CNCPS评定毛乌素沙地荒漠化草原区常见牧草营养价值的研究

Evaluation on Nutritive Value of Some Common Forage Grasses in Desert Steppe Area of Maowusu Sandy Land Using CNCPS

为了更好地评估毛乌素沙地荒漠化草原区常见牧草的整体营养水平,采集毛乌素沙地荒漠化草原区春、夏、秋、冬四季的主要牧草品种,并进行常规营养成分分析。夏季牧草品种最全、产草量高、放牧时间长,且牧草营养价值高,因此,对夏季的牧草品种应用康奈尔净碳水化合物—蛋白质体系(CNCPS)对碳水化合物和蛋白质成分进行分类分析,并比较了CNCPS分析方法测得可降解蛋白含量(SCP)和饲料概略养分分析方法测得蛋白含量(CP)间是否存在不一致性。结果表明,毛乌素沙地荒漠化草原区常见牧草品种干物质率从春季到冬季均显著提高(P<0.05);四季的蛋白质含量差异较大,且除委陵菜外,从春季到冬季均逐季下降;中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)大部分呈上升趋势,且差异较大。夏季芨芨草、羊草、委陵菜、寸草苔及旋复花间测得的SCP和CP均呈现不一致性。说明CNCPS能够更准确和细致地反映饲草料的特性,为草场的科学利用提供了基础理论数据。

In order to give an overview on nutritive value of some common forage grasses in desert steppe area of Maowusu Sandy Land, the samples of the forage grasses mainly observed in this region were collected in the four seasons, respectively, and their normal nutritional components were determined and statistically analyzed. In summer, there were complete varieties of forage grasses, higher grass yield, longer grazing duration, and higher grass nutritive value. Accordingly, the carbohydrates and proteins of the grass samples collected in summer were subjected to classification analysis by using Cornell net carbohydrate and protein system（CNCPS）. Furthermore, the existence of difference between the content of biodegradable protein（SCP） determined by CNCPS analysis method and the content of protein content（CP） evaluated by feed proximate analysis protocol was identified. The results showed that the dry matter rate of the main forage grasses in desert steppe area of Maowusu Sandy Land was observed to follow an elevating trend from spring to winter（P 〈0.05）; the protein content of the grasses varied greatly between the four seasons, except for Potentilla chinensis, it showed a gradually decreasing tendency in the other tested forage grasses from spring to winter; the neutral detergent fiber（NDF） and acid detergent fiber（ADF） were generally increased from spring to winter and expressed seasonal variations. The difference in SCP and CP were found in the samples of Achnatherum splendens, Leymus chinensis, Potentilla chinensis, Carex duriuscula, and Flos inulae collected in summer. The combined data suggest that the nutritional characterization of forage grasses using CNCPS is more accurate and detailed. Our results provide basic theoretical data for the scientific utilization of grassland.