Effects of Different Microbial Fertilizers on Growth and Rhizosphere Soil Properties of Corn in Newly Reclaimed Land

Abstract

Land reclamation may expand the supply of usable land for food security. Soil microorganisms have been considered as an amendment in immature soil to improve its quality. However, different microbial fertilizers' effects on plant growth in immature soil have largely been unexplored. In order to evaluate the effects of different microbial fertilizers on immature soil, the soil quality and microbial community structure of corn rhizosphere soil samples under different microbial fertilizers were investigated. The results revealed a significant difference between microbial fertilizers (especially seaweed microbial fertilizer, SMF) and commercial chemical compound fertilizers in the soil properties and microbial community structure. Indeed, SMF caused a 486.21%, 23.17%, 21.08%, 38.33%, and 482.39% increase in Flavobacteriaceae, Planctomycetaceae, Chitinophagaceae, Acidobacteria_Gp3, and Mortierellaceae but a 23.82%, 18.66%, 42.36%, 29.12%, 81.97%, 42.19%, and 99.33% reduction in Cytophagales, Comamonadaceae, Rhodospirillaceae, Sinobacteaceae, Aspergillaceae, Myrmecridiaceae, and Typhulaceae, respectively; while CCF caused an 85.68% and 183.22% increase in Xanthomonadaceae and Mortierellaceae but a 31.29%, 36.02%, and 65.74% reduction in Cytophagales, Spartobacteria, and Cyphellophoraceae compared with the control based on 16S and ITS amplicon sequencing of soil microflora. Furthermore, redundancy discriminant analysis of the microbial communities and soil properties indicated that the main variables of the bacterial and fungal communities included exchangeable Ca, organic matter content, total N, and available P. Overall, the results of this study revealed significant changes under different fertilizer conditions in the microbiota and chemical properties of corn soil. Microbial fertilizers, particularly SMF and SM, can be used as a good amendment for newly reclaimed land.

Keywords: corn; land; microbial fertilizer; microbiome; soil.

Figure 1

Experimental site for the evaluation of different fertilizers on the growth of corn in newly reclaimed land. (a) Soil with different fertilizers; (b) plantation of corn.

Figure 2

Effects of different microbial fertilizers on the OUT distribution (a), the Chao1 index (b) and the Shannon’s diversity index (c) of bacteria and fungi in corn rhizosphere soil. T1, T2, T3, T4, T5, and CK represents the treatment of Tuzangjin microbial fertilizer (TMF), carbonergic microbial agent (CMA), seaweed microbial fertilizer (SMF), sheep manure (SM), chemical compound fertilizer (CCF), and the control (CK), respectively. Values with different lowercase letters within the same treatments indicate significant differences (p < 0.05).

Figure 3

PCA results of soil bacteria (a) and fungi (b) based on OUT abundance. T1, T2, T3, T4, T5, and CK represent the treatment of Tuzangjin microbial fertilizer (TMF), carbonergic microbial agent (CMA), seaweed microbial fertilizer (SMF), sheep manure (SM), chemical compound fertilizer (CCF), and the control (CK), respectively.

Figure 4

Relative abundance of bacteria (a) and fungi (b) at the phylum level. T1, T2, T3, T4, T5, and CK represent the treatment of Tuzangjin microbial fertilizer (TMF), carbonergic microbial agent (CMA), seaweed microbial fertilizer (SMF), sheep manure (SM), chemical compound fertilizer (CCF), and the control (CK), respectively.

Figure 5

Relative abundance of bacteria (a) and fungi (b) at the genus level. T1, T2, T3, T4, T5, and CK represent the treatment of Tuzangjin microbial fertilizer (TMF), carbonergic microbial agent (CMA), seaweed microbial fertilizer (SMF), sheep manure (SM), chemical compound fertilizer (CCF), and the control (CK), respectively.

Figure 6

Linear discriminant analysis (LDA) effect size (LeFse) of the bacterial taxa (a), which identifies the most differentially abundant taxa among the different microbial fertilizer treatments. Only taxa with LDA values greater than 4 (p < 0.05) are shown. Hierarchical clustering analysis and heat mat at the family level (b). The tree plot represents a clustering analysis of the top 20 bacteria at the family level according to their Person correlation coefficient matrix and relative abundance; the upper tree plot represents a clustering analysis of soil samples according to the Euclidean distance of data. T1, T2, T3, T4, T5, and CK represent the treatment of Tuzangjin microbial fertilizer (TMF), carbonergic microbial agent (CMA), seaweed microbial fertilizer (SMF), sheep manure (SM), chemical compound fertilizer (CCF), and the control (CK), respectively.

Figure 7

Linear discriminant analysis (LDA) effect size (LeFse) of the fungal taxa (a), which identified the most differentially abundant taxa among the different microbial fertilizer treatments. Only taxa with LDA values greater than 4 (p < 0.05) are shown. Hierarchical clustering analysis and heat mat at the family level (b). The tree plot represents a clustering analysis of the top 20 fungi at the family level according to their Person correlation coefficient matrix and relative abundance; the upper tree plot represents a clustering analysis of soil samples according to the Euclidean distance of data. T1, T2, T3, T4, T5, and CK represent the treatment of Tuzangjin microbial fertilizer (TMF), carbonergic microbial agent (CMA), seaweed microbial fertilizer (SMF), sheep manure (SM), chemical compound fertilizer (CCF), and the control (CK), respectively.

Figure 8

Redundancy discriminant analysis (RDA) of the rhizosphere bacterial (a) and fungal (b) community compositions at the genus level with the soil physicochemical properties. Sph: Sphingomonas; Gem: Gemmatimonas; Fla: Flavobacterium; Sub: Subdivision3; Ari: Aridibacter; Lac: Lacibacterium; Chr: Chryseolinea; Lys: Lysobacter; Pir: Pirellula; Pse: Pseudomonas; Rhi: Rhizobium. Mor: Mortierella; Myrm: Myrmecridium; Asc: Ascobolus; Cyp: Cyphellophora; Bol: Bolbitius; Fus: Fusarium; Psa: Psathyrella; Par: Paramyrothecium; Cer: Cercophora; Asp: Aspergillus; Pye: Pyrenochaetopsis; Pod: Podospora; Myr: Myrothecium; Cla: Cladorrhinum; Gib: Cladorrhinum. OMC: organic matter contain; TN: total N; AP: available P; AK: available K; exCa: exchangeable Ca; exMg: exchangeable Mg. T1, T2, T3, T4, T5, and CK represent the treatment of Tuzangjin microbial fertilizer (TMF), carbonergic microbial agent (CMA), seaweed microbial fertilizer (SMF), sheep manure (SM), chemical compound fertilizer (CCF), and the control (CK), respectively.