Effect of Soil Amendment with Microbes on Physical and Chemical Properties of Reclaimed Saline Soil in Coastal Areas

Abstract

【Background】 Tidal flat is a natural ecological system with multiple functions for regulating coastal environments. Soil in most tidal flats in China is rich in sodium chloride but is poorly structured, short of organic matter and nutrients such as nitrogen and phosphorus, which undermine the ecological services the flats are expected to provide. Remediating tidal flats is therefore imperative to improve their functions, a key in which is to improve soil permeability and aggregation so as to facilitate salt leaching and plant growth. 【Objective】 The purpose of this paper is to elucidate the feasibility of using fungi hyphae as a soil conditioner to improve soil quality and reduce water evaporation. 【Method】 We compared four remediating treatments: reclaiming the coastal soil only (RCS), conventional remediation coupled with freshwater washing and cattle manure application (CVT), CVT plus planting Sesbania cannabina (SES), amending the soil with fungi hyphae (MCMs), MCMs plus planting Sesbania cannabina (MCT). The efficacy of MCMs at improving physical and chemical properties of soil, as well as salt leaching and growth of the S. cannabina was measured and compared with other treatments. 【Result】 Compared to SES, MCMs significantly increased the biomass of S. cannabina (P<0.05) by 75.83%. Compared to RCS, MCT increased: ①the field capacity of the 0~10 cm soil by 25.23%; ②bulk density of soil in 0~10, 10~20 and 20~30 cm layers by 9.52%, 9.46%, 8.67%, respectively; ③water content in 0~10, 10~20, 20~30 cm layers by 37.34%, 36.17% and 19.67%, respectively; ④the capillary porosity in 0~10, 10~20, 20~30 cm layers by 14.55%, 13.33% and 10.54% respectively; ⑤the available P in 0~10, 10~20, 20~30 cm layers by 160.52%, 297.58% and 280.84%, respectively; ⑥the available K in 0~10, 10~20, 20~30 cm layers by 186.25%, 90.08 % and 6.00 %, respectively; ⑦the organic matter content in 0~10, 10~20 and 20~30 cm layers by 505.88%, 594.44% and 372.45% respectively; ⑧the soluble salt content in 0~10, 10~20, 20~30 cm layers by 87.25%, 85.44% and 77.12% respectively. 【Conclusion】 MCT increased permeability of the surface soil to infiltrate precipitation and reduced the evaporation, thereby alleviating secondary salinization. Our results also showed that MCMs significantly increased the biomass of S. cannabina and soil nutrients, accelerating salt migration as a result.

Keywords

• coastal area
• microbial mulching
• saline soil
• soil physical and chemical properties
• sesbania cannabina