Nitrogen (N) is required in large quantities by corn and its supply causes technical concerns related to crop performance and profitability, and environmental concerns in view of the high risk of nitrate leaching. Results of 61 field experiments conducted through 13 years, in a cooperative effort of the Fundação Agrária de Pesquisa Agropecuária (FAPA) and the Universidade Federal do Rio Grande do Sul (UFRGS), were analyzed and interpreted aiming at establishing a N fertilizer indication for high corn yields, adjusted […]

Decomposing crop residues in no-tillage system can alter soil chemical properties, which may consequently influence the productivity of succession crops. The objective of this study was to evaluate soil chemical properties and soybean, maize and rice yield, grown in the summer, after winter crops in a no-tillage system. The experiment was carried out in Jaboticabal, SP, Brazil (21 ° 15 ‘ 22 ” S; 48 ° 18 ‘ 58 ” W) on a Red Latosol (Oxisol), in a completely randomized block design, in strip plots with three replications. The treatments consisted of […]

Nitrogen is the nutrient required in the largest quantity by plants and is generally the most limiting nutrient for crop yield. The objective of this research was to evaluate the effect of cropping systems on N accumulation and availability in the soil. A long-term experiment (22 years) was conducted on a Paleudult soil at an experimental station of the Federal University of Rio Grande do Sul (30 º 50 ‘ 52 ” S and 51 º 38 ‘ 08 ” W), in Eldorado do Sul, Brazil, established in 1983. The experiment consisted […]

Soil management can have effects on nutrient availability and fruit yield. The objective of this study was to evaluate the effect of phytomass management forms of different cover crop species on soil chemical properties related to organic matter, nutrient availability, and on grapevine yields. The experiment was carried out in Embrapa Uva e Vinho, in Bento Gonçalves, RS, in Southern Brazil, on a Haplic Cambissol, in a vineyard established in 1989, using White and Rose Niagara grape in a horizontal […]

The use of cover crops preceding corn is an alternative to supply nitrogen (N) and to make no-till system viable regions with dry winter such as in the Southeast, Center-West, North, and Northeast of Brazil. The purpose of this study was to evaluate N levels and the effect of cover plants on N supply and corn yield in no-till system. The study was carried out from 2000 to 2003. The experimental design was randomized blocks, with split-split plots and four […]

Compaction is one of the main causes of yield decreases in agricultural soils. Mechanical chiseling has been suggested to reduce soil compaction in long-term no-tillage systems. Another option to alleviate soil compaction is the use of cover crops, such as forage radish, with a well-developed tap root system and the capacity of growing into soil compacted layers, forming stable biopores and improving the soil physical properties. This study aimed to evaluate the efficiency of a mechanical (chisel plow) and biological […]

The objective of this study was to compare, in compacted soil condition, the aggregate stability after different crops rotations under no-tillage system and chiseling. The following crop rotations were repeated for three consecutive years under no-tillage: triticale (X Triticosecale Wittmack) and sunflower (Helianthus annus) as autumn-winter crops, together with pearl millet (Pennisetum glaucum), forage sorghum (Sorghum bicolor) and sunn hemp (Crotalaria juncea) in spring, preceeding soybean (summer crop). In the chiseling treatment the area was kept bare between the autumn-winter […]

Chiseling and cover crops can be used in the management of orchards with the purpose of improving soil physical conditions and reducing soil compaction. This study had the objective of evaluating the influence of chiseling on the development of cover crops and citrus trees and on soil physical properties in an orchard with a compaction history in a clayey Typic Haplorthox. The soil was chiseled at 0.30 m, followed by three soil cover crops: spontaneous vegetation, pigeon pea (Cajanus cajan), […]

The objective of this experiment was to compare the ability of soybean (Glycine max), corn (Zea mays), Brachiaria brizantha cv. Marandu and pearl millet (Pennisetum glaucum) for P-uptake, at different levels of the Alvorada natural rock phosphate, under controlled conditions. The soil used was a dystrophic Hapludalf (180 g kg-1 clay), which was limed and fertilized with N, K and micronutrients. The crops were grown in 18 dm3 pots for 50 days in a greenhouse, at different P2O5 rates (0, […]

Carbon (C) addition through crop residues (residue-C), C dioxide emission (CO2-C) and the soil C stock (soil-C) are components of the C cycle in the soil-plant-atmosphere system. This 18-year study was conducted to identify agricultural practices that could potentially increase C retention in the soil and lessen global warming trends. The three C pools (residue-C, CO2-C and soil-C) under different tillage systems (CT-conventional tillage and NT-no tillage) and cropping systems (O/M-oat (Avena strigosa Schreb)/maize (Zea mays L.) and V/M-vetch (Vicia […]