The use of spontaneous species of the Caatinga as green manure is a management technique alternative to vegetable production in northeastern Brazil, but information are still scarce. This study was carried out during October-December 2009 in Mossoró, Rio Grande do Norte state, Brazil, in order to evaluate the effect of three spontaneous species of the Caatinga at different doses of biomass on the soil microbiological attributes and yield of radish. The experimental design was in randomized complete blocks with three replications and the treatments composed of three species of the Caatinga [hairy woodrose (Merremia aegyptia); oneleaf senna (Senna uniflora) and roostertree (Calotropis procera)] used in five doses of dry mass (5.4, 8.8 , 12.2, 15.6 and 21.0 t ha-1). The microbiological characteristics evaluated in soil were: the number of colony forming units (CFU) of actinomycetes, fungi and bacteria and in the radish were the total and marketable productivity, root dry mass, dry mass of shoots and percentages of marketable and disposal roots. The growth of microorganisms in the soil was not affected by the species, but there was an increase in the number of CFU of microorganisms with the doses applied (1.025 x 10(4) for actinomycetes, 7.995 x 10² for fungi and 7.841 x 10(6) for bacteria). The highest total and marketable yields and amount of dry mass of shoots of radish were obtained with 21.0 t ha-1 of biomass hairy woodrose. Higher percentages of marketable and disposal roots of radish were recorded in the hairy woodrose and oneleaf senna species. The maximum percentages of marketable roots and minimum percentage of disposal roots were obtained with the incorporation of 21.0 t ha-1 biomass of green manures.
Raphanus sativus; Merremia aegyptia; Senna uniflora; Calotropis procera; tropical thorn forest; soil microorganisms
