Responses of Soil Microbial Biomass and Enzyme Activities to Natural Restoration of Reclaimed Temperate Marshes After Abandonment

Abstract

Restoration of reclaimed marshes has great effects on soil biological processes. However, the responses of soil microbial properties (microbial biomass and enzyme activities) to natural restoration of reclaimed marshes is poorly studied, especially in a long restoration chronosequence. This study assessed the responses of soil microbial properties to natural restoration and investigated the relationships between soil microbial properties and soil physico-chemical and plant properties. We selected a restoration chronosequence (1, 4, 8, 13, 17, 27 years) after farmland abandonment, a soybean field, and a natural marsh in Sanjiang Plain, northeast China. For each site, we analyzed the soil microbial biomass carbon and nitrogen (MBC and MBN), four enzymes (β-glucosidase, invertase, catalase, urease) activities, soil physico-chemical properties at 0–50 cm depths, and plant properties (biomass, height, and coverage). The MBC and MBN contents increased with restoration time, but MBN content slowed down after 8 years of restoration. After 27 years of restoration, the soil MBC and MBN contents were 15.7 and 3.2 times of those in the soybean field, but the largest contents of MBC and MBN in the restored sites were 7.78%, 27.76% lower than those in natural marshes, respectively. Moreover, soil enzyme activities and the geometric mean of enzymatic activities (GME) also increased with restoration but slowed down after 13 years of restoration. After 27 years of restoration, the GME was 2.9 times than that in the soybean field, but the largest GME in the restored sites was 31.15% lower than that in the natural marsh. MBC and MBN contents, soil enzyme activities, and GME had significant relationships with soil C:N ratio, organic carbon, nutrients (total nitrogen, available nitrogen, total phosphorus), bulk density, moisture content, pH, plant properties, (i.e. biomass, height, and coverage) (p < 0.01). Redundancy analysis revealed that soil C:N ratio, pH, moisture content, total nitrogen and phosphorus were main factors affecting MBC and MBN contents and enzyme activities. In conclusion, soil microbial properties can respond positively to the natural restoration process of the reclaimed marshes and were significantly correlated with specific parameters of soil physico-chemical and plant properties.

Effects of Chinese Milk Vetch Returning on Soil Properties, Microbial Community, and Rice Yield in Paddy Soil

“…Furthermore, SOC and AN were the main soil environmental factors affecting rice yield (Figure 4), in accordance with previous results [15]. In addition, markedly negative relationships among soil BD, bacterial Shannon diversity index, and rice yield were found in our study; previous studies also had similar reports [44,58].…”

Characteristics of soil organic carbon fractions in four vegetation communities of an inland salt marsh

“…It was found that SOC, DOC, POC, and MBC were positively correlated with SWC and TN, and negatively correlated with SBD. This is mainly because of the increase of soil moisture for plant litter decomposition and soil microbial activity, which would be helpful to the accumulation of soil organic carbon components together [ 46 ]. The higher the soil moisture content, and soil aeration, the less number of aerobic bacteria, SOC mineralization process is abated, the organic material input is greater than the output, the long-term accumulation of soil organic carbon content increased [ 29 , 47 ].…”

Responses of soil enzyme activities and bacterial community structure to different hydrological regimes during peatland restoration in the Changbai Mountain, northeast China

“…The hydrolysis enzyme activities (βG, NAG, and AP) in degraded peatland were significantly lower than those in natural peatland, this may be due to the sharp decrease in soil organic matter after peat reclamation. Previous studies also reported lower soil enzyme activities in agricultural or farm abandoned peatland than those in natural peatland (Wang et al, 2021). Peat cultivation can lead to rapid organic matter decomposition, and the nutrients released change to mobile forms that can be easily leached (Glina et al, 2016).…”