Improvement of subsoil physicochemical and microbial properties by short-term fallow practices

Abstract

Fallow management can improve the soil nutrients in the topsoil and upper subsoil. However, little is known about the effects of short-term (one year) fallowing with different treatments, such as vegetation and fertilization, on subsoil (20–40 cm) properties. We conducted field trials to explore the changes in subsoil properties in response to such treatments in the Yellow River Delta region in China. Different vegetation and fertilization treatments were applied, and we measured the carbon and nitrogen contents, microbial biomass and microbial community structure in the subsoil. Fallowing without manure resulted in the storage of more total nitrogen (16.38%) than fallowing with manure, and meadow vegetation improved the ammonium nitrogen content (45.71%) relative to spontaneous vegetation. Spontaneous vegetation with manure improved the microbial biomass nitrogen (P < 0.05). Although the impact of short-term fallowing on microbial community structure was low, an effect of management was observed for some genera. Blastopirellula, Lysobacter, and Acidobacteria Gp6 showed significant differences among fallow treatments by the end of the year (P < 0.05). Blastopirellula abundance was related to the microbial biomass nitrogen and nitrogen mineralization rate in the subsoil. Manure retained a high abundance of Lysobacter, which may strengthen soil-borne disease resistance. The response of Acidobacteria Gp6 showed that meadow vegetation without manure may not benefit future crops. Although the treatments did not significantly improve microbial community structure in the one-year period, annual fallowing improved certain subsoil properties and increased the number of functional genera, which may enhance crop productivity in the future.

PhoD Harboring Microbial Community and Alkaline Phosphatase as Affected by Long Term Fertilization Regimes on a Calcareous Soil

“…Fertilization significantly improved the relative abundance of Lysobacter while decreasing the relative abundance of Gemmatirosa and Afipia (Figure 3b). Our observation on Lysobacter was similar to that of other studies on alkaline saline alluvial soil, acidic black soil, or alkaline loess soil [73][74][75]. This may be due to the fact that bacteria of the genus Lysobacter have a good ability to colonize the root periphery of crops [76,77].…”

How to Improve the Benefits of Short-Term Fallow on Soil Physicochemical and Microbial Properties: A Case Study from the Yellow River Delta

“…It should be noted that native vegetation fallow with manure also increased microbial biomass N because plant diversity could promote nutrient-use efficiency [31]. In existing studies, this management method is also considered to be a relatively effective fallowing management method; however, considering its high cost, there may be some resistance in its actual implementation [13,25]. The analysis results of the different bacteria genera between the groups in the late fallow period showed that F-irrig, M-irrig, and M-ferti had the most obvious differences from the control group.…”

“…Combined with the relationship between the bacterium and microbial nitrogen, it can be seen that the increase in microbial nitrogen can inhibit nitrogen consumption and promote the growth of surface vegetation [40,41]. The bacterium Steroidobacter is closely related to denitrification, and it is negatively correlated with the microbial biomass carbon content and the microbial biomass carbon-nitrogen ratio, indicating that the control group is more likely to cause the emergence of denitrification, and the microbial biomass carbon content is low [13,42].…”

“…Based on previous studies on fallow cultivated land, this study shows that cultivated land conservation means can be mainly divided into vegetation construction, water, and fertilizer management [11][12][13][14]. Based on the commonly used vegetation types in local areas and combined with the mutualism and symbiosis of vegetation roots, different types of fallowing vegetation were constructed in our study.…”