Sisal was grown in double rows with broad-interrow covers of Pueraria phaseoloides, controlled volunteer vegetation or clean weeding. Clean weeding gave the best yield over one cycle, but Pueraria cover was best in the second cycle. Pueraria was better than volunteer vegetation in all trials, with the greatest margin on soils low in nitrogen, or where there were pernicious weeds. On an exhausted soil, sisal with a Pueraria cover responded to fertilizer nitrogen applied in the early or late part of the cycle. Manuring sisal growing with a volunteer vegetation cover with 50 tons sisal waste/ha. improved growth to the same extent as replacing the cover with one of Pueraria. In the absence of manures, yields declined from cycle to cycle with all the covers. At the level of manuring which maintained yields with a volunteer vegetation cover, yields declined slightly with clean cultivation, and improved considerably with a Pueraria cover.