Possibility of using Mucuna bracteata as a Cover Crop in Coconut Plantations in Low Country Intermediate Zone of Sri Lanka

Abstract

Mucuna bracteata is a legume with high biomass production and ability to cover the land rapidly. It also identified as a potential cover crop for rubber plantations. However, its potential of growing under coconut cultivation has not been investigated. Therefore, this study aimed to assess the possibility of using Mucuna bracteata as a cover crop for coconut plantation in the low country Intermediate Zone of Sri Lanka. A field experiment was carried out under 25 years old adult coconut plantation on red yellow podzolic soil. Four treatments in this experiment were, Mucuna bracteata planted in two rows in center of square {T1}, Mucuna bracteata planted in three rows in center of square {T2}, Mucuna bracteata planted in four rows in center of square {T3} and coconut without cover crop (control) {T4} and they were arranged in a Randomized Complete Block design with four replicates. Soil properties were analyzed before and 75 days after and ground cover were assessed 75 days after establishment. The highest ground coverage of (81 %) and the lowest weed density were observed in coconut with Mucuna bracteata in three rows. Mucuna bracteata planted plots had significantly (p < 0.05) lower bulk density (1.1 - 1.3 Mg / m3) than the control (1.5 Mg / m3) plots. Soil total nitrogen content of those treatments (0.20 - 0.27 %) was also higher than the control (0.16 %) and there were no significant difference between T2 and T3. According to the results of this study, it can be concluded that Mucuna bracteata could be used as a cover crop under coconut in low country Intermediate Zone of Sri Lanka. It also suggested that coconut with Mucuna bracteata planted in three rows was the most suitable planting method for coconut cultivation which gave better ground cover, lower soil bulk density and high soil nitrogen content than other treatments.