Initial growth of two forage leguminous species as controlled by nutrient and water availability

Abstract

The soils of the semi-arid region of northeast Brazil are deficient in P and K, the former generally being the most limiting nutrient. The objective of this work was to evaluate dry matter production and P and K uptake by two leguminous tropical trees in relation to soil type, organic amendment and water availability, during 90 days in a greenhouse experiment. The experiment was conducted in a completely randomized design with treatments in factorial arrangement, with four replications. Treatments consisted of two levels of water availability (0.1 - 0.5 and 0.1 - 1.2 MPa), two species, ‘gliricídia’ (Gliricidia sepium) and ‘jurema preta’ (Mimosa tenuiflora (Willd.)), two soils (Luvissolo and Neossolo) and two doses of goat manure (with and without application). In general, ‘gliricídia’ had higher biomass production. However, this species was more susceptible than ‘jurema preta’ to soil nutrient deficiencies, which were greater in the Neossolo, and to available water limitations. On the other hand, in the more fertile Luvissol, or with organic amendmends, ‘gliricídia’ produced
significantly higher biomass than ‘jurema preta’. ‘Gliricídia’ was able to use 59% of P and up to 83% of the K present in the goat manure.