三峡库区澎溪河消落带落干期土壤硝化强度及影响因素

研究了三峡库区澎溪河落干期消落带不同地点、不同高程段、不同土地利用方式下土壤硝化强度及影响因素。结果表明,研究区域消落带硝化强度范围为0.76~9.76 mg/kg·d,平均值为3.76±0.76mg/kg·d,明显低于国内其他研究区域土壤硝化强度。澎溪河消落带从上游汉丰湖到下游黄石,土壤硝化强度呈现递减的趋势。随着高程的增加,消落带土壤硝化强度逐渐降低,但没有显著差异(P0.05)。消落带不同土地利用方式中,河滩地土壤硝化强度显著高于耕地土壤硝化强度(P0.05),是耕地土壤硝化强度的1.82倍。消落带土壤硝化强度与土壤pH值呈显著正相关(P0.05),与有机质含量及亚硝化菌数量呈极显著正相关(P0.01),周期性的淹水影响了消落带土壤pH值和有机质含量,从而影响了消落带土壤硝化强度。

Nitrification intensity in soils and its impact factors of Pengxi WLFZ in Three Gorges Reservoir area during the dry period

The impacts of land locations, utilization patterns and elevations on soil nitrification intensity in Pengxi water-level-fluctuating zone (WLFZ) during the dry period in the Three Gorges Reservoir area were studied. The results indicate that the nitrification intensity of the WLFZ soil ranges from 0.76 mg/kg·d to 9.76 mg/kg·d, while the intensity averages at (3.76±0.76) mg/kg·d, which is significantly lower than those reported in other domestic researches. The soil nitrification intensity decreases from upstream (Hanfeng lake) to downstream (Huangshi city). In addition, the increase of elevation weakly decreases the nitrification intensity (P >0.05). Moreover, the nitrification intensities of flood lands are 1.82 times of those of cultivated soils (P<0.05). The soil nitrification intensity is significantly positively correlated with the soil pH value(P<0.05) as well as the contents of organic matter and the number of nitrosobacteria (P<0.01). Periodic flooding affects the soil pH and organic matter contents, which leads to the variation of soil nitrification intensity.