甘肃省各草原生态区盛草期可食牧草养分含量及营养承载力评价

Evaluation of Nutrient Content and Nutritional Carrying Capacity of Edible Forage in Flourishing Period in Different Grassland Ecological Region of Gansu Province

为了解甘肃不同草原生态区盛草期可食牧草及养分含量变化,评价不同区域草地的营养承载力,分区域选择代表性样地进行地面调查并采样进行常规营养成分检测。结果表明,盛草期青藏高寒区和河西南部山区可食牧草平均CP含量分别为11.74%和11.18%,Ca含量分别为0.81%和0.78%,牧草营养价值相对较高。河西荒漠区CP和Ca含量分别为11.13%和0.85%,Ca含量相对较丰富。而中部干旱区Ca和P含量均较低,分别为0.62%和0.09%,陇东黄土高原区CP含量仅9.57%。牧草营养类型除陇东黄土高原区和中部干旱区为CN型外,其他各区域均为NC型,其中河西荒漠区为A-NC型。青藏高寒区和陇南山地区单位面积产草量和平均CP、Ca、P产量均较高,河西荒漠区最低。各区域以可消化CP产量核定载畜量,均能在一定程度上防止草场过度放牧,尤其陇东黄土高原区、陇南山地区和中部干旱区每公顷草地可降低0.21、0.30、0.11个羊单位的放牧压力。全省天然草原牧草P含量不足,需重视放牧家畜P的补饲。

In order to comprehend the changes of edible forage and nutrient content in flourishing period of forage growth in different grassland ecological region of Gansu province,evaluating the nutritional carrying capacity of grassland in different regions,representative sample plots were selected for ground investigation and samples were taken for routine nutrient detection.The results showed that the content of average CP in edible forage in Qinghai-Tibet Plateau region and mountainous area in the south of Hexi were 11.74%and 11.18%respectively,and the content of Ca were 0.81%and 0.78%respectively,forage nutritional value was relatively high.The contents of CP and Ca in Hexi desert area were 11.13%and 0.85%respectively,the content of Ca was relatively abundant.The contents of Ca and P were low in the central arid region of Gansu,which were 0.62%and 0.09%respectively,the content of average CP in Longdong loess plateau area was mere 9.57%.Forage nutrition type in the Longdong loess plateau area and the central arid region were CN type,the other regions were NC type,and Hexi desert area was A-NC type.The grass yield per unit area and average yield of CP,Ca and P in Qinghai-Tibet Plateau region and Longnan mountainous area were higher,and was the lowest in Hexi desert area.The carrying capacity of each region was calculated by digestible CP yield,which could prevent grassland overgrazing to a certain extent.The grazing pressure of 0.21,0.30,0.11 sheep units could be reduced one hectare grassland respectively in Longdong loess plateau area,Longnan mountainous area and central arid region.The content of P in natural grassland in Gansu province was insufficient,so it is necessary to pay attention to the supplementary feeding of P in pasture stock.