| 模拟放牧斑块与氮素添加对半干旱草原群落植物生长的影响 |
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| 引用本文： | 袁志友,李凌浩,韩兴国,姜凤河,林国辉,赵明旭,任丽昀. 模拟放牧斑块与氮素添加对半干旱草原群落植物生长的影响[J]. 植物学报(英文版), 2004, 46(9): 1032-1039 |
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| 作者姓名： | 袁志友 李凌浩 韩兴国 姜凤河 林国辉 赵明旭 任丽昀 |
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| 基金项目： | 中国科学院知识创新工程项目，国家重点基础研究发展计划(973计划) |
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| 摘 要： | 放牧时,动物采食及其排泄物会影响植物的生长,但动物彩食及其排泄物的空间异质性可能会影响这咱效应.在位于我国北方典型农牧交错区的内蒙古多伦县,我们研究了模拟入牧斑块和施氧肥对植物生长的影响,实验采用模拟放牧采食斑块(观割半径分别0、10、20、40和8cm)和土壤施氮(分别为0、5、20Gnm2)两种处理,植物地上部收获后分为绿体和立柯两部分,并分析其含氮量.结果表明,刈割降低了植物的生物量(40.5%),而施氮可增加生物量(57.8%)刈割交通规则植物生长的抑制作用在面积最水又施肥的斑块上表现更明显.土壤施氮可以促进杜物生长并且影响刈割效应.同时植物的绿-枯比阻碍施氮水平的增回而增回,因此氮会延迟植物的衰老.以上结果表明,刈割(模拟动物采食)斑块的大小会影响草原植物的生长,土壤施氮(模拟动物尿氮)可以提高草原生态系统的初级生产力,并影响刈割效应.
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| 关 键 词： | 模拟放牧采食 氮素食物 氮素添加:放牧斑块 相对生长速率 |
Effects of Simulated Grazing Pattern and Nitrogen Supply on Plant Growth in a Semiarid Region of Northern China |
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| YUAN Zhi-You,LI Ling-Hao,HAN Xing-Guo,JIANG Feng-He,LIN Guo-Hui,ZHAO Ming-Xu,REN Li-Yun. Effects of Simulated Grazing Pattern and Nitrogen Supply on Plant Growth in a Semiarid Region of Northern China[J]. Journal of integrative plant biology, 2004, 46(9): 1032-1039 |
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| Authors: | YUAN Zhi-You LI Ling-Hao HAN Xing-Guo JIANG Feng-He LIN Guo-Hui ZHAO Ming-Xu REN Li-Yun |
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| Abstract: | Grazing in grassland ecosystems affects plant growth by removing biomass and depositing excretal nutrients. However, grazing is not uniformly distributed in space. The spatial pattern of defoliation and excretion deposition by herbivores across vegetation mosaics has been frequently discussed, but rarely spatially quantified. A 60-day field experiment in a native semiarid grassland community was conducted to examine the responses of plant growth to simulated grazing pattern and varying nitrogen levels. Plants were subjected to five defoliation treatments determined by circularly clipped patches of different size (0, 10, 20, 40, 80 cm in radius), and four nitrogen supply levels in soils (0, 5, 10, 20 g N/m2). It was detected that defoliation had reduced primary productivity by 41.5% whereas fertilization had increased it by 57.8%. The negative effect of defoliation was greater in the smallest, fertilized patches. N addition had been found to have altered the effect of defoliation, as plants growing at higher nitrogen levels were more negatively affected by defoliation than plants with no supplementary application of nitrogen. These results indicated that the magnitude of defoliation response for an individual plant was modulated by not only defoliation itself, but also other factors, such as nutrient availability. The increase in the ratio of live to dead plant parts suggested that urine deposition delayed the senescence of plants. The results also showed that (1) the effect of defoliation on primary productivity was affected by the patch size, and (2) nitrogen addition (simulated urine deposition) could increase primary productivity and affect the response to defoliation more obviously in the smaller patches than in the larger ones. |
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| Keywords: | simulated defoliation nitrogen fertilization grazing patch relative growth rate |
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