几种改良措施对酸化茶园土壤理化性质和微生物群落结构的影响

茶园土壤酸化是制约茶树可持续生产的重要因素,通过田间小区试验分析比较几种措施对茶园土壤的改良效果,以期为茶园酸化土壤改良提供科学依据。试验设置7个处理：全量化肥（常规施肥,NPK）、全量化肥+10 t?hm^-2生物质炭（NPK+BC10）、有机肥替代50%化肥（OM50）、有机肥替代50%化肥+2 t?hm^-2生石灰（OM50+Lime）、有机肥替代50%化肥+10 t?hm^-2生物质炭（OM50+BC10）、有机肥替代50%化肥+20 t?hm^-2生物质炭（OM50+BC20）、有机肥替代50%化肥+40 t?hm^-2生物质炭（OM50+BC40）。连续施用2年后,对茶园土壤酸度、养分和微生物群落进行测定。与NPK相比,OM50+Lime、OM50+BC20和OM50+BC40处理土壤pH分别显著提高1.10、0.49和0.68,盐基饱和度分别显著提高114.01%、55.92%和58.62%。OM50+BC10、OM50+BC20和OM50+BC40处理的土壤有机碳含量分别比NPK处理显著增加了29.68%、41.04%和59.37%。不同处理对土壤硝态氮含量无显著影响,OM50、OM50+BC20和OM50+BC40处理的铵态氮含量比NPK处理分别显著提高了40.27%、44.77%和41.77%。NPK+BC10、OM50+BC10、OM50+BC20和OM50+BC40处理能显著提高土壤微生物活性、微生物群落物种丰富度、多样性和均一性。OM50+BC10、OM50+BC20和OM50+BC40处理显著降低了真菌/细菌比例,表明这3个处理短期内增加了红壤茶园土壤生态系统稳定性,但OM50+Lime处理的革兰氏阴性菌/革兰氏阳性菌比例显著低于对照处理,表明施用生石灰处理的土壤微生物受到的环境胁迫程度高于其他处理。总之,OM50+Lime、OM50+BC20和OM50+BC40处理对酸化茶园土壤有较好的改良效果,OM50+BC20和OM50+BC40处理对土壤微生物群落性质方面的改良效果更佳。综合考虑改良效应及成本,OM50+BC20为最佳改良方案。

Ameliorative Effect of Several Measures on Soil Physicochemical Properties and Microbial Community Structures in Acidified Tea Gardens

Acidification of tea garden soil is an important factor that restricts sustainable production of tea plants. Field plot experiments were conducted to study the effects of several improvement measures on acidified tea soils, which would provide scientific basis to improve the soil quality. The experiment involved several treatments: (1) pure chemical fertilizer (routine fertilization, NPK), (2) chemical fertilizer plus 10 t?hm^-2 biochar (NPK+BC10), (3) organic manure substituted 50% of chemical fertilizer (OM50), (4) organic manure substituted 50% of chemical fertilizer plus lime (OM50+Lime), (5) organic manure substituted 50% of chemical fertilizer plus 10 t?hm^-2 biochar (OM50+BC10), (6) organic manure substituted 50% of chemical fertilizer plus 20 t?hm^-2 biochar (OM50+BC20), and (7) organic manure substituted 50% of chemical fertilizer plus 40 t?hm^-2 biochar (OM50+BC40). After two years of continuous application, soil samples were taken to determine the soil acidity, the nutrient contents, and the microbial community. The microbial community structure was measured using phospholipid fatty acid (PLFA) and Biolog technology. Compared with NPK, soil pH were significantly increased by 1.10, 0.49 and 0.68 units, and base saturation were significantly increased by 114.01%, 55.92% and 58.62% in OM50+Lime, OM50+BC20, and OM50+BC40 treatments, respectively. Compared with NPK, soil organic carbon contents under OM50+BC10, OM50+BC20 and OM50+BC40 treatments were significantly increased by 29.68%, 41.04% and 59.37%, respectively. All treatments had no significant effect on soil nitrate nitrogen content, while the ammonium nitrogen contents under OM50, OM50+BC20 and OM50+BC40 treatments were significantly increased by 40.27%, 44.77% and 41.77% compared with NPK. NPK+BC10, OM50+BC10, OM50+BC20 and OM50+BC40 significantly increased soil microbial activity, species richness, diversity and homogeneity of microbial community. OM50+BC10, OM50+BC20 and OM50+BC40 treatments significantly reduced the ratios of fungi to bacteria, indicating that they increased the stability of soil ecosystem in the short term. The ratio of gram-negative bacteria to gram-positive bacteria under OM50+Lime treatment was significantly lower than that under NPK, which indicates that soil microorganism under OM50+Lime suffered the greater environmental stress than that under other treatments. In summary, OM50+Lime, OM50+BC20 and OM50+BC40 had obvious improvement effect on acidified tea garden soil, while OM50+BC20 and OM50+BC40 had better improvement effect on soil microbial community properties than OM50+Lime. Simultaneous considering ameliorative effect and cost of economy, OM50+BC20 was the best improvement scheme.