Intensive cattle browsing did not prevent fallow recuperation on smallholder grass-capoeira pastures in the NE-Amazon

摘要

In northeastern Para, extensive fallow-based agriculture systems are still common on smallholdings. Soil fertility is maintained by permitting the recuperation of the capoeira forest fallow. Much of the capoeira, however, has been eliminated, e.g. for permanent pastures but grass-monocultures usually ecologically degrade within a decade and lead often to barren pasturelands. To avoid these biologically degraded pastures, an innovative organic agro-forestry-system-model has been proposed, temporarily integrating pastures/cattle into the slash-and-burn cycle. The new approach assumes that cattle impact such as browsing and trampling would not alter the capoeira. This hypothesis was tested in researcher-managed on-farm experiments, by floristically comparing grass-capoeira pastures (GCP) against undisturbed capoeiras (UC) and traditional grass pastures (GP). Therefore, each pasture treatment was replicated three times on 0.36 ha pasture plots, respectively. Cattle were introduced at a stocking rate of 667 kg/ha, being reduced by one animal after 38 months to 410 kg/ha. Cattle impact was ascertained by comparing total capoeira phytodiversity, species similarity, life form structure, and vegetation cover. It was found that even intensive cattle impact on young capoeiras was neglectable and did not alter phytodiversity nor species composition. GCPs just showed a slight retardation in comparison to UC so that the botanical evidence of the ecological sustainability of a GCP could be proved. A PerMANOVA revealed that only 4.7 % (F = 5.513; RA(2)A = 0.047) of the differences between GCP and UC are attributed to the cattle impact/slashing regime. Our preliminary results suggest that the biodiverse system approach is worth pursuing as an alternative to degraded pastures.