An Inspection of the Possibility of Mechanized Urea Treatment of Cereal Straw through a Study of the Rewetting Process of Wheat Straw



Wheat straw, as an animal feed source, is of a low nutritional value, which can be enriched through a process of urea treatment. This process is the rewetting of the straw to the point of increasing its moisture content up to 30-50 percent using urea solution. The conventional method of treatment is a laborious, tedious and time consuming task. To facilitate this process some of these operations can be eliminated while employing mechanized treatment. In this method urea treatment can be accomplished simultaneously with straw being collected and compacted, through nozzles installed on a baler. For the purpose, the moisture fluctuating characteristics of rewetting straw were needed. Experiments were conducted in a completely randomized factorial design of 3 replications through urea solution sprinkling of straw by two kinds of nozzles (conical and t-jet) on a certain mass of straw (100 g), at four levels of compacted densities (5, 50, 85 and 120 kg.m-3) and three levels of flow rate (400, 600 and 800 g.min–1). The amounts of pre-drainage water content (Ma), final water content (Me), saturation moisture content (Ms) and drainage quantity (Md) for the straw were assessed at different flow rates and for different straw densities. The results of analysis of variance indicated that, density, flow rate, and nozzle type significantly affected Ma, Me, Ms and Md (P ? 0.01). Through an increase of density, the amounts of Me and Ms decreased while they increased through an increase of flow rate. A combination of 5 kg.m-3 and 800 g.min-1 with t-jet nozzle, which led to the highest water holding content along with the lowest drainage, were selected as the most proper options for mechanized urea treatment of wheat straw.