Emissions of CO2 and CH4 from cowpea-broccoli rotation under conventional and organic management practice

Resumen

In this study we assessed the effect of the cowpea (Vigna unguiculata) - broccoli(Brassica oleracea) rotation during two crop years on the direct emissions of CH4 andCO2 from soil. We also assessed if both cowpea cultivars (Feijão frade de fio preto andFeijão frade de fio claro) and management practices (conventional and organic)significantly influenced gas emissions. The study was randomly designed in blocks withfour replications, in plots of 10 m2. Gas samples were taken once a week using the staticgas chamber technique for each crop. In cowpea crops, CH4 and CO2 emissions presentedthe highest values in soils cultivated with Feijão frade de fio claro under both managementpractices. In the last broccoli crop, these emissions were higher under organicmanagement practice in broccoli rotated with Feijão frade de fio claro and Feijão fradede fio preto, respectively. Thus, the cowpea genotype influenced the emissions of bothgases, while the management practices affected these emissions in broccoli crops.