COVER CROPS EFFECTS ON THE DEVELOPMENT OF UPLAND RICE UNDER ORGANIC FARMING SYSTEM

Abstract

This research was conducted in an experimental area in Santo Antônio de Goiás (16º28'S, 49º17'W and altitude 823 m), Brazil, during the months of June, 2004, and March, 2005. The upland rice variety Aimoré was used along with several cover crops aiming to evaluate leaf area, number of tillers, dry matter, and nitrogen content in the phytomass during the rice crop cycle. The experimental design was the randomized blocks one, with five treatments and four replications. The treatments consisted of different cover crops, such as velvet bean (Mucuna aterrima), sunn hemp (Crotalaria juncea), dwarf pigeon pea (Cajanus cajan), broom sorghum (Sorghun bicolor), and a check treatment with spontaneous vegetation growing among the rice plants. The leguminous plants, specially C. juncea, presented better results in tillering production, leaf area index, dry matter yield, and accumulated nitrogen content, if compared to the treatments where grasses were used as soil cover crop. It was concluded that rice presented a satisfactory development in the different soil cover treatments, specially after leguminous cultivation.

KEY-WORDS: Rice, green manure, leaf area index, dry matter.