Effects of fertilizations on soil bacteria and fungi communities in a degraded arid steppe revealed by high through-put sequencing

Abstract

BackgroundFertilization as one of the measures in restoring degraded soil qualities has been introduced on arid steppes in recent decades. However, the fertilization use efficiency on arid steppes varies greatly between steppe types and years, enhancing uncertainties and risks in introducing fertilizations on such natural system to restore degraded steppes.MethodsThe experiment was a completely randomized design with five fertilization treatments, 0 (Control), 60 kg P ha−1 (P), 100 kg N ha−1 (N), 100 kg N ha−1 plus 60 kg P ha−1 (NP), and 4,000 kg sheep manure ha−1 (M, equaling 16.4 kg P ha−1 and 81.2 kg N ha−1). Soils were sampled from a degraded arid steppe which was consecutively applied with organic and inorganic fertilizers for three years. We analyzed the diversity and abundance of soil bacteria and fungi using high-throughput sequencing technique, measured the aboveground biomass, the soil chemical properties (organic carbon, available and total phosphorus, available and total nitrogen, and pH), and the microbial biomass nitrogen and microbial biomass carbon.ResultsIn total 3,927 OTU (operational taxonomic units) for bacteria and 453 OTU for fungi were identified from the tested soils. The Ace and Chao of bacteria were all larger than 2,400, which were almost 10 times of those of fungi. Fertilizations had no significant influence on the richness and diversity of the bacteria and fungi. However, the abundance of individual bacterial or fungi phylum or species was sensitive to fertilizations. Fertilization, particularly the phosphorus fertilizer, influenced more on the abundance of the AMF species and colonization. Among the soil properties, soil pH was one of the most important soil properties influencing the abundance of soil bacteria and fungi.DiscussionPositive relationships between the abundance of bacteria and fungi and the soil chemical properties suggested that soil bacteria and fungi communities in degraded steppes could be altered by improving the soil chemical properties through fertilizations. However, it is still not clear whether the alteration of the soil microbe community is detrimental or beneficial to the degraded arid steppes.

Effects of Epichloë gansuensis Endophyte on the Root and Rhizosphere Soil Bacteria of Achnatherum inebrians Under Different Moisture Conditions

“…Previous studies have shown that the diversity and composition of bacterial communities associated with plant roots and rhizosphere soil are affected by a series of biotic and abiotic factors, such as fertility, pH and soil moisture (Shen et al, 2013;Zhang et al, 2014b;Yao et al, 2018). These factors normally lead to changes in the physical and chemical properties of rhizosphere soil and soil nutrient levels, which are closely related to the diversity of rhizosphere soil and root bacteria (Bulgarelli et al, 2012;Fan et al, 2017;Francioli et al, 2017).…”

“…The composition and diversity of bacterial communities in soil and roots are considered as indicators reflecting plant biomass, mineral resources acquisition and biological processes, which are inevitably affected by host plant and environmental factors, including pH (Shen et al, 2013), nutrient availability (Meyer et al, 2013), soil moisture (Zhang et al, 2014b), and fertility (Yao et al, 2018). These factors alter rhizosphere soil microbial communities by changing soil physical and chemical properties, nutrient cycling and phytohormones production (Zhang et al, 2014b;Francioli et al, 2017;Zhalnina et al, 2018).…”

High-throughput sequencing analysis of the rhizosphere arbuscular mycorrhizal fungi (AMF) community composition associated with Ferula sinkiangensis

“…In contrast, in the present study we found that AMF community diversity was signi cantly positively correlated with soil pH, potentially due to unique local environmental factors. Some studies have shown that the tolerance of different AMF species to soil pH values varies greatly [50,51], and the diversity and community composition of AMF species in soils with different pH values were signi cantly different [52][53][54]. The soil pH range in the present study was from 7.80-8.81, with only certain Glomus and Diversispora AMF species being able to survive in this pH range.…”

High-throughput sequencing analysis of the rhizosphere arbuscular mycorrhizal fungi (AMF) community composition associated with Ferula sinkiangensis

“…In contrast, in the present study, we found that AMF community diversity was signi cantly positively correlated with soil pH, potentially due to unique local environmental factors. Some studies have shown that the tolerance of different AMF species to soil pH varies greatly [50,51], and that the diversity and community composition of AMF species in soils with different pH values were signi cantly different [52][53][54]. The soil pH range in the present study was from 7.80-8.81, with only certain Glomus and Diversispora AMF species being able to survive in this pH range.…”