指数施肥对杉木苗期基质中微生物功能多样性的影响

为向轻型基质容器苗合理施肥,实现苗木养分精准调控提供理论依据,以杉木优良无性系"洋061"轻型基质容器苗为研究对象,设置7个施氮处理[对照(CK,0 mg/株)、常规集中施肥处理(CF1,40 mg/株)、常规分次施肥处理(CF,240 mg/株)、指数施肥(EF1,40 mg/株;EF2,80 mg/株;EF3,12...

Effects of nitrogen fertilization on microbial functional diversity in a light-medium for Cunninghamia lanceolata(Lamb.) Hook seedlings

The present study investigated the effects of different nitrogen treatments on microbial diversity and carbon utilization characteristics in a light-medium, revealing the response characteristics and thus providing a theoretical basis for accurate nutrient management and a rationale for fertilization of light-medium seedlings. An exponential fertilization(EF) experiment with five nitrogen dose levels(0, 40, 80, 120, and 160 mg/plant) combined with conventional fertilization(CF) with a nitrogen level of 40 mg/plant was conducted using seedlings from cuttings of the superior clone of Cunninghamia lanceolata "Yang 061". Additionally, Biolog ECO-plate methods were employed to analyze the soil microbial diversity and metabolic activity of light-medium seedling soils under the various fertilization treatments. The results showed that the metabolic activity of soil microbes was enhanced under different fertilization treatments, and decreased in the following order: EF2 > EF3 > EF1 > CF2 > EF4 > CF1 > the control. Soil microbial function group diversity decreased in the following order: EF2 > EF3 > EF1 > CF2 > EF4 > CF1 > the control, except for the Simpson index. Among these, only the richness index was significantly higher in the EF2 treatment than in the control. Among the six carbon sources used as substrates by the microorganisms, the polymer-type carbon source was the most preferred, while the opposite was true for the amine-type carbon source. The utilization rates of carbon sources were significantly higher in the EF2 treatment than in the control, except for carbohydrates. Nine main components were extracted, and the cumulative contribution rate was 92.33%. The variance contribution rate of the first principal component(PC1) was 25.46% and the second principal component variance was 17.24%. The contribution rate of carbon sources with PC1 was mainly polymers and carbohydrates, and PC2 contributed more carbon sources for carbohydrates and amino acids. Taken together, exponential fertilization with 80 mg/plant would be a more suitable fertilization mode and dose for light-medium seedlings. Under such conditions, the carbon source utilization rate, along with the soil microbial diversity and activity, can be greatly improved.