Influence of phosphorus application and water deficit on the soil microbiota of N₂‐fixing and non‐N‐fixing tree

Abstract

Soil water content and phosphorus availability are important factors that are expected to shape soil microbiota. Although the impacts of water deficit (drought) on soil microbiota have been reasonably studied, microbial responses to P addition combined with soil water deficit have rarely been reported, especially in relation to the identity of aboveground tree species. This study was conducted to evaluate the main and interactive effects of drought and P addition on the soil protozoa, microbial communities as determined by phospholipids fatty acids (PLFAs) and enzyme activities in a soil vegetated with N2‐fixing or non‐N‐fixing tree species and in a non‐vegetated soil. The results indicated that the effects of drought, P addition, and their interaction on soil microbiota and chemical properties varied depending on the type of aboveground tree species. Drought significantly decreased the abundance of ciliates, amoebae, total protozoa, and most of the microbial community compared to the optimum water treatment, but the effect was more pronounced under non‐N‐fixers compared to N2‐fixers. P addition significantly increased the nitrate nitrogen (NO3−‐N) and dissolve organic nitrogen (DON) in drought treated soil as compared to the well‐watered counterpart, irrespective of the planting systems. The interaction of P with drought significantly increased the mean abundance of ciliates, flagellates, amoebae, and the total protozoa in soil vegetated with non‐N‐fixers and actinomycetes PLFAs, G+ bacterial PLFAs, and total bacterial PLFAs in the soil vegetated with N2‐fixers. Our finding points to an essential role of P addition and N2‐fixing trees on soil microbiota under drought stress. This study suggests that the effects of P application depend on its interaction with drought and that drought had decreasing effects on the abundance of ciliates, flagellates, amoebae, total protozoa, and the soil microbial communities, but the extent of it effects varied with tree species.

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

“…In our present study, compared to the normal soil moisture, drought markedly decreased the richness of the rhizosphere soil bacterial communities of A. inebrians, and the well-watered treatment significantly increased the richness of the rhizosphere soil bacterial community, and this supports our first hypothesis that soil moisture could influence the bacterial diversity in roots and rhizosphere soil of A. inebrians. Soil moisture, as a significant contributor to belowground bacterial community changes, has been reported to have profound effects on soil microbial activity, thus affecting carbon input as well as decomposition of soil organic matter, and this will contribute to plant growth (Zhang et al, 2014b;Naylor et al, 2017;Olatunji et al, 2018). Furthermore, previous findings indicated that soil properties are a major driver of differences in the distribution and composition of bacterial communities (Zhang et al, 2014b;Olatunji et al, 2018).…”

“…Soil moisture, as a significant contributor to belowground bacterial community changes, has been reported to have profound effects on soil microbial activity, thus affecting carbon input as well as decomposition of soil organic matter, and this will contribute to plant growth (Zhang et al, 2014b;Naylor et al, 2017;Olatunji et al, 2018). Furthermore, previous findings indicated that soil properties are a major driver of differences in the distribution and composition of bacterial communities (Zhang et al, 2014b;Olatunji et al, 2018). These soil properties include physical structure, microbial activity, organic compounds, nutrient transformation and the presence of root exudates (Zhang et al, 2014b;Francioli et al, 2016;Zhalnina et al, 2018).…”

Soil Microbial Community Structure and Physicochemical Properties in Amomum tsaoko-based Agroforestry Systems in the Gaoligong Mountains, Southwest China

“…The following PLFA-marks were used: (a) Gram-positive bacteria: a15:0, i15:0, i16:0, a17:0 and i17:0 [36]; (b) Gram-negative bacteria: 16:1ω7c, 16:1 2OH, cy17:0 [36,37], i17:1ω5c, 17:1ω8c [38], i17:0 3OH [39], 18:1ω5c [40], 18:1ω7c [41] and 11Me18:1ω7c [42]; 16:1ω11c was used as Nitrospira moscoviensis PLFA-mark [43,44], but can be used as an indicator for Gram-negative bacteria [45]; (c) non-specific bacteria: 15:0, 16:0 and 18:0; (d) 17:0 as general bacterial PLFAs [38]; (e) the fungi: 18:2ω6, 9c/18:0 ante [46,47] and 18:1ω9c [48,49]; (f) arbuscular mycorrhizal fungi (AMF): 16:1ω5c [50]; (g) actinomycetes was identified by 10Me16:0 [41], 10Me17:0 [49,51] and 10Me18:0 [48,49,51]. The sum of (a), (b), (c), and (d) represented total bacteria PLFA.…”

Planting Systems Affect Soil Microbial Communities and Enzymes Activities Differentially under Drought and Phosphorus Addition

“…Drought in the soil environment could affect microbial communities and enzyme activities, which are essential components in the biogeochemical processes. Moreso, reductions in water availability could limit or aggravate the effects of phosphorus deposition by enhancing its immobility in soil [ 3 ]. The use of fertilizers such as phosphorus (P) could decrease or increase the microbial biomass and may also exert selective forces on microbial groups by favoring some over the other, such as bacteria over fungi [ 3 , 4 , 5 ].…”

“…Moreso, reductions in water availability could limit or aggravate the effects of phosphorus deposition by enhancing its immobility in soil [ 3 ]. The use of fertilizers such as phosphorus (P) could decrease or increase the microbial biomass and may also exert selective forces on microbial groups by favoring some over the other, such as bacteria over fungi [ 3 , 4 , 5 ]. Dong et al [ 4 ] and Lie et al [ 5 ] reported that phosphorus addition increased total phospholipid fatty acid (PLFAs), bacterial PLFA, and fungal PLFA, Drought could induce osmotic stress on the plant, which might be accompanied by a trade-off between plant and soil, resulting in plants developing a range of adaptation strategies.…”