不同施肥模式对杨树人工林土壤微生物生物量C、N、P的影响

以江苏东台林场5年生杨树人工林为对象,在2012年6月设置了不同施肥处理(N、P、K复合肥,T1; 有机肥,T2; 生物炭,T3; N、P、K复合肥+生物炭,T4; 有机肥+生物炭,T5; 对照,CK),并在2012年8月至2013年6月期间每2个月1次共进行6次重复土壤取样,研究了不同施肥模式对土壤微生物生物量C、N、P(SMBC、SMBN、SMBP)的影响。结果显示:①5种施肥模式均显著提高了SMBC和SMBN,但对SMBP的影响较小,仅T1处理与对照间达到显著性差异; ②在0～10 cm土层仅T5处理显著降低了SMBC与SMBN的比值,在≥10～25 cm土层各处理SMBC与SMBN的比值均未显著下降,而在≥25～40 cm土层T1、T2、T4和T5处理的SMBC与SMBN的比值均显著下降,表明不同施肥模式对土壤N供应能力的改善作用随土层深度的增加而增加。综合分析表明,T4处理最有利于提高杨树人工林SMBC、SMBN和SMBP的含量,同时有利于提高土壤对植物生长所需有效N的供给,因此T4处理即N、P、K复合肥+生物炭可作为该区域杨树人工林的最佳施肥模式。

Effects of different fertilization regimes on soil microbial biomass C,N, P under poplar plantation

In order to learn the effects of different fertilization regimes on soil microbial biomass C, N, P under poplar plantations, six different treatments(NPK compound fertilizer, T1; organic fertilizer, T2; biochar, T3; NPK compound fertilizer + biochar, T4; organic fertilizer + biochar, T5; control treatment, CK)were set up under the poplar plantation of 5 years old in Dongtai Forest Centre of Jiangsu Province. The fertilization treatments were completed in June 2012, and the soil samples from different sites were collected every two months during August 2012 to June 2013. The results showed that: Five different fertilization regimes significantly improved soil microbial biomass C and N content in three different soil layers, but exerted less effect on soil microbial biomass P, only T1 treatment significantly increased soil microbial biomass P content in three different soil layers, and T4 treatment significantly increased soil microbial biomass P content in 0-10 cm soil layer compared with control treatment. T2, T4 and T5 treatments tended to reduce soil microbial biomass C/N ratio in 0-10 cm and ≥10-25 cm soil layer, but only T5 treatment significantly reduced it in 0-10 cm soil layer comparing with CK. However, T1, T2, T4 and T5 treatments significantly reduced soil microbial biomass C/N ratio in ≥25-40 cm soil layer, suggesting that the improvement effect of different fertilization regimes on supply capacity and plant availability of soil N increased with the increase of soil depth. T4 treatment performed best in increasing soil microbial biomass C, N, P of poplar plantation, at the same time, can improve supply capacity and plant availability of soil N, therefore it was the optimal fertilization regime.