ABSTRACT Grazing intensity is a preponderant factor for the success of integrated crop-livestock systems (ICLS). Management of grazing intensity impacts soil organic matter (SOM) dynamics, soil reacidification process, and amount and quality of residues added to the ICLS. Consequently, the soil mineral nitrogen (N) forms may present different behavior throughout the pasture cycle, because they are directed linked to SOM and soil acidity dynamics. This study aimed to evaluate the impact of grazing intensities and liming in the temporal variation […]

ABSTRACT Brazilian agriculture contributes significantly to nitrous oxide (N2O) and methane (CH4) emissions, so the understanding of such emissions at the field is crucial for mitigation strategies. This study quantified the impact of N application and sheep grazing on the N2O and CH4 emissions from a subtropical Ferralsol under an integrated crop-livestock (ICL) management system. In a long-term experiment in southern Brazil, gaseous fluxes were measured during a year-long cycle of ryegrass (Lolium multiflorum) plus oats (Avena sativa) winter pasture […]

The grain yield of upland rice under no-tillage has been unsatisfactory and one reason could be the nitrate/ammonium balance in the soil. Cover crops and nitrogen fertilization can be used to change the nitrate/ammonium relation in the soil and improve conditions for the development of upland rice in the no-tillage (NT) system. The aim was to study the effect of cover crops and nitrogen sources on grain yield of upland rice under no tillage. The study was carried out on […]

The transport of pollutants via runoff in agricultural areas, mainly in soluble forms, is an environmental problem, even in conservation tillage systems. The objective of this study was to evaluate losses of nitrogen and organic carbon in runoff, after applications of 0, 60, 120, and 180 m3 ha-1 yr-1 of cattle slurry to a clayey Oxisol, with 10 % slope under no-tillage and natural rainfall, in the region of Castro – PR. The application of cattle slurry did not affect […]

In spite of the high amount of N accumulated in high-yielding, short-rotation eucalyptus plantations, no significant or consistent increases in trunk volume have been observed in response to N fertilization. This experiment evaluated the effect of N fertilization on the growth and chemical composition of eucalyptus as well as its role in soil organic matter (SOM) mineralization. The field experiment was carried out in a randomized block design with three replications, in Itamarandiba- MG. Two N sources (ammonium sulphate and […]

The use of manure in agricultural system is a possibility to dispose of the waste generated in animal production, but improper use can cause environmental problems. The general objective of this study was to evaluate carbon and nitrogen concentrations and losses in runoff in four doses of liquid dairy manure (0, 60, 120, 180 m3 ha-1 yr-1) applied to a silt clay loam Oxisol with 13 % slope, in no-till with soybean, oat, corn, and wheat in crop rotation. The […]

Nitrification can lead to substantial losses of the applied N through nitrate leaching and N2O emission. The regulation of nitrification may be a strategy to improve fertilizer N recovery and increase its agronomic efficiency. The objective of this study was to evaluate the inhibiting capacity of nitrification in soil by Brachiaria species. The greenhouse experiment was conducted using pots with 10 dm3 of a Red Latosol sample. The treatments consisted of the cultivation of three forage species (Brachiaria brizantha, B. […]

Sewage sludges contain high levels of organic N. If these residues are applied in excess to soils, there is the risk of polluting the groundwater with nitrate, a product of N mineralization. For this reason, one of the criteria underlying the determination of the maximum N application rate to soils is the crop available N. This paper presents the results of a 224 day laboratory leaching study on organic N mineralization of anaerobically-digested sewage sludges from two treatment plants, namely Franca […]

The use of animal manure in agricultural systems can cause water contamination and/or pollution by nutrients, especially by consecutive applications to the same area. In view thereof, the purpose of this study was to evaluate the effect of manure and fertilizer application on NH4+, NO3–, P and K leaching. For this evaluation, undisturbed soil columns were collected from a seven-year field experiment that consisted of 12 treatments, resulting from the combinations of four doses of dairy slurry with three doses […]

In agricultural systems treated with sewage sludge, the management ought to seek an adequate N supply to plants, while avoiding nitrate enrichment because of its potential to pollute subsurface water bodies. Thus, when determining the maximum amounts to be applied to a specific crop, some sewage sludge and soil properties should be known. One is the fraction of organic N of the waste that will be mineralized (NMF) during the crop cycle. This quantity, combined with mineral N in the […]