Small-scale family farming is mainly rain-fed, with limited use of modern technology and inputs. When land is available, fields are left fallow to recover soil productivity. This involves regeneration of the Caatinga, which is remarkably resilient. Under these conditions, slash-and-burn agriculture is sustainable. However, such traditional farming practices are becoming increasingly unsustainable due to various factors: a) when plots are too small, fallow times, which should be more than five years, are reduced, without leaving sufficient time for the soil to recover its productivity; b) uncontrolled use of fire can cause deforestation, kill off juvenile trees and damage soil properties; c) cultivation on slopes without the adoption of soil conservation techniques leads to soil erosion and sedimentation of streams and rivers. Research shows that sediment production on dry land with native vegetation is 83.34 kg/ha while it is 329.58 kg/ha on cleared land. In new settlements, additional deforestation is inevitable and cannot be entirely prevented, but the Legal Reserves and Areas of Permanent Preservation can be maintained and the need for new clearing can be reduced by increasing productivity on land already cleared, sustainable use of the standing Caatinga and recourse to non-agricultural sources of income.
In many cases and especially where land is limited unsustainable practices are used to prepare deforested land for production. Excessive tillage, associated with poor ground cover and poorly managed irrigation, are the main triggers of processes of degradation in Sergipe’s Alto Sertao. Excessive plowing and continuous disking at the same depths in the soil preparation process causes disruption of lower layers. This transformation reduces the rate of water infiltration into the soil and root development of crops, affecting the potential productivity of agricultural systems. Introduction of exotic species of grass for pastures is also used to improve productivity of meat, milk and hides, however this depletes soil nutrients. The tall grass dries out quickly and burns much more intensely than native species. The National Space Research Institute (INPE) registered 185 fires in Sergipe in 2013. Inappropriate practices leave the soil exposed to heat and wind. Rainfall is often torrential and exposed soil is very vulnerable to surface erosion and formation of gullies. Rapid runoff reduces infiltration to feed springs and wells with groundwater, as well as reducing evapotranspiration that provides more rain farther inland. Soil loss following removal of vegetation has led to the depletion of seed banks, making recovery of native plant cover slow. Clearing and increased use of pesticides have also resulted in reduced populations of pollinators, further reducing recovery times
