Mitigation of N2O emissions from grassland by nitrification inhibitor and actilith F2 applied with fertilizer and cattle slurry

Nitrous oxide (N2O) is involved in both ozone destruction and global warming. In agricultural soils it is produced by nitrification and denitrification mainly after fertilization. Nitrification inhibitors have been proposed as one of the management tools for the reduction of the potential hazards of fertilizer-derived N2O. Addition of nitrification inhibitors to fertilizers maintains soil N in ammonium form, thereby gaseous N losses by nitrification and denitrification are less likely to occur and there is increased N utilization by the sward. We present a study aimed to evaluate the effectiveness of the nitrification inhibitor dicyandiamide (DCD) and of the slurry additive Actilith F2 on N2O emissions following application of calcium ammonium nitrate or cattle slurry to a mixed clover/ryegrass sward in the Basque Country. The results indicate that large differences in N2O emission occur depending on fertilizer type and the presence or absence of a nitrification inhibitor. There is considerable scope for immediate reduction of emissions by applying DCD with calcium ammonium nitrate or cattle slurry. DCD, applied at 25 kg ha-1, reduced the amount of N lost as N2O by 60% and 42% when applied with cattle slurry and calcium ammonium nitrate, respectively. Actilith F2 did not reduce N2O emissions and it produced a long lasting mineralization of previously immobilized added N.

Productivity of lettuce and radish cultivations as a function of spacing and of time of establishment of intercropping

The experiment was conducted at UNESP, Jaboticabal-SP, during the period of September to November of 2000, with the objective of evaluating the productivity of the cultivation of lettuce and radishes as a function of spacing between plants and of the time of establishment of intercropping. The experimental design was a completely randomized blocks and four replications. The 14 treatments consisted of combinations of spacing between lines (0.30 and 0.40 m), cultivation systems (intercropping and monoculture), and time of sowing of radish seeds to establish intercropping (0, 7 and 14 days after transplant of lettuce). The cultivars of lettuce and radish were, 'Tainá' and 'Crimson Gigante', respectively. A greater yield of commercial radish roots was obtained with intercropping cultivation. The fresh mass of lettuce in monoculture did not differ from that produced with intercropping. These results suggest that intercropping cultivation between these species is advantageous.

Comportamento ingestivo de cordeiros em terminação a pasto

The objective of this study was to evaluate intake behavior of lambs in pasture systems: (1) lambs kept with their dams in ryegrass (Lolium multiflorum Lam.) without supplementation; (2) lambs kept with their dams in the same pasture but supplemented in creep feeding; (3) lambs kept with their dams in the same pasture but supplemented in creep grazing with white clover. Three evaluations of intake behavior were performed to check the activities carried out by animals (grazing, rumination, suckling and other activities). Grazing, rumination and other activities times were different (p < 0.05) for non-supplemented lambs. For these lambs, grazing and rumination times were longer than other activities time compared to other systems. Creep feeding reduced grazing time (p < 0.05), probably due to easy access and quality of concentrate. Lambs in creep grazing had reduced (p < 0.05) rumination time. Bite mass in creep grazing was higher (p < 0.05), probably due to easy harvesting of leaves by lambs. It was concluded that the production system affects feeding strategy of lambs and the preference for legumes suggests the use of creep grazing for finishing lambs.

Estudo da herança da resistência ao crestamento gomoso do caule em melancia

Pós-graduação em Agronomia (Horticultura) - FCA

Análise de produtividade e rentabilidade das culturas de pimentão, repolho, rúcula, alface e rabanete em cultivo consorciado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Coeficiente de cultura e lâmina ótima de irrigação para a melancia, na microrregião de Teresina, Pi

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito de produtos alternativos no controle de oídio e Bacillus spp. como promotores de crescimento da soja

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Beta-lactamase detection in Staphylococcus aureus and coagulase-negative Staphylococcus isolated from bovine mastitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)