Sistemas de cultivo antecessores e doses de nitrogênio em cobertura no feijoeiro em plantio direto = cover crop systems and nitrogen topdressing on common bean in no tillage

The objective of this work was to evaluate the grass cover crop production in crop systems involving maize and Urochloa ruziziensis, and the influence of topdressing nitrogen rates in the yield and agronomic efficiency on common-bean cultivated in succession in no-tillage. The experiments were conducted in Jaboticabal-SP, in a eutrophic red latosol, in the second year of no-tillage system implementation. The IPR 139 cultivar was used in split plot design with three replications, in randomized block. The plots had been composed for three crop systems in the summer season, with maize exclusive, maize intercropped with U. ruziziensis and U. ruziziensis exclusive. The subplots had been constituted for five nitrogen rates (0, 40, 80, 120 and 160 kg ha(-1)), applied as topdressing at V4-4 in irrigated common-bean cultivated in the winter-spring season. The use of U. ruziziensis in crops systems, exclusive or intercropped with maize favors the grass cover crop production sufficiently to total soli surface covered, possibility similar grain yield compared to maize exclusive. The topdressing nitrogen application doesn't affect the common-bean yield in succession to maize and U. ruziziensis intercropped. The increase of nitrogen rates in common-bean in succession to maize exclusive improves the yield, although decreases the agronomic efficiency.

Nutrient cycling in two south-east Brazilian forests. I. Litterfall and litter standing crop

Examined litterfall and litter standing crops in Altitudinal forest (AF and Semideciduous forest (SF) at Serra do Japi, Jundiai, Sao Paulo State. Total litterfall was 7 t ha-1 y-1 for AF: 4.9 leaves, 1.8 woody, 0.13 flower, 0.16 fruits; and the total for SF was 8.6 t ha-1 y-1; 5.5 leaves, 2.1 woody, 0.5 flower, 0.4 fruits. Litter standing crop was 5.5 t ha-1 y-1 for the two forest sites studied with a turnover coefficient (K1) of 1.3 for AF and 1.6 for SF. Litterfall occurred throughout the year but was greater during the dry season (August-September); seasonality of litter and leaf fall was greater in SF than in AF. -from Author

Socio-eco-efficiency of integrated and non-integrated systems of crop, forestry and livestock in the Ipameri city, at brazilian Cerrado

Pós-graduação em Ciências Ambientais - Sorocaba

Qualidade dos processos mecanizados de semeadura e colheita na cultura da soja

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Metaheuristics for a crop rotation problem

This paper presents a mathematical model adapted from literature for the crop rotation problem with demand constraints (CRP-D). The main aim of the present work is to study metaheuristics and their performance in a real context. The proposed algorithms for solution of the CRP-D are a genetic algorithm, a simulated annealing and hybrid approaches: a genetic algorithm with simulated annealing and a genetic algorithm with local search algorithm. A new constructive heuristic was also developed to provide initial solutions for the metaheuristics. Computational experiments were performed using a real planting area and semi-randomly generated instances created by varying the number, positions and dimensions of the lots. The computational results showed that these algorithms determined good feasible solutions in a short computing time as compared with the time spent to get optimal solutions, thus proving their efficacy for dealing with this practical application of the CRP-D.

Comparação do custo de produção do crambe (Cambe abyssinica Hochst) com outras culturas oleaginosas em sistema de plantio direto

Biodiesel is a reality in Brazil, due to the National Program of Biodiesel Production and Use (PNPB), which became mandatory in 2008 in adding 2% biodiesel in all diesel sold in a blend known as B2. The agribusiness sector responded to the federal program, facing many difficulties in biodiesel production, which highlights the supply of raw material. Problems related to biodiesel production were mainly the shortage of vegetable oil, because of demand from domestic and foreign markets, and rising prices of raw materials available for production, making this biofuel production economically feasible, even in Brazil, where agricultural production costs are among the most competitive in the world. The crambe is a specie that has aroused the interest of Brazilian producers due to oil content, hardiness, and mechanized cultivation, mainly for being a winter crop, it becomes one more option for farmers in this period. In addition, you can compose systems of crop rotation as well as being used as ground cover in winter. The aim of this study was to evaluate the potential for productive and cost of production of crambe, conducted in no-tillage system, to compare these parameters with other oil crops such as sunflower, canola and soybean. The trial was conducted in the agricultural year 2008 at the Experimental Farm Lageado belonging to the Faculty of Agronomic Sciences - UNESP, located in Botucatu - SP. The estimated yield was 1.507,05 kg ha-1, resulting in a production of 561,94 liters of oil per hectare. The cost of installation and conduct of crambe per hectare was R$ 875,87, resulting in a cost of R$ 1,56 per liter of oil, the lowest cost among the oilseed crops analyzed.

Acúmulo de macronutrientes e produtividade de genótipos de cártamo (Carthamus tinctorius L.) em função da adubação nitrogenada no sistema plantio direto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)