This paper describes a technique that retrieves soil moisture from monopolarized SAR data. The technique uses SAR data obtained by the Japanese Earth Resources Satellite (JERS-1) and two empirical models. One relates the backscatter coefficient with the complex permitivity (Dubois’s model), and the other relates the complex permitivity with soil parameters such as soil moisture (Hallikainen’s model). First, the SAR data were calibrated to obtain the backscatter coefficient and the Dubois’s model was inverted to achieve the complex permitivity. The […]

The impact of winter cover crops prior to no-tillage corn on aggregate stability was evaluated throughout the agricultural year of May 1991 – May 1992, in a Hapludalf (Red-Yellow Podzolic). The experiment was carried out at the Federal University of Santa Maria-RS, using the following winter cover crops as treatments: Lathyrus (Lathyrus sativus L.); Lupine (Lupinus angustifolius L.); hairy vetch (Vicia sativa L.); black oat (Avena strigosa Schieb) and winter bare soil. Water aggregate stability, organic carbon, microbial activity, soil […]

The present study was carried out in 1995 to investigate why plants cultivated in a Red-Yellow Podzolic in the State of Acre, in the Brazilian Amazon, presenting high amounts of exchangeable aluminum, have not shown symptoms of toxicity to this element or yield reduction. The exchangeable Al3+ in the B horizon is higher than 14 cmolc dm-3. Samples of the A and B horizons were incubated with increasing rates of lime and subjected to determination of pH in H2O, pH […]

Soil in natural conditions are in steady state in the environment. However, inadequate management can cause degradation mainly in the organic matter fraction, impiring the sustainability of agricultural systems. This experiment was conducted for 6 consecutive years in a Hapludalf (Red Yellow Podzolic Soil), at the experimental area of Soil Science Department UFSM. The objective was to evaluate the effects of plant successions on the carbon dynamic. The plant successions used were common vetch (Vicia sativa)/corn (Zea mays), blue lupine […]

Alternative methods to correct soil acidity are needed because farmers who adopted no-tillage no longer want to plow soils to incorporate lime. Two experiments were carried out during the years 1993-1996 under no-tillage to evaluate the response of soybean, wheat, corn, oat and barley to lime applied on the surface of soils with 380 g kg-1 clay (LEd-Haplorthox) and with 580 g kg-1 clay (LRd-Haplorthox). A completely randomized block design, with three replications and seven treatments, was used. The treatments […]

Despite the fact that aluminum toxicity to crops is eliminated near soil water pH of 5.5, lime recommendation in many regions aims to increase soil pH up to 6.0 or even higher. For highly buffered soils, high rates of limestone are required to raise the pH from 5.5 to 6.0, resulting in additional, sometimes unnecessary, costs. The objective of this study was to evaluate the effect of soil pH on corn yield in a very acid Hapludox. The experiment was […]

The effects of soil preparation systems and doses of nitrogen on total dry matter, straw and grain production and on nitrogen accumulation by corn plants (Zea mays L.) cultivated under irrigation were evaluated in a field experiment in a Dark-Red Latosol (Oxisol), originally under cerrado vegetation, at EMBRAPA/CNPMS experimental station, Sete Lagoas, Minas Gerais State, Brazil, from November, 1995 to June, 1996. The soil preparation systems studied were: no till, conventional till with disk plow and conventional till with moldboard […]

The effect of sewage sludge pelletization added at rates of 0, 1 and 5% (v/v) of dry material was studied on corn growth and absorption of Zn, Cu and Ni, with or without the addition of CaCO3 to increase soil pH to 6.0. Three Hapludox soil samples from the State of São Paulo, Brazil, “latossolo roxo”, “latossolo vermelho-escuro” e “latossolo vermelho-amarelo” (LR , LE and LV, respectively) were used in a greenhouse experiment conducted in Campinas, State of São Paulo, […]

Nitrogen mineralization potential (No) for ten Rio Grande do Sul, Brazil, soils was studied with corn grown on 20 kg pots for 45 days, as compared with nitrogen mineralized in aerobic incubation for 32 weeks. No values ranged from 108.6 to 210.8 mg kg-1, being similar to the total nitrogen mineralized. Mineralization velocity was higher during the first four weeks, and overall mineralization rate varied from 0.2985 to 0.3181 week-1 among soils. The correlation coefficient between corn absorbed nitrogen and […]

Two field experiments were carried out with corn, using no-tillage system (NTS) over oat residues, in a clay dark-red latosol at the Centro de Pesquisa Novartis – Seeds, in Uberlândia, State of Minas Gerais, Brazil, and conventional tillage system over soybean residues (CTS), in a sandy red-yellow latosol at the Santa Terezinha farm, Uberlândia. The objective of this study was to evaluate the NH3-N volatilized from nitrogen sources, side-dressed applications, of approximately 100 kg ha-1, applied in the middle of […]