Potential use of <em>Mucuna bracteate</em> as a Cover Crop for Coconut Plantations in the Low Country Intermediate Zone of Sri Lanka

Abstract

Cover crops provide a wide range of ecological and environmental benefits. Mucuna bracteata is one of the leguminous creepers which has superior characteristics such as fast growth, high nitrogen fixation ability, high biomass production, and free from pest and diseases. While this plant has recently been used as a cover crop in rubber plantations in the Wet Zone of Sri Lanka, it has not been tested under coconut cultivation in the Intermediate Zone. Therefore, this study aimed to assess the suitability of Mucuna bracteata as a cover crop in coconut plantation in the Low Country Intermediate Zone of Sri Lanka. Four treatments tested in the experiment were, T1 - Mucuna bracteata planted in two rows, T2 - Mucuna bracteata planted in three rows, T3 - Mucuna bracteata planted in four rows in center of square under coconut cultivation and T4 - Coconut without cover crop (control). The treatments were arranged in a randomized complete block design with four replicates. Soil chemical and physical properties were analyzed at 5 cm - 25 cm depth. The ground cover, weed density and total biomass production were also evaluated in different planting systems. The highest ground coverage and the lowest weed density were observed in coconut with Mucuna bracteata in three rows at 75 days after field establishment. Mucuna bracteata planted plots had significantly lower bulk density, higher organic carbon content than the control and there was no significant bracteata planted in three rows is the most suitable planting method being able to give better ground cover, lower soil bulk density and higher soil nitrogen than other treatments. According to the results of the study, it can be concluded that Mucuna bracteata could be well grown as a cover crop under coconut in the Intermediate Zone of Sri Lanka. Also, it can be suggested that Coconut with Mucuna bracteata planted in three rows is the most suitable planting method being able to give better ground cover, lower soil bulk density and higher soil nitrogen than other treatments.