THE RELATIONSHIP BETWEEN SPECIES DIVERSITY AND NITROGEN CYCLING IN PASTURE

生物多样性研究不仅对群落生态学具有重要意义，而且对应用生态学也具有重要意义。我们想知道生物多样性的程度是否会影响牧场氮素循环的效率。许多科学家表示，生物多样性与生产有着密切的关系。如果生物多样性与产量呈正相关，则生物多样性高的生态系统具有较高的氮素循环等母体循环能力。然后，从管理对生物多样性的影响、生物多样性与氮素循环的关系两个方面了解牧场生物多样性的滚动情况。氮素损失量由牛奶、化肥和饲料谷物中的氮量计算，用于环境影响。为了测量从牛尿到牧草生产中氮的回收效率，我们在另一个实验中使用了15N标记的尿液。T…部分奶农低投入牧场的种植多样性高于高投入牧场。植物和土壤壁虱多样性之间存在着很强的相关性。单位牧场产奶量的成本效益分析结果表明，产奶量存在最优投入。许多养殖户将达到最佳点，这意味着牛奶生产的高效率。单位牧场的产奶效率与生物多样性呈正相关。利用15N标记法估算了牛尿中氮对牧草生长的回收率为37.37%~78.51%。因此，氮素损失在20%~60%之间。约20%的氮素损失来自于少量的尿液。大约60%的氮素损失来自大量的尿液。结果表明，氮素损失率受施氮量的影响，物种多样性高的牧草具有较强的氮素回收能力。较少

The study of bio-diversity is very important for not only community ecology but also applied ecology. We want to know whether degree of bio-diversity affects efficiency of nitrogen recycling in a pasture or not. Many scientists said that there are close relationship between bio-diversity and production. If there are positive relationships between bio-diversity and production then the ecosystem of high bio-diversity have high ability of maternal recycling such as nitrogen recycling.Then we tried to know the roll of bio-diversity in pasture by two aspects such as effects of management on biodiversity, relation between bio-diversity and nitrogen recycling.Species diversities of plant and soil tick were measured by sampling data from each pasture. Nitrogen losses were calculated by nitrogen amount in milk, fertilizer and feed grains for environmental impact. To measure the efficiency of nitrogen recovery from cattle urine to grass production we used 15N marked urine in another experiment.T … More he plant diversities of low-input pastures of were higher than high-input pastures in some dairy farmers. There is strong relationship between plant and soil tick diversity. Results of Cost-benefit analysis for milk production per unit pasture show the presence of optimal-input for milk production. Many farmers will arrive to optimal point that means high efficiency of milk production. The nitrogen losses were decreased from over 80 % to 50 % during these 20 years.There is a positive relationship between efficiency of milk production per unit pasture and bio-diversity.We estimated the recovery % of nitrogen from cattle urine to grass growth using 15N-marker method ranged 37.37 % to 78.51 %. Therefore nitrogen losses were ranged 20 % to 60 %. About 20 % of nitrogen loss was derived from small amount of urine application. About 60 % of nitrogen loss was derived from large amount of urine application. This result shows the rate of nitrogen loss was affected by amount of nitrogen input.A pasture of high species diversity would have high ability of nitrogen recovery. Less