Reshaping of soil properties and microbial community by the conversion from non-grain cultivated land to paddy field

Xuqing LI¹Han Chen¹Xiao Wang²Qurban Ali^3*Luqiong Lv⁴Tiefeng Zhou¹Munazza Ijaz⁴Temoor Ahmed^4,5Jianli Yan^1*Bin Li^4*

• ¹Institute of Vegetable, Hangzhou Academy of Agricultural Sciences, Hangzhou 310024, China., Hangzhou, China
• ²Ningbo Jiangbei District Agricultural Technology Extension Service Station, Ningbo, China., Ningbo, China
• ³United Arab Emirates University College of Science, Al Ain, United Arab Emirates
• ⁴Institute of Biotechnology, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
• ⁵Western Caspian University, Baku, Azerbaijan

In order to ensure food security, China is actively carrying out conversion of non-grain cultivated land to paddy field. Therefore, it is very necessary to investigate the influence of this conversion on soil health, which has been well known to play an important role in crop growth. A combined analysis of soil physicochemical properties, bacterial community structure, and metabolite was conducted on 72 soil samples, which were collected in this study from the converted paddy fields and the corresponding non-grain cultivated lands including loquat garden, mulberry field, blueberry garden, vineyard, bamboo garden and nursery stock base. Results from this study indicated that conversion of non-grain cultivated land to paddy field significantly influenced physicochemical properties, bacterial community structure, and metabolite of root-zone soil with 8.08-43.85%, 8.90-64.14%, 24.98-91.97%, 38.74-92.52%, and 5.12-32.99% reduction in organic matter content (SOM), alkaline hydrolysis nitrogen (AHN), available phosphorus (AP), available potassium (AK), and microbial biomass carbon (MBC), respectively; 0.81-3.08 fold, 1.26-21.50 fold, and 4.29-14.54 fold increase in relative abundance of Chloroflexi, Desulfobacterota, and Nitrospirota, respectively; and 2,204 differentially expressed metabolite (DEMs) belonging to amino acids and derivatives, benzene and substituted derivatives, flavonoids, lipids, organic acids, terpenoids. Furthermore, correlation analysis indicated that these DEMs were significantly correlated with some specific bacteria, thereby helping in coordinating the root-zone soil community during conversion, while these bacteria were also correlated with soil properties. The results revealed that non-grain cultivation caused a significant alteration in physicochemical properties, bacterial diversity, richness and community structure, metabolite of root-zone soils, while the extent of the change depends on the type of non-grain conversion. In conclusion, this study highlights the importance of bacterial communities during conversion of non-grain cultivated land to paddy field, which provided a scientific basis and supporting evidence for the renovation of non-grain cultivated land.