Nitrogen symbiotically fixed by cowpea and gliricidia in traditional and agroforestry systems under semiarid conditions

Pesquisa Agropecuária Brasileira

Júlio César Rodrigues Martins¹  Ana Dolores Santiago De Freitas¹  Rômulo Simões Cezar Menezes¹  Everardo Valadares De Sá Barretto Sampaio¹ 

关键词: Gliricidia sepium;    Vigna unguiculata;    biological nitrogen fixation;    natural abundance;    15N.;    Gliricidia sepium;    Vigna unguiculata;    fixação biológica do nitrogênio;    abundância natural;    15N;   

DOI  :  10.1590/S0100-204X2015000200010

来源: SciELO

【 摘 要 】

The objective of this work was to estimate the amounts of N fixed by cowpea in a traditional system and by cowpea and gliricidia in an agroforestry system in the Brazilian Northeast semiarid. The experiment was carried out in a randomized complete block design, in a split-plot arrangement, with four replicates, in the semiarid region of the state of Paraíba, Brazil. Plots consisted of agroforestry and traditional systems (no trees), and split-plots of the three crops planted between the tree rows in the agroforestry system. To estimate N fixation, plant samples were collected in the fourth growth cycle of the perennial species and in the fourth planting cycle of the annual species. In the agroforestry system with buffel grass and prickly-pear cactus, gliricidia plants symbiotically fix high proportions of N (>50%) and contribute with higher N amounts (40 kg ha-1 in leaves) than in the traditional system (11 kg ha-1 in grain and 18 kg ha-1 in straw). In the agroforestry system with maize and cowpea, gliricidia plants do not fix nitrogen, and N input is limited to the fixation by cowpea (2.7 kg ha-1), which is lower than in the traditional system due to its lower biomass production.

【 授权许可】

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