黄土丘陵区不同施肥处理对土壤微生物特性的影响

Effects of long-term fertilization on soil microbial properties in the Loess hilly-gully region,China

研究旨在探讨在土壤贫瘠的黄土丘陵区,施肥对土壤微生物产生的影响及其机理。试验以安塞站内长期定位施肥小区为研究对象,试验处理包括CK(对照)、N(氮肥)、P(磷肥)、M(有机肥)、NP(氮肥+磷肥)、MN(有机肥+氮肥)、MP(有机肥+磷肥)和MNP(有机肥+氮肥+磷肥),研究长期施肥对土壤微生物群落结构和呼吸的影响。0—20cm耕作层的土壤微生物活性和PLFA含量均高于20—40cm土层的微生物活性和PLFA含量,耕作层较20—40cm基础呼吸提高63.61%—116.78%,诱导呼吸提高53.45%—137.64%,总PLFA含量提高16.16%—43.67%。单施N和P增强了土壤呼吸强度,0—20cm基础呼吸强度分别升高34.11%和48.89%,诱导呼吸强度分别升高40.83%和63.59%,20—40cm基础呼吸分别升高40.83%和63.59%,诱导呼吸分别升高14.70%和20.49%。单施N显著改变G-微生物群落,0—20cm和20—40cm土层的PLFA含量分别显著升高63.19%和53.07%,单施P对土壤微生物群落结构同样产生显著影响,但是NP对微生物群落结构的影响不显著。有机无机肥配施显著提高土壤呼吸及微生物PLFA含量。通过三因素方差分析,单一氮肥因素对土壤微生物特性的影响不显著;单一磷肥因素对微生物的呼吸强度及部分磷脂脂肪酸含量产生显著影响,在耕作层中,磷肥因素对这些微生物特性的影响比率为11.4%—54.0%。通过RDA分析,表明土壤速效磷是影响黄土丘陵区微生物特性的主要因素。长期氮磷有机肥混施有助于提高土壤微生物的特性,进而改善农田生态系统的稳定和健康水平。

The experiment was set up to investigate the effects of fertilization on soil microbial properties and its mechanism in the Loess Hilly Region. Soil microbial community structure and respiration under long-term fertilizations,including CK(control）,N(nitrogen fertilizer）,P(phosphorus fertilizer）,M(manure）,NP(nitrogen fertilizer ＋ phosphorus fertilizer）,MN(manure ＋ nitrogen fertilizer）,MP(manure ＋ phosphorus fertilizer） and MNP(manure ＋ nitrogen fertilizer ＋ phosphorus fertilizer）,were studied at Ansai Field Research Station. The results showed that microbial activities and PLFA contents in surface soil(0—20 cm） were higher than those in the sub soil(20—40 cm）; Basal respiration,substrate-induced respiration and total PLFA contents in surface soil were 63. 61% —116. 78%,53. 45% —53. 45% and16.16% — 43. 67% higher than those in sub soil. Compared to the CK treatment,N fertilizer and P fertilizer increased surface soil basal respiration by 34.11% and 48.89%,respectively,and substrate-induced respiration intensities increased by 40.83% and 63.59%; In sub soil,the basal respiration intensities increased by 40.83% and 63.59%,and the substrateinduced respiration intensities increased by 14. 70% and 20. 49%,respectively. The effect of N fertilizer on G-microbial community was significant and increased PLFA contents in 0—20 cm and 20—40 cm soil profile significantly by 63.19% and53.07%. And P fertilizer also altered the microbial community structure significantly,however,the effects of the mixed fertilizer of NP on microbial community structure was not significant. The mixture of organic and inorganic fertilizers had a significant influence on soil respiration and microbial community structure. Variance analysis of three factors indicated that the effects of single N fertilizer factor on soil microbial properties were not significant; single N fertilizer had significant effect on the microbial respiration and PLFA contents. In the 0—20 cm soil layer,the ratio of P fertilizer factor influencing these microbial characteristics was 11. 4% —54. 0%. The RDA analysis indicated that available P played a major role in driving the change in microbial characteristics. Long-term mixed manure,N and P fertilizers could improve soil microbial properties,thus contribute to the stability and sustainability of farmland ecosystem.