水热条件和土壤类型对纤维素分解菌的影响

试验选择中国东部3个气候带上的主要农田土壤:寒温带黑龙江海伦的黏化湿润均腐土(黑土)、暖温带河南封丘的淡色潮润雏形土(潮土)和中亚热带江西鹰潭的黏化湿润富铁土(红壤),在海伦、封丘和鹰潭3个生态试验站建立土壤置换试验,研究玉米不同生育期水热条件和土壤类型对好氧性纤维素分解菌数量的影响。结果表明,暖温带气候条件下土壤好氧性纤维素分解菌数量高于中温带和中亚热带气候条件;土壤类型显著影响了土壤好氧性纤维素分解菌数量,变化顺序为黑土>潮土>红壤;在玉米不同生育期土壤纤维素分解菌数量的顺序均为抽雄期>收获后>种植前;施用化肥提高了土壤中好氧性纤维素分解菌的数量。相关分析显示土壤好氧性纤维素分解菌数量与土壤有机质、全氮、全磷、全钾、含水量和pH值呈显著正相关,土壤温度和含水量是影响土壤好氧性纤维素分解菌数量的重要环境因子。通径分析结果表明,土壤养分是决定土壤好氧性纤维素分解菌数量的主要因子,水热条件对其直接作用并不明显,但水热、施肥、土壤类型对纤维素分解菌数量有显著的交互作用。

Effects of climate conditions and soil type on aerobic cellulose degrading bacteria

Effects and interactions of temperature-rainfall, soil type and feitilizaiton on soil aerobic cellulose degrading bacteria (ACDB) number during the different growth periods of corn were studied by a soil reciprocal transplantation experiment installed in 3 experiment stations of Chinese Ecological Research Network, i.e. Hailun, Fenqiu and Yingtan Agro-ecological Experiment Station, which represented cold temperate, warm temperate and middle subtropical zone, respectively. Three types of cropland soils were selected, i.e. neutral black soil (Phaeozem), alkaline Chao soil (Cambisol) and acidic red soil (Acrisol). Then one-meter depth soil profiles for each soil were transplanted in 3 stations to build the field experiment. The results showed that the number of soil ACDB under warm temperate zone was higher than cold temperate and subtropical zones. Soil type controlled the change of ACDB, the total number of ACDB was highest in black soil, followed by chao soil and red soil. All treatments followed the same trend among the different corn growth periods with the highest number in corn vigorous growth period and least before corn planted. Fertilization could increase soil ACDB significantly. Statistical analysis revealed there was a significant positive correlation between the total number of soil ACDB and soil organic matter, total N, total P, total K, and soil pH (P<0.05), soil temperature and water content were major environmental factors influencing the number of ACDB, but soil nutrient contents instead of climate conditions have critical effects on the activities of ACDB. There were significant interactions of climate, soil type and fertilization on the change of soil ACDB.