Characterization of organic materials applied in intensive farming systems in Uruguay

Abstract

Although the addition of organic materials to soils is a common practice in intensive agricultural systems in Uruguay, there is little information on the composition of these materials. The aim of this study was to characterize physically and chemically the organic materials used in the horticultural areas of the country just before incorporation into the soil. During 2006 and 2007 samples of different organic materials were collected and grouped into several categories according to their origin: animal manure with or without litter, as chicken manure (Gallus gallus domesticus), poultry litter (chicken manure with rice hulls or sawdust), dairy manure (Bos taurus), dairy litter (dairy manure with the remains of forests and soil), composts and other materials, including slurry from the malting industry, and animal byproducts, such as rumen contents, wool, fur and feathers. The samples were analyzed for dry matter, density, pH, electrical conductivity, ash, lignin, polyphenols, soluble C, N-NH₄ ⁺ , and total content of macronutrients (N, P, K, Ca, Mg, S and Na) and micronutrients (Cu, Fe, Mn and Zn). The chemical and physical analysis show a great variability of the characteristics analyzed, even within the same group, explained by heterogeneity in the origin of materials and storage conditions.