Efeito da mineralização da fitomassa de leguminosas nativas na produção de hortaliças folhosas em um solo gley pouco húmico

Abstract

Although soils of the Amazon floodplain soil have high natural fertility, nitrogen is the limiting factor for agriculture. Some studies have shown that nitrogen (N) is a major limiting nutrients for agricultural production in lowland soils of the Amazon and the provision of this could be done through atmospheric nitrogen fixation of leguminosae. This dissertation presents an innovative technology of green manuring, derived of the cutting and milling of the aerial biomass of some plants from Leguminosae family, called legume fertilizer. This study evaluated nitrogen release from chopped leaves of four native legumes species used as green manure prior to Coriander Coriandrum sativum L. and Lettuce Lactuca sativa L. production, on várzea soils in samples of a Haplic soils. The experiment was laid out in the field as totally randomized blocks with 5 treatments, with four repetitions each: várzea soils with Inga cinammomea Benth. (1), with Erythrina fusca Lour. (2), Entada polyphylla Benth. (3), Senna reticulata (Willd.) Irwin & Barneby (4) and floodplain soils only as control. Its purpose was to evaluate the characteristics: fresh weight and shoot dry weight (g), plant height (cm), number of stems per plant. The same was conducted in a greenhouse at INPA and were used five treatments, and a control (soil) and four species of leguminosae that have high potential for N fixation: Inga cinammomea, Erythrina fusca, Entada polyphylla, Senna reticulata. O An amount equivalent to 40 t.ha-1 of plant material was incorporated into 200 g of soil was incubated at romm temperature and maintained at 80% of field capacity, for a period of 0, 15, 30, 45, 60, 75 and 90 days. A completely randomized design with four replications and five treatments, comparisons between treatment means were made by Tuckey test at 5% propabilidade. In each period of incubation was determined mineral N (NH4 + and NO3-).Coriander and Lettuce production was higher with E.fusca and Inga cinammomea was that provided the greatest increases for the characteristics evaluated The mineralization of N was predominantly in the ammonium form up until 15 days, and then in the nitric form.