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三江平原是我国最大的沼泽化低平原,同时也是受人类活动影响最剧烈的区域之一。选取三江平原两类典型湿地-常年积水的毛果苔草(Carex lasiocapa)沼泽和季节性积水的小叶章(Deyeuxia angustifolia)草甸及由其垦殖的水田和旱田为研究对象,利用静态暗箱-气相色谱法对土壤呼吸速率进行了观测。研究结果表明,小叶章草甸与毛果苔草沼泽土壤呼吸速率的季节变化形式相同,为单峰型,在夏季出现排放峰值,而冬季呼吸速率最低。沼泽湿地垦殖为旱田后,土壤呼吸速率的季节变化形式未发生变化,但垦殖为水田后,土壤呼吸速率排放峰值的时间延后在秋季出现。毛果苔草沼泽、小叶章草甸、旱田及水田通过土壤呼吸释放的碳量分别为(3.1±0.4)、(4.8±0.7)、(2.8±0.4)、(2.2±0.3)tC.hm-2.a-1。毛果苔草沼泽土壤呼吸速率低于小叶章草甸是由沼泽湿地的积水环境差异造成的,而沼泽湿地垦殖为农田后土壤呼吸作用减弱,主要是由于垦殖后土壤有机碳含量大幅降低所致。相关分析表明,温度和土壤湿度(或积水深度)是影响土壤呼吸速率的重要因素,温度与小叶章草甸、毛果苔草沼泽以及旱田土壤呼吸速率呈显著指数关系,Q10值分别为2.1、2.5和1.8,沼泽湿地垦殖为旱田后温度敏感性指数降低,主要是由于土壤微生物营养源减少从而对微生物营养供应受限造成的。小叶章草甸、毛果苔草沼泽、旱田以及水田土壤呼吸速率与土壤湿度/积水深度之间的关系可用线性或二次曲线方程来描述。
The Sanjiang Plain is one of the largest swampy plains in our country and one of the most affected by human activities. Two typical wetlands, the Carex lasiocapa swamp and the seasonal watery Deyeuxia angustifolia meadow, and the reclaimed paddy fields and paddy fields from two typical wetlands in the Sanjiang Plain were selected as research objects. Static dark box-gas phase The soil respiration rate was observed by chromatography. The results showed that the seasonal variation of soil respiration rate was the same as that of Populus simonii and Carex lasiocarpa, with a unimodal pattern, with peak emission in summer and lowest in winter. After the reclamation of swamp wetland into dry farmland, the seasonal variation of soil respiration rate did not change, but after the cultivation of paddy field, the peak of soil respiration rate was delayed in autumn. The amount of carbon released by soil respiration through Carex lasiocarpa, Betula platyphylla, upland and paddy fields were (3.1 ± 0.4), (4.8 ± 0.7), (2.8 ± 0.4) and (2.2 ± 0.3) tC.hm-2, respectively. a-1. The soil respiration rate of Carex lasiocarpa is lower than that of Betula platyphylla, which is caused by the difference of water environment of marsh wetlands. However, the respiration of marshland after farmland cultivation is weakened, mainly due to the significant decrease of soil organic carbon after cultivation. Correlation analysis showed that temperature and soil moisture (or depth of water) were the important factors affecting soil respiration rate. The temperature had a significant exponential relationship with soil respiration rate of Betula platyphylla, Carex lasiocarpa and dryland, and the Q10 values were 2.1, 2.5 And 1.8, the temperature sensitivity index decreased after the marsh was reclaimed from the dry land, which was mainly caused by the limited supply of nutrients to the microorganism due to the decrease of the nutrient source of the soil microorganism. The relationship between soil respiration rate and soil moisture / depth of water in the meadow, meadow moss, mulberry grass, paddy fields and paddy fields can be described by a linear or quadratic curve equation.