The effect of nitrogen fertilizer and harvesting frequency on yield and in- vitro digestibility of barley grass

摘要

It is theorized that barley grass (harvested as a green crop) would benefit from nitrogen (N) fertilizer applications during early reproductive growth states. This study examined the effects of fertilizer N applications (as urea) on irrigated land atdifferent rates and cutting intervals. It presents an assessment of our understanding of N nutrition of barley grass, with particular emphasis on use of urea-N fertilizer through the vegetative stage. The effect of different rates of N fertilizer (0, 50,100 and 150 kg N ha~(-1)) and harvesting frequency (2, 3, and 4-week intervals) was investigated on total dry matter (DM) production, crude protein (CP) content, in-vitro digestibility of organic matter (DOM) and DOM yield of the barley grass crop. Theresult showed that the highest rates of fertilizer application gave the greatest yield of DM and DOM and this was obtained at the longest interval between two consecutive harvesting times. In the shortest interval (15 days) between harvesting no significant (P > 0.05) increase in yield was observed. The interaction between harvesting period and the rate of fertilizer had significant (P < 0.05) effects on yields and DOM. The CP concentration in harvested forage showed a positive significant (P < 0.05) correlation with fertilizer application, and DOM showed a significant (P < 0.05) negative correlation with the length of harvesting interval.