Soil microorganisms play crucial roles in nutrient cycling and determining soil quality and fertility; thus, they are important for agricultural production. However, the impacts of long-term fertilization on soil microbial community remain ambiguous due to inconsistent results from different studies. The objective of this study was to characterize changes in bacterial and fungal diversity and community structures after 12 years of different fertilization in aeolian sandy soil by analyzing 16S rRNA and ITS rRNA gene sequences and the soil properties to discover the driving factors. Eight different fertilizer treatments have been set up since 2009: no fertilizer (CK), chemical N fertilizer (N), chemical N and P fertilizer (NP), chemical N, P and K fertilizer (NPK), pig manure only (M), pig manure plus chemical N fertilizer (MN), pig manure plus chemical N and P fertilizer (MNP), pig manure plus chemical N, P, and K fertilizer (MNPK). The results indicated that the long-term application of chemical fertilizer reduced soil pH, whereas the addition of pig manure alleviated a decrease in soil pH value. Chemical fertilizer plus pig manure significantly improved soil available nutrients and soil organic carbon. Long-term MNPK fertilization resulted in changes in bacterial diversity due to effects on specific bacterial species; by contrast, all fertilization treatments resulted in changes in fungal diversity due to changes in soil properties. Principal component analysis indicated that fertilization had a significant effect on soil microbial community structure, and the effect of chemical fertilizer combined with pig manure was greater than that of chemical fertilizer alone. Soil available phosphorus, total phosphorus, and pH were the most important factors that influenced bacterial taxa, whereas soil pH, total phosphorus, organic carbon, ammonium nitrogen and nitrate nitrogen were the most important factors influencing fungal taxa after 12 years of fertilization in aeolian sandy soil.

Long-term rotation fertilisation has differential effects on soil phosphorus | Xue Li, Qiu-Xiang Wen, Shi-Yu Zhang, Na Li, Jin-Feng Yang, Xiaori Han | Agricultural Journals

Organic fertilization in no‐till soils increases soil organic matter and nutrient pools primarily in surface soils. However, little is known about how microbial activity affects crop access to phosphorus (P) forms at the surface, where the organic fertilizer is applied, and the subsurface, the main rooting zone. We aimed to study the changes in organic and inorganic P (Po; Pi) forms and compounds in no‐till compost amended surface (0–5 cm) and subsurface (5–15 cm) soils growing a crop rotation for 2 years in pots. Crops were grown in pots with compost amended to the soil surface, while unamended and compost‐amended pots without crops were used as controls. We measured changes in microbial C (carbon), soluble C, total Po and Pi forms, the moderately accessible EDTA‐NaOH‐Pi (‐Po), and labile NaHCO ₃ ‐Pi (‐Po). P compounds in the EDTA‐NaOH extract were measured by ³¹ P‐NMR. Compost addition increased the levels of total Pi and although it had no effect on total Po, increases of inositol, other phosphate monoesters and orthophosphate diesters could be observed. After the application of compost, the amount of total organic C, soluble carbon and all P forms increased in surface soil, while in the subsurface soil, there was a reduction in organic C and an increase in soluble C, total Pi, EDTA‐NaOH‐Pi and NaHCO ₃ ‐Pi and the EDTA‐NaOH‐Po and labile NaHCO ₃ ‐Po. Growing crops reduced all measured Pi forms and labile NaHCO ₃ ‐Po, increased EDTA‐NaOH‐Po in surface soils and had no observable impact on total Po in either organic C‐enriched surface or organic C‐reduced subsurface soils. Crops mostly used Pi from the low P availability C‐reduced subsurface layer, where NaHCO ₃ ‐Po pools also decreased. Large reductions in NaHCO ₃ ‐Po and increased levels of IHP and other‐monoesters in crop‐growing organic C‐enriched surface layers may suggest microbial formation of monoesters Po and crop use of labile Po pools. In summary, Po formation in C‐enriched surface layers and the mobilization of all Pi forms throughout the soil profile are particularly important findings for the understanding of P dynamics in compost‐amended no‐till systems.