Nitrogen fixation by groundnut and velvet bean and residual benefit to a subsequent maize crop

Pesquisa Agropecuária Brasileira

Ambate Okito¹  Bruno José Rodrigues Alves¹  Segundo Urquiaga¹  Robert Michael Boddey¹ 

[1] ,Embrapa AgrobiologiaSeropédica RJ ,Brazil

关键词: Arachis hypogaea;    Mucuna pruriens;    Zea mays;    15N natural abundance technique;    green manures;    N balance;    small-holder producers;    Arachis hypogaea;    Mucuna pruriens;    Zea mays;    abundância natural de 15N;    adubos verdes;    agricultura familiar;    balanço de N;    rotação de culturas;   

DOI  :  10.1590/S0100-204X2004001200004

来源: SciELO

【 摘 要 】

Chemical fertilisers are rarely avaiable to poor farmers, for whom the nitrogen (N) is often the most limiting element for cereal grain production. The objective of this study was to quantify the contribution of biological nitrogen fixation (BNF) to groundnut (Arachis hypogaea) and velvet bean (Mucuna pruriens) crops using the 15N natural abundance (delta15N) technique and to determine their residual effect and that of a natural fallow, on growth and N accumulation by two rustic maize varieties. The contribution of BNF calculated from delta15N data was 40.9, 59.6 and 30.9 kg ha-1, for groundnut, velvet bean and the natural fallow, respectively. The only legume grain harvested was from the groundnut, which yielded approximately 1.000 kg ha-1. The subsequent maize varieties ("Sol de Manhã" and "Caiana Sobralha") yielded between 1.958 and 2.971 kg ha-1, and were higher after velvet bean for both maize varieties and "Sol da Manhã" groundnut, followed by "Caiana" after groundnut and, finally, the natural fallow. For a small-holder producer the most attractive system is the groundnut followed by maize, as, in this treatment, both groundnut and maize grain harvest are possible. However, a simple N balance calculation indicated that the groundnut-maize sequence would, in the long term, deplete soil N reserves, while the velvet bean-maize sequence would lead to a build up of soil nitrogen.

【 授权许可】

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