【作者】 崔骁勇； 陈佐忠；

【Author】 Cui Xiaoyong Chen Zuozhong (institute of Botany, Chinese Academy of Sciences, Beijing 100093)

【机构】 中国科学院植物研究所；

【摘要】 在内蒙古半干旱草原区对羊草群落补充N、P、K等矿质营养元素,肥料在生长盛期开始时随雨水施用,一个月后施氮量30kg/hm²处理的群落生物量与对照相当,而施肥量为60和90kg/hm²处理的群落生物量显著高于对照处理,磷、钾单独施用或者配合施用氮肥短期内对羊草群落的生产力没有明显作用。不同植物类群对矿质元素添加的反应不同,30kg/hm²的氮肥对各类群的影响都不显著,氮肥施用量在60kg/hm²时羊草生物量受到显著促进,氮肥用量再增加后羊草的生物量不再提高。在N₂的基础上施用磷肥羊草、其他禾草以及豆科植物的生长都受到一定程度的刺激。施肥后群落对土壤氮素的吸收量基本与群落最大生物量正相关,秋冬季土壤氮素矿化量以PK、N₁、N₂、N₃PK处理较高,氮的淋失量与总矿化量有一定的正相关关系。施用氮磷肥后促进了土壤磷素的矿化,而对硫的影响不大。研究表明,矿质元素添加对草原生态系统土壤和植物都有较大的影响,营养元素种类和植物类群之间的存在复杂的关系,这预示着半干旱草原生态系统的结构和功能在全球变化导致的气候变暖过程中可能发生较大改变。更多还原

【Abstract】 Different amount of N, P, and K was applied to Leymus chinensis community in semiarid steppe in Inner Mongolia. The fertilizers were top-dressed with rain at the early stage of community fast growing. After about one month, standing crop of control and 30kg/hm2did not differ significantly while higher rate of nitrogen stimulated productivity obviously. P and K had on marked effect on community biomass by either applied singly or with nitrogen.Treatment of 30kg/hm2nitrogen had not significant effect on all plant types.Biomass of Leymus dunensis greatly increased under 60kg nitrogen treatment.However, further elevation of nitrogen amount did not cause additional growth increment of different plant forms. Leymus dunensis, other graminoid species, and legume species were prominently promoted under P supplying with 60kg/ hm2 nitrogen. Amount of nitrogen absorbed by plants correlated positively with maximal community biomass.Leaching of nirtogen was positively affected by mineralized soil nitrogen quantity, which was much higher in treatment PK, N1, N2, andN3PK. Applying of N and P increased soil P mineralization but not soil S.The results suggested that enrichment of soil mineral nutrients had proround influence on grassland ecosystem for both plants and soil.There was complicate interaction between nutrient type and plant species.lt was prospected that climate warming induced by global change would significantly modify the structure and function of semiarid steppe ecosystem.更多还原