Cover Crops on Weed Management in Integrated Pineapple Production Plantings

Weed control in pineapple orchards in Brazil is traditionally performed manually and by spraying herbicides, thus being rather aggressive to the environment. The objective of this work was to evaluate the effect of Cynodon dactylon and Pennisetum americanum as cover crops on weed management in pineapple orchards under integrated production system in comparison with the conventional production system. The cover crop management consisted of spraying post-emergence herbicide at blooming stage and chopping the cover crops, allowing their residues to remain on the soil as mulch, and making direct planting of the cover crops as many times as possible, depending on environmental conditions. Weed control in the conventional production system was performed by six manual interventions and four pre-emergence herbicide sprays. On the other hand, no conventional weed control was performed in the pineapple orchards where C. dactylon and P. americanum were used as cover crops. The nutritional status of the pineapple plants was evaluated based on 'D' leaf analyses prior to the flowering induction treatment. Nutrient levels were higher in plants of the cover crop treatments, showing no competition of either C. dactylon or P. americanum with the cash crop. Pineapple plants grown in association with those cover crops produced higher percentages of fruits weighing above 1,500 g than those from the treatment with conventional weed control. In addition, the treatment with P. americanum as cover crop resulted in the production of a higher number of large fruits, weighing above 1,800 g, in comparison with C. dactylon as cover crop and the conventional weed management.