Effects of Different Doses of Nitrogen Application on In- Situ Rumen Degradability Characteristics of Organic Matter and Crude Protein of Rangeland
Abstract: This study was conducted to investigate the effects of different nitrogen (N) fertilizer levels on organic matter (OM), OM yield, crude protein (CP) and in–situ ruminal OM and CP degradabilities of a native legume-grass mixture pasture. Pasture was fertilized at six levels of N fertilizer (ammonium nitrate), N0, N5, N10, N15, N20 and N25 kg da-1. In this study, three rumen fistulated Holstein Friesian heifers were used to incubate forage samples in-situ nylon bag technique. N fertilizer application significantly increased OM, hemiselulose of legume–grass mixture pasture and crude protein of grass (p<0.01; p<0.05). It was determined that there was a linear and quadratic positive very important relationship between OM degradability of rangeland forage and nitrogen doses (p<0.01, R2=0.39; p<0.01, R2=0.52). Besides, It was found that there was a linear and quadratic positive relationship between out flown rate (k=0.02 h-1) of CP and effective rumen degradability of CP with the nitrogen doses (p<0.05, R2=0.27).
Key words: N fertilization, rangeland, organic matter, crude protein, rumen degradability