Soil attributes of a silvopastoral system in Pernambuco Forest Zone
This research evaluated soil properties in a silvopastoral system using double rows of tree legumes. Treatments were signalgrass (Brachiaria decumbens) in monoculture or in consortium with sabiá (Mimosa caesalpiniifolia) or gliricidia (Gliricidia sepium). Treatments were arranged in a complete randomized block design, with 4 replications. Response variables included chemical characteristics and physical attributes of the soil. Silvopastoral systems had greater (P<0.001) soil exchangeable Ca (gliricidia = 3.2 and sabiá = 3.0 mmolc/dm3) than signalgrass monoculture (2.0 mmolc/dm3). Water infiltration rate was greater within the tree legume double rows (366 mm/h) than in signalgrass (162 mm/h) (P = 0.02). However, soil moisture was greater in signalgrass pastures (15.9%) (P = 0.0020) than in silvopastures (14.9 and 14.8%), where soil moisture levels increased as distance from the tree rows increased. Conversely, the light fraction of soil organic matter was greater within the tree legume double rows than in the grassed area (P = 0.0019). Long-term studies are needed to determine if these benefits accumulate further and the productivity benefits which result.
Keywords: Fertility, legumes, soil physics, trees.