Dossiê de ambiência e transição agroecológica no manejo da microbacia hidrográfica do lajeado Biguá, Alecrim - RS

Abstract

The atrophic disordinated action over an area leads to degradation of the natural resources, mainly the soil, water and native vegetation, changing the landscape, altering the ambience and bringing negative consequences to the social and economical conditions of the population. In such context, the current study had as its aims assess, through an ambience dossier, the physical-conservationist, social-economical and environmental degradation, giving priority to recuperation goals, as well as carry on a floristic survey of the riparian vegetation aiming, its recovering and a case study in family agro ecological system as an alternative way of management in the Watershed of Lajeado Biguá, Alecrim - RS. The ambiance dossier was carried on through observations and interviews with farmers of the studied micro basin. The floristic survey was done in randomly demarcated parcels along the banks of the Lajeado Biguá stream, where arboreal, herbaceous and shrub strata were sampled. In the agro ecological case study, a history of the property use was done, the current soil status was assessed and samples of the soil were taken in order to assess it main chemical and physical characteristics. The dossier results show that, among the main problems, the ones inherent to soil and water degradation stand out, mainly due to the inadequate management of this natural resources. The main cause of degradation is the soil preparation in a conventional way and the soil use in areas which should be of permanent reservation, as banks of rivers and steep areas. The degradation of riparian vegetation was caused by the use of the bank soil with crops and grazing, affecting the stream water quality and quantity and the water sources used by the population, as well as the riparian vegetation species and their natural regeneration capability. The riparian vegetation recover with the use of the species found in the floristic survey is recommended aiming its functions reestablishment. The agro ecology seems to be a viable system, mainly for small rural property, offering good productivity, crop diversification, healthy products, with higher demand and value-added smaller cost production with higher income to the producer, therefore increasing his/her social and economical conditions, being and alternative to the agricultural system in the studied micro basin. However, conservationist management ways are recommended, such as no-tillage, aiming the improvement of the chemical and physical soil characteristics, mainly the support of organic matter, which is the most affected by the conventional preparation used in the area studied and all over the watershed.