Effects of covering the stacks when treating straw with urea.

摘要

Three lots of 100 sheaves, each 18 kg, of urea-treated durum wheat straw were not covered or covered with earth (PTct) or with plastic (PTcp) and compared with an untreated control. The treatment was carried out by applying by hand urea 50 g in water 400 g per kg DM to successive layers of sheaves. Storage was for 60 days at mean temperature 29degC. Urea treatment increased CP content from 59 to 61 g/kg DM with no effect of covering. Feed intake by sheep was greater for covered treated straw (PTcp 47.9 and PTct 46.3 g DM/kg0.75) than not covered treated straw (42.7 g DM/kg0.75). Digestibility of covered treated straw was similar (for PTcp and PTct, respectively, 57.5 and 56.2% for organic matter, 66.7 and 66.2% for crude fibre, and 61.3 and 60.8% for CP). It is concluded that covering urea-treated stacks with earth could be convenient for medium-sized stacks, while only large stacks are fit to be left uncovered.