Biomass production and leaf gas exchange of perennial legumes associated with bananas

The search management for alternatives that reduce the use of mineral fertilizers is important for agricultural sustainability. Therefore, we sought to identify two legume species that are grown as cover crops with banana (Musa spp.) cultivar Prata-ana and spontaneous plant compositions that enable further reduction in the use of inputs. A randomized block design in a split plot arrangement with five replications was used. The plots were formed at four irrigation depths: 50, 75, 100 and 125% of crop evapotranspiration. Subplots were formed by three plant cover types associated with bananas: Tropical kudzu (Pueraria phaseoloides Benth.), calopo (Calopogonium mucunoides Desv.) and spontaneous vegetation, which primarily consist of Panicum maximum Jacq. The biomass production of the cover crops was measured 105, 200 and 400 days after planting (DAP); the total input of N was also measured (105 DAP). The measurements of leaf gas exchange and relative index of chlorophyll were recorded at 200 DAP. Tropical kudzu is better acclimated to a shaded environment, as demonstrated by evaluations of dry matter production, leaf gas exchange and the input of N. Thus, this crop may be a good alternative for supplying N to bananas irrigated under Brazilian semi-arid conditions.   Key words: Water management, Musa sp., cover crops, photosynthesis.