湘中丘陵区毛竹林土壤易氧化态碳动态及其影响因素

Dynamics and Influencing Factors of Soil Readily Oxidizable Carbon of Phyllostachy edulis Stands under Different Management Patterns in the Hilly Region of Central Hu'nan,China

研究了湘中丘陵区毛竹笋用林(Ⅰ)、笋材兼用林(Ⅱ)、材用林(Ⅲ)3种不同经营类型林分土壤易氧化态碳(ROC)含量、储量的垂直剖面分布、季节动态及其与土壤总有机碳(SOC)、土壤温度和湿度、土壤养分状况的关系。结果表明:笋用林、笋材兼用林和材用林土壤平均ROC含量分别为2.77 5.15 g·kg-1、2.55 3.67 g·kg-1和3.21 5.36 g·kg-1,ROC储量分别为17.19 32.52 t·hm-2、17.29 24.60 t·hm-2和19.04 31.85 t·hm-2;在垂直分布上,不同类型毛竹林ROC含量、储量随土壤深度增加而下降,0 20 cm土层是ROC的主要分布区;在季节动态上,4月ROC含量、储量均明显低于其它季节;ROC与土壤温度、湿度负相关不显著;ROC与SOC、有机质、全氮和速效钾之间具有显著正相关性。

Based on plot data of shoot utilizing （ I ）, shoot and timber utilizing （ 11 ） and timber utilizing （ 111 ） stands of PhyUostachy edulis located at the hilly region in central Hu＇ nan Province, a research was carried out on the vertical distribution and seasonal dynamics of soil readily oxidizable carbon （ROC） and its relationship with soil total organic carbon （ SOC）, soil temperature, soil humidity and soil nutrients under the three types of management pattern. The results showed that the average ROC concentrations of type I, II and III were 2.77 -5.15 g -2 kg-2, 2.55 -3.67 g · kg-1 and 3.21 -5.36 g ·kg-1, and the ROC storages were 17.19 -32.52 t· hm-2, 17.29 - 24.60 t ·hm-2 and 19.04 -31.85 t · hm-2 respectively. The vertical distribution showed that the ROC concentrations and storages decreased with the increase of soil depth in the three stands. Moreover, the soil layer of 0 -20 cm was the main distribution layer of SOC. For seasonal dynamics, the ROC concentrations and storages in April were obvious lower than that in other seasons. The ROC was negatively related with the soil temperature and humidity slightly that showed ROC decomposition and mineralization accelerating. The ROC was significantly positively relat- ed with the SOC, the organic matter, the total N and the available K.