Each soil tillage system has its proper characteristics, which have distinct effects on the chemical, physical and biological soil properties, and may require adaptations of fertilization recommendations and management. This study was conducted to evaluate the performance of three maize cultivars with fertilizer application before and at sowing in two soil tillage systems. The experiment was carried out at the “Faculdade de Ciências Agronômicas”, UNESP, Botucatu-SP campus, from November 2003 to May 2004, in a Dystric Nitosol (FAO). The experimental […]

The quality of commercial crop residues and green manure influences the N mineralization-immobilization rate and the respective use by subsequent crops. With the objective of evaluating N utilization by corn of N from the shoot and root system of sunnhemp (Crotolaria juncea) and millet (Pennicetum americanum) and corn straw, labeled with 15N, a green house experiment was carried out at the Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, S. Paulo, Brazil, in 5 kg pots with dystroferric Red Latosol […]

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 […]

The adaptability of maize genotypes to environments where nutrients are not readily available may be related to an adaptation to the predominance of the soil nitric and ammoniacal forms of N and to the association with beneficial microorganisms such as diazotrohpic bacteria and/or plant growth promoters. The objective of this study was to evaluate the response of two maize intervarietal hybrids to different nitrogen doses and forms as well as the effect of inoculation with A. amazonense. The experiment was […]

Nitrogen is the nutrient that is most absorbed by corn crop, influences grain yield most, and requires the most complex management. The objective of this work was to evaluate the effect of nitrogen (urea 15N) rate and split-applications, on grain yield, N fertilizer utilization and amount of soil native N absorbed by corn crop in a Red Latosol. The experiment was arranged in a randomized complete block design, with nine treatments and four replications, represented by five N rates: 0, […]

Maize is an important crop for grain production in the Center-West region of Brazil. An experiment was installed in Rio Verde (GO) in the 2002/03 growing season to evaluate the effect of doses and timing of nitrogen application on the agronomic traits of no-tillage maize. The experiment was evaluated as a 6 x 4 + 1 factorial in a randomized complete block design with 4 repetitions. The factors consisted of six nitrogen applications (before sowing; at sowing; top dressed 30 […]

The structural soil modifications caused by different tillage systems can result in more or less intense compaction, which interferes with soil penetration resistance, bulk density and porosity, influencing root growth and crop yields. The objective of this work was to evaluate the effect of compaction on particular characteristics of a Red Latosol and associate them with root growth and maize yield. The main treatments consisted of six compaction levels, induced by controlled tractor traffic and the secondary treatments of two […]

Nitrogen fertilization applied as sidedressing in corn can be optimized by considering additional soil characteristics as complementary indicators of soil N availability. The objectives of this study were to evaluate the potential use, critical level and best sampling time of the soil nitrate (NO3–-N) concentration to predict soil N availability in corn, as well as to verify if the determination of the soil ammonium (NH4+-N) concentration, in addition to NO3–-N concentration, enhances the efficiency of N availability evaluation. A field […]

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 majority of N from mineral fertilizers and cover crops is usually not used by the very next corn crop, but can be absorbed by follow-up crops. The objective of this study was to evaluate the use of residual nitrogen from urea, sunnhemp (Crotalaria juncea) and millet (Pennisetum americanum) labeled with 15N, applied to no-tillage corn in the previous growing season, in a Red Latosol of the Cerrado. The study was conducted in an experimental farm of the Sao Paulo […]