施肥与刈割对内蒙古草地生态化学计量特征的影响

Effects of fertilization and mowing on ecological stoichiometric characteristics in an Inner Mongolian steppe

关键词:  氮沉降, 刈割, 碳氮比, 氮磷比

Key words:  nitrogen deposition, mowing, C:N ratio, N:P ratio

摘要:

为明确施肥和刈割对蒙古半干旱草地四种植物化学计量特征的影响,该文于2014年8月以内蒙古半干旱草地的四种植物冷蒿(Artimesia frigida)、菊叶委陵菜(Potentilla tanacetifolia)、羊草(Aneurotepidimu chinense)、扁蓿豆(Melissitus ruthenica)为研究对象,利用方差分析及多重比较分析对照、施氮肥、割草、割草和施氮肥处理下的植物碳、氮、磷含量的差异以及不同处理下碳氮比和氮磷比的变化。结果表明:施氮肥与割草均未影响植物碳含量。施氮肥显著提高了植物氮含量(P<0.05),进而降低了碳氮比(P<0.05),提高了氮磷比(P<0.05)。割草处理后扁蓿豆的氮含量显著提高了0.18%(P<0.05),羊草的氮含量显著降低了0.13%(P<0.05),冷蒿与菊叶委陵菜的氮含量无显著变化。割草显著提高了冷蒿和菊叶委陵菜的磷含量(P<0.05),但是未影响羊草和扁蓿豆的磷含量。该研究证实了氮添加或割草会影响部分草地物种的化学计量特征,但是氮添加或割草对植物化学计量特征的影响存在种间差异。

Abstract:

In order to detect the effects of fertilization and mowing on stoichiometry characteristics of four plant species in an semi-arid steppe in Inner Mongolia. Four plant species including Artemisia frigida, Potentilla tanacetifolia, Aneurotepidimu chinensis, and Melissitus ruthenica in the steppe were collected in August 2014. Contents of carbon, nitrogen and phosphorus, and ratios of C:N and N:P in different plants in field experiment under nitrogen fertilization and mowing treatments were investigated. The effects of nitrogen fertilization and mowing on carbon, nitrogen and phosphorus, and ratios of C:N and N:P were analyzed with ANOVAs. The differences of stoichiometry characteristics under different treatments were analyzed with Post-Hoc tests. The results were as follows: Neither nitrogen fertilization nor mowing altered carbon content in the steppe. Nitrogen fertilization significantly elevated the plant nitrogen content(P<0.05), thus decreased the C:N ratio(P<0.05)and increased the N:P ratio(P<0.05). Mowing increased the nitrogen content of Melissitus ruthenica by 0.18%(P<0.05), decreased the nitrogen content of Aneurotepidimu chinensis by 0.13%(P<0.05), but did not affect the nitrogen content of Aartemisia frigida or Potentilla tanacetifolia. Mowing significantly elevated the phosphorus contents of Artemisia frigida and Potentilla tanacetifolia(P<0.05), but did not affect the phosphorus content of Melissitus ruthenica or Aneruotepidimu chinensis. The study has approved that nitrogen fertilization and mowing can affect the plant stoichiometry characteristics in the steppe, but the affect varied with species. The results provide data support for the study on plant functional traits in the grassland.