ABSTRACT One of the pillars of a no-tillage system is the addition of adequate amounts of residue to keep the soil continuously covered. Cover crops are a tool for supplying the demand for the permanence of residues on the soil surface and releasing nutrients to the soil. However, there is no index that relates these two factors and can reconcile the maximum permanence of crop residues in the soil with the maximum N supply via N mineralization of such residues. […]

ABSTRACT The combined incorporation of sewage sludge (SS) and oat straw (OS) to the soil can increase straw carbon mineralization and microbial nitrogen immobilization. This hypothesis was tested in two laboratory experiments, in which SS was incorporated in the soil with and without OS. One treatment in which only straw was incorporated and a control with only soil were also evaluated. The release of CO2 and mineral N in the soil after organic material incorporation was evaluated for 110 days. […]

The determination of the nitrogen (N) mineralization rate in waste-treated soils is important to calculate the residue rates to be applied, supplying plants with mineral N to at the appropriate time, without leaching losses. Most studies on residue-treated soils use the technique without leaching of mineral forms and the volumetric determination method. The repeatability of the test is however poor and the sensitivity of the determination method low, especially in soils amended with sewage sludge and organic compost. In this […]

The cover crops in no-till system can contribute to the formation of mulch and nutrient cycling to annual crops in succession. The objective of this study was to evaluate biomass production and nutrient cycling of cover crops sown in the second growing season, in crop rotation after upland rice and soybean, in no-tillage and conventional tillage systems, on a Red Latassol of Rio Verde, state of Goiás, from April 2008 to April 2010. The experiment was evaluated in randomized strips, […]

Currently research verified that glyphosate or ammonium glufosinate herbicides use for cover crop desiccation in conservationist systems may reduce N amount in straw. The aim of this study was to evaluate nitrogen mineralization in millet straw after glyphosate or ammonium glufosinate application and the N uptake by corn plants. A complete randomized design was used with six treatments and five replications, in a 3 x 2 factorial scheme: cover crop management (without herbicide application, glyphosate or ammonium glufosinate desiccation) and soil type […]

The C mineralization of pig manure and cereal straw is still relatively little studied in Brazil. The aim of this work was to evaluate C mineralization of oat straw, pig slurry and pig deep-litter, applied on the surface or incorporated in a Hapludalf soil, in laboratory conditions. The experiment was a completely randomized design with four replications of the following treatments: soil; soil + incorporated straw; soil + surface straw; soil + incorporated pig deep-litter; soil + surface pig deep-litter; […]

Crop residue production, plant residue maintenance and their decomposition are important factors in the understanding of nutrient recycling process. To evaluate K accumulation and release a study with eight cover crops types was developed: pearl millet (Pennisetum americanum sin. tiphoydes), brachiaria grass (Brachiaria brizantha), sorghum (Sorghum bicolor L. Moench), pigeonpea (Cajanus cajan (L.) Millsp), sunn hemp (Crotalarea juncea) and black oats (Avena strigosa Schreb), fallow land and conventional culture (control) in the experimental area of CEFET-Uberaba-MG, in a Cerrado area. […]

Evaluating the decomposition of cover crop residues added to the soil allows improving the comprehension of appropriate nutrient supply for commercial crops. This study was carried out under field conditions aiming to evaluate the decomposition and nutrient release from the shoots of perennial herbaceous legumes. The treatments were green cover crops intercropped with banana: groundnut (Arachis pintoi Krapov. & W.C. Gregory.), tropical kudzu (Pueraria phaseoloides (Roxb.) Benth.), siratro (Macroptilium atropurpureum (Sessé & Moc. ex DC.) Urb.) and spontaneous vegetation (mainly […]

Nutrient cycling in eucalypt plantation systems allows for an evaluation of eventual differences due to the applied management methods and inferences on the sustainability of plantations. The aim of this study was to evaluate possible differences in nutrient cycling and balance in eucalypt plantation systems according to the species. Stands of Eucalyptus grandis, E. camaldulensis, and E. pellita were evaluated at the age of six years, in the Coastal Plains in the north of Rio de Janeiro State (Yellow Oxisol and Argisol) […]

The aim of this work was to evaluate the nutrient input through litterfall, in one area degraded by soil remotion, replanted with ten-year-old nitrogen-fixing legume trees Acacia auriculiformis (acácia), Gliricidia sepium (gliricídia), and Mimosa caesalpiniifolia (sabiá) and another neighbor area with a secondary growth Atlantic forest (“capoeira”) fragment. The experiment was carried out at the Embrapa – Agrobiologia research station, Km 47, Seropédica, State of Rio de Janeiro, Brazil. The litterfall was quantified in litter traps with an area of 0.25 m2; […]