain yield due to more N availability in the initial stages of development, field studies were conducted for three agricultural years (1996/97, 1997/98, and 1998/99) to evaluate different types of management of N application for corn cultivated after winter soil cover crops. This work was developed on a Hapludalf soil, at the experimental area of the Soil Science Departament at the Federal University of Santa Maria (RS, Brazil). […]

An experiment was carried out at the Instituto Agronômico (SAA-SP) Experimental Station, in Piracicaba-SP, from March/94 to April/95, to evaluate the potential of velvet bean (Mucuna aterrima) green manure and urea, applied alone or combined, to supply nitrogen to corn crop. The experiment consisted of a preliminary phase for the production of velvet bean under field conditions and for the production of green manure labeled with 15N under greenhouse conditions. The green manure was later incorporated to the soil and […]

The leaching of nitrates and the metals K, Ca, Mg, Cd, Cu, Cr, Ni, Pb and Zn were evaluated in an experiment using biosolids amended soils. The experiment was arranged in a completely randomized block design with four treatments: Typic Hapludox with and without biosolids (LA and LA + sludge) and Rhodic Hapludox with and without biosolids (LV and LV + sludge) and four replications. Biosolids were applied to soils every two months in an average rate corresponding to 78 […]

The boron supply to plants can be accomplished by the soil, by foliar application or by treatment of the seeds. Seed treatment advantages are: application uniformity, readiness for plant use and reduction of the application costs. Theoretically, the initial reserve of boron can be increased by application in the seeds. However, high boron concentrations close to the seeds interfere with germination. The objective of this experiment was to evaluate the germination of seeds treated with increasing doses of B and […]

The aim of this study was to evaluate the effects of soil organic matter on the sorption and desorption of glyphosate in three soils with different mineralogical attributes. The experiments were carried out at the Laboratório de Ecotoxicologia of the Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). The soils were classified as: Rhodic Kandiudalf (NVef), Anionic Acrudox (LAw) and Typic Humaquept (G). In order to evaluate the influence of organic matter on the ghyphosate sorption, the soils […]