Green manure incorporation timing for organically grown broccoli

• Autor(a) principal: Diniz, Ellen Rúbia
• Data de Publicação: 2007
• Outros Autores: Santos, Ricardo Henrique Silva, Urquiaga, Segundo Sacramento, Peternelli, Luiz Alexandre, Barrella, Tatiana Pires, Freitas, Gilberto Bernardo de
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/7556
• topic: Brassica oleracea; Stizolobium cinereum; biological nitrogen fixation; decomposition rate; N recovery; Brassica oleracea; Stizolobium cinereum; fixação biológica do nitrogênio; taxa de decomposição; recuperação de nitrogênio

The objective of this work was to determine the effect of incorporation timing of the velvet bean (Stizolobium cinereum) (GM) on both organic broccoli yield and N status. Mineral N content in the soil, biologically fixed N recovery by broccoli, GM biomass decomposition and N release kinetics were also determined. Plots were fertilized with 12 Mg ha-1 of organic compost and received GM either at 0, 15, 30 or 45 days after transplant. Other treatments were compost (12 or 25 Mg ha-1), GM, mineral fertilizers and control (no fertilizer). The data were collected in four completely randomized blocks. GM decomposition increased mineral N content in soil as rapidly as mineral fertilizer or the supply of 25 Mg ha-1 of compost. The N half-life in GM (24 days) is smaller than the mass half-life (35 days) and the biological fixation contributed with 23.6% of N present in the aboveground biomass of broccoli. The result suggests a higher synchrony between the crop relative growth rate and N release from the GM when incorporated at crop early growth stage. The incorporation of GM until 15 days after transplanting replaces 50% of the highest compost dose, without yield loss.