Avaliação da disponibilidade de água e ar em substratos agrícolas à base de turfa e casca de arroz carbonizada

Abstract

The objective of this work was to evaluate the physical characteristics of alternative agricultural substrates based on peat and carbonized rice hulls. Treatments consisted of: S (25% carbonized rice hull and 75% peat), S (75% carbonized 1 2 rice hull and 25% peat), S (control - commercial Plantimax) and S (50% carbonized rice hull and 50% peat). The substrate 3 4 density (DS) was determined by the method of Hoffman (1970). To determine the characteristic curve of water retention (CWR) of the substrates the methodology of the Bureau of voltage was used. We used three replicates in the tensions of 0, 20, 40, 60, 80 and 100 hPa. Having the CWR, we calculated total porosity, aeration space, available water, easily available water, buffering and remaining water. It was found that the increase in the proportion of carbonized rice hulls added to peat raised the organic carbon of substrate, easily available water, space aeration, total porosity, available water and buffering water. The S treatment had a very low volume of remaining water, a characteristic that demonstrates that the increasing 2 addition of hulls promotes more rapid release of water, reducing the contents of buffering and remaining water. Due to its low capacity for water storage, the S treatment requires frequent irrigation.