Uso de camas sobrepostas de suíno como fertilizante orgânico em pastagem perene sobressemeada com leguminosas

Abstract

This work had the objective to verify the effect of organic phosphate fertilization with swine deep bedding in the establishment and performance of birdsfoot trefoil (Lotus corniculatus L.) and white clover (Trifolium repens L.) oversowed in naturalized pasture. The essay was conducted in field condition, in soil with pH 5,5 and 2 mg.dm-3, in Concórdia, Santa Catarina, Brazil, in the years of 2004 and 2005. Two deep bedding types were tested: rice husk (CA), with 0,60% of P2O5, and coarse sawdust (MA), with 0,87% of P2O5, in four doses: 180 (1), 360 (2), 540 (3) and 720 (4) kg.ha-1 of P2O5; the quantities of CA was 30, 60, 90 and 120 t.ha-1 and for the MA was 20.6, 41.2, 62.2 and 82.8 t.ha-1, respectively. Two control treatments were added: mineral fertilization (180 kg.ha-1 of triple super phosphate, TSF) and absence of fertilization. Nine cuts were made at every 42 days during 16 months. The annual dry matter (DM) production was superior (P<0.05) with MA3, MA4, CA1 and CA2, from 8078 to 8275 kg.ha-1 of DM, in relation to TSP (4092 kg.ha-1 of DM). The annual legume production varied from 2305 to 5673 kg.ha-1 of DM with the organic fertilization, and the highest production (P<0.05) was obtained with 720 kg.ha-1 of P2O5 of MA in relation to 929 kg.ha-1 of DM obtained with SFT. The difference between two types of deep bedding was related to botanical composition: the MA favoured the legume performance (65-70% of the total forage production), while CA favored the grass performance. The swine deep bedding can be used for naturalized pasture improvement make it possible the establishment and production of legumes, even in moderately acid soil, enabling to double the annual forage yield