Teores de carbono e nitrogênio em diferentes sistemas de uso de solo dentro de sub-bacia com suinocultura intensiva

Abstract

The Brazilian pigs production has been growing annually, either to meet the demands for animal protein in the domestic market, or to export meat abroad. In Santa Catarina, swine farming is an activity practiced on small farms with diversified family farming, generally located in areas of marked declivity and with little area suitable for agriculture. The increase in pig production has generated accumulation of waste, and a destination of these wastes is the use as soil fertilizers, which is a predominant practice in regions of intensive breeding systems. However, these properties often accumulate swine manure in addition to the ability of the surrounding areas to receive such wastes. Thus successive applications of liquid swine manure (DLS) are usually made in the same growing area. The present work aims to evaluate if the addition of liquid pig slurry (DLS) interferes with the carbon and nitrogen contents present in the soil. The site of soil collection is located in the Lajeado Clarimundo Sub-basin, in Concórdia - SC. In total, 125 samples were collected for soil analysis. In the laboratory, each sample had his levels of organic carbon (C org.) and total nitrogen (total N) quantified. The results show that forest areas, superior references to carbon, nitrogen, organic matter and lower C / N, were the norm to indicate that the anthropic action had more effect on the alteration of the contents than the addition of DLS in itself. The forest areas presented the highest ranking for C org. (86.85), total N (96.66), organic matter (86.84) and the lowest value for C / N ratio (50.76). The lowest values for C org., total N, and organic matter were from the areas under cultivation (43.04, 35.58, and 38.48, respectively). The pasture areas without DLS addition had the lowest C / N ratio (97.81). It is concluded that the type of soil use is more impacting to the levels of C org., total N and the mineral C / N ratio than the addition of DLS itself. The addition of liquid pig slurry is beneficial in maintaining and increasing the organic carbon contents of the agricultural areas when compared to the areas that don’t have the addition of waste. It is also concluded that, there is no evidence of increase of total N even with the addition of DLS. The anthropic action has more influence on the maintenance and elevation of C org., Total N and C / N ratio of the soil than the application of DLS.