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作 者 ：杨贤燕¹;蒋琦清¹;唐建军¹;陈欣¹;Hu Shuijin²

期 刊 ：应用生态学报 2007年 18卷 04期 页码：848-852

关键词：稗；

摘 要 ：在昼/夜温度为35 ℃/25 ℃和30 ℃/20 ℃条件下，研究了模拟氮沉降对稗草和陆稻生长及竞争关系的影响.结果表明：35 ℃/25 ℃条件下,每年输入4 g·m^-2氮处理,稗草和陆稻地上部分生物量分别比对照增加29.18%和27.80％,稗草吸收氮和磷量分别增加87.33%和49.73%,而陆稻吸收氮和磷量无显著变化.在30 ℃/20 ℃条件下,每年输入2、4、6 g·m^-2氮处理后,稗草地上部分生物量分别比对照增加48.99％、72.68％和36.18％,分蘖数分别增加111.11％、122.22％和144.44％,稗草植株氮和磷吸收量分别增加108.88％、129.22%、134.29％和16.53％、65.05%、22.47%,而陆稻均无显著变化.在30 ℃/20 ℃条件下,氮沉降显著增加了稗草与陆稻地上部分生物量的比值,但在35 ℃/25 ℃条件下影响不显著.表明氮沉降增加可能会提高稗草而降低陆稻的竞争力,而且在温度较低的情况下，这种趋势更明显.

Abstract:A greenhouse experiment was conducted to study the effects of simulated nitrogen deposition on the growth and competition of C₄ weedy species (Echinochloa crusgalli var. mitis L.) and C₃ upland rice (Oryza sativa L.) under day/night temperature of 35 ℃/25 ℃ and 30 ℃/20 ℃. The results showed that under day/night temperature 35 ℃/25 ℃, 4.0 g·m^-2·a^-1 N deposition enhanced the shoot biomass of E. crusgalli and O. sativa by 29.18% and 27.80%, respectively, compared with control. The N and P uptake by E. crusgalli increased by 87.33% and 49.73%, respectively, but no change was found for O. sativa. Under 30 ℃/20 ℃, three N depositions (2, 4 and 6 g·m^-1 ·a^-1) enhanced the shoot biomass, tiller number, and shoot N and P uptake of E. crusgalli by 48.99%, 72.68% and 36.18%, 111.11%, 122.22% and 144.44%, 108.88%, 129.22% and 134.29%, and 16.53%, 65.05% and 22.47%, respectively, but no changes were observed for O. sativa. Nitrogen deposition significantly increased the shoot biomass ratio of E. crusgalli to O. sativa under 30 ℃/20 ℃, but had no impact on this ratio under 35 ℃/25 ℃. It was suggested that N deposition could enhance the competition of E. crusgalli over O. sativa, especially under lower air temperature.

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