小兴安岭小叶章根际微生态系统土壤碳空间分布特征

根际微生态系统包括土壤、植物根系和土壤微生物三大部分,它是联接大气、水体、土体、生物体碳流通的中间环节,是生态系统碳循环的关键部分。揭示小叶章根际微生态系统碳的时空动态对于研究小叶章生态系统碳循环具有重要意义。碳素是生命有机体的关键组成成分,根际微生态系统是物质循环的核心区域。论述了根际微生态系统的概念和内涵及其中间环节,是生态系统碳循环的关键部分。研究了国内外近年来根际微生态系统土壤有机碳(SOC)空间分布特征。分别描述了柱状实验和小室实验各类土壤的SOC含量。柱状实验和小室实验的结果显示了较好的一致性;在整个生长季节内,根层根际土和根层根表土SOC含量最高,表层根际土和下层根际土SOC含量相对较高,表层非根际土和下层非根际土SOC含量最低;且保持稳定。并且描述了柱状实验和小室实验各类土壤的土壤微生物量碳(MBC)含量。MBC的空间分布同样也包括为垂直分布和水平分布,垂直分布表现为MBC浓度的差异和微生物活性的差异,主要原因为根系在垂直方向上的不同生长特性导致不同的根系沉积,进而引起的微生物活性差异;水平分布主要由土壤微生物自身水平移动或在其它介质作用下的水平迁移所导致MBC在水平方向上浓度差异。

土壤微生态系统中聚丙烯微塑料对土壤酶活性的影响

微塑料污染作为一种新型的环境问题,已经对人们的生活构成了极大的威胁。微塑料虽然对土壤性质、土壤动植物产生影响,干扰土壤生态系统,但是针对微塑料对土壤生态系统的影响研究仍较少。笔者研究了蚯蚓和大豆存在的土壤微生态系统中微塑料聚丙烯对土壤脱氢酶、蔗糖酶和脲酶活性的影响。研究结果表明:聚丙烯微塑料的存在会抑制土壤脱氢酶、蔗糖酶活性,促进土壤脲酶活性;蚯蚓能够改善聚丙烯微塑料对土壤脱氢酶的抑制作用;低质量分数聚丙烯微塑料能提高土壤蔗糖酶活性,高质量分数则表现为抑制作用。大豆的生长能够显著促进土壤蔗糖酶活性;高质量分数聚丙烯微塑料通过影响蚯蚓、大豆的生命活动和生长发育间接影响土壤脲酶活性。

土壤微生态系统中3,6-二氯咔唑对土壤酶活性的影响

卤代咔唑作为一类新型有机污染物,给人类的健康和生态环境带来了潜在的危险。研究卤代咔唑对土壤中动物、植物和微生物的影响,具有较好的现实意义。研究了在蚯蚓和大豆同时存在的土壤生态系统中,3,6-二氯咔唑(3,6-CCZ)对土壤脱氢酶、脲酶和蔗糖酶活性的影响。实验结果表明:低浓度和高浓度实验组较空白组,土壤脱氢酶活性上升了76.5%和29%,土壤脲酶活性上升了7.4%和39.4%,土壤蔗糖酶活性上升了50%和下降了2.7%,表明3,6-CCZ对土壤酶活性有增强作用,蚯蚓的引入能够显著增强土壤酶活性,大豆的种植虽然没有表现出明显的促进或抑制作用,但是在一定程度上缓解了3,6-CCZ和蚯蚓的增强作用;蚯蚓和大豆同时存在,并不能有效缓解3,6-CCZ对土壤酶活性的作用。

酵素微生物套餐肥对桃园果实品质及土壤微生态的影响

本课题以传统施肥为对照,通过大田试验研究了酵素微生物套餐肥对‘龙峰桃’品质及桃园土壤微生态的影响。结果表明,采用酵素微生物套餐肥种植的‘龙峰桃’油桃品种比传统施肥种植的油桃感官、营养物质及安全性均得到提高;酵素微生物套餐肥有助于提高土壤营养物质,其中有机质含量、铵态氮、速效磷、速效钾较对照分别增加129%、9.6%、38.3%、54%;此外,酵素微生物套餐肥还有助于土壤中活菌数量及代谢活动的增加,可使细菌数量提高61.9%、放线菌数量提高39.3%、总菌量提高61.1%。

Machine learning models reveal how biochar amendment affects soil microbial communities

The biochar amendment plays a vital role in maintaining soil health largely due to its effects on soil microbial communities.However,individual cases and the variability in biochar properties are not sufficient to draw universal conclusions.The present study aimed to reveal how the biochar application affects soil microbial communities.Metadata of 525 ITS and 128816S rRNA sequencing samples from previous studies were reanalyzed and machine learning models were applied to explore the dynamics of soil microbial communities under biochar amendment.The results showed that biochar considerably changed the soil bacterial and fungal community composition and enhanced the relative abundances of Acidobacteriota,Firmicutes,Basidiomycota,and Mortierellomycota.Biochar enhanced the robustness of the soil microbial community but decreased the interactions between fungi and bacteria.The random forest model combined with tenfold cross-validation were used to predict biomarkers of biochar response,indicating that potentially beneficial microbes,such as Gemmatimonadetes,Microtrichales,Candidatus_Kaiserbacteria,and Pyrinomonadales,were enriched in the soil with biochar amendment,which promoted plant growth and soil nutrient cycling.In addition,the biochar amendment enhanced the ability of bacteria to biosynthesize and led to an increase in fungal nutrient patterns,resulting in an increase in the abundance and diversity of saprophytic fungi that enhance soil nutrient cycling.The machine learning model more accurately revealed how biochar affected soil microbial community than previous independent studies.Our study provides a basis for guiding the reasonable use of biochar in agricultural soil and minimizing its negative effects on soil microecosystem.