ABSTRACT Changes in soil management, for example by more vigorous crops, adoption of conservation tillage and optimization of fertilization, can increase soil organic carbon (SOC) and total nitrogen (TN) stocks. We hypothesized that corn – black oat rotation under no-tillage (NT) and adequate soil fertilization can increase these stocks, compared to conventional tillage (CT). This study compared these two tillage methods and organic with mineral fertilizers, regarding their effects on C and N cycling and SOC and TN stocks in […]

ABSTRACT The efficiency index (EI) refers to the ratio of nutrients mineralized/made available in the soil to the total amount of nutrients added by organic fertilizer. Therefore, understanding the EI is essential for recommendation of organic fertilization. The aim of this study was to evaluate the availability through mineralization and the efficiency index of nitrogen (N), phosphorus (P), and potassium (K) in organic fertilizers produced from cattle manure. The following treatments were evaluated in an incubation experiment under controlled conditions: […]

The use of organic fertilizers and the inoculation of mycorrhizal fungi in the cultivation of oil crops is essential to reduce production costs and minimize negative impacts on natural resources. A field experiment was conducted in an Argissolo Amarelo (Ultisol) with the aim of evaluating the effects of fertilizer application and inoculation of arbuscular mycorrhizal fungi on the growth attributes of sunflower (Helianthus annuus L.) and on soil chemical properties. The experiment was conducted at the Federal University of Rio […]

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; […]

The growing interest in the production of organic foods has intensified the demand for fertilizers with suitable characteristics to supply this production system. However, the quality of commercial organic fertilizers is, in some cases, doubtful due to the lack of analytical methodology to evaluate the products. Our study proposes a methodology based on the evaluation of the humification degree obtained by quantification of organic free radicals (OFR), which are naturally present in organic matter and can be detected by electronic […]

Phosphorus availability in samples of Aquatibia (Typic xerofluvent) and Hoda (Ultic haploxeralf) soils incubated with increasing amounts of organic materials (barley straw, cowpea plant tops, dairy manure and sewage sludge) was estimated by different chemical methods and by measuring the activity of the enzymes acid phosphatase and phosphodiesterase, at the Department of Soils and Environmental Sciences of the University of California/Riverside, from January to November of 1985. In a greenhouse study, yield of dry matter and P uptake by corn […]