不同施肥对农田黑土微生物群落的影响

Effect of different fertilizaiton on microbial community in an arable mollisol

以未施肥(CK)和休闲(Fallow)处理为对照,研究黑土肥料定位站NP、NPK、MCK(有机肥)、MNP(有机肥+氮磷)、MNPK(有机肥+氮磷钾)等长期有机、无机肥施用对土壤基本理化性质、磷脂脂肪酸(PLFA)、酸(碱)性磷酸酶、微生物量碳或氮(SMBC或SMBN)等影响。结果表明,有机肥施用有效地提高了土壤有机质、总氮及速效氮、磷、钾等养分含量,显著地增加了SMBC(SMBN)和真菌、细菌的PLFA含量以及磷酸酶活力,极大地提高了土壤真菌/细菌比值;而长期NP或NPK处理不但未明显改善土壤养分状况,甚至抑制了磷酸酶活性及大多数菌群生长。总细菌PLFA与饱和脂肪酸或单烯脂肪酸与环化脂肪酸之间呈极显著正相关(p<0.01)。PLFA主成分分析表明,有机肥与化肥处理微生物群落结构显著不同;个别PLFA载荷值分析表明,真菌脂肪酸易受无机肥施用影响,而G-菌或G+菌脂肪酸更易受有机肥影响。休闲处理高水平微生物活性与生物量的主要贡献者是黑土细菌群落而不是真菌。

The effects of long-term application of NP,NPK,pig manure（MCK）,pig manure plus NP（MNP）and pig manure plus NPK（MNPK）on the microbial communities in a Chinese Mollisol were investigated by the determination of soil basic prosperities,phospholipids fatty acid（PLFA）,acid and alkaline phosphatase activities,and microbial biomass C（SMBC）or N（SMBN）.The nil-fertilizer treatment（CK）and fallow plots were utilized as controls.The results showed that the application of pig manure significantly increased the amounts of soil organic matter（SOM）,total nitrogen（TN）,available phosphorus（AP）,alkali-hydrolysable nitrogen（AN）,and readily available potassium（RAK）.Furthermore,the SMBC or SMBN,ACPase or ALPase activities,fungal or bacterial PLFA contents,and fungal-to-bacterial PLFA ratios in the manure treatments were all higher than those in CK or the chemical fertilizer treatments.Long-term application of NP or NPK had inhibited the two phosphatase activities and the growth of most microorganisms.The relationship between monounsaturated fatty acids（MONO）and cyclopropyl fatty acids（CYCLO）or between normal saturated fatty acids（NSAT）and total bacterial PLFAs was positively correlated at 0.01 levels.PCA of PLFA showed that manure and chemical fertilizers affected microbial community structure in different ways.The loading values for the individual PLFA indicated that fungal 18：2ω6,9 was significantly affected by chemical fertilizers application,while the ones of G-or G＋ were affected by organic manure amendment.The higher levels of microbial activities and biomass in the fallow treatment compared with the other treatments were mainly attributed to soil bacterial groups rather than fungal ones.