Soil Respiration from Different Halophytic Plants in Coastal Saline-Alkali Soils

Cultivation and growing salt-tolerant (halophytes) plants in coastal saline-alkali soils has been regarded as an effective way to reduce soil salinization and restore degraded vegetation. Planting halophytic plants generally alters soil properties and indirectly influences soil respiration. The aim of this paper is to evaluate the seasonal variation in soil respiration under different vegetation types in coastal saline-alkali land in northern China, and to identify how tree species, stand age, and soil properties (soil temperature, moisture, and salinity) explained the temporal and spatial variation in soil respiration. Soil respiration from halophytic plants (Tamarix chinensis and Lycium chinense) and salinealkali bare land were measured using an LI-COR 6400XT portable photosynthesis system equipped with a portable soil CO2 flux chamber from May to October 2016. The results indicated that T. chinensis and L. chinense shrub communities significantly reduced soil salinity, slightly reduced soil bulk density, improved soil organic carbon, and promoted the microbial community. Soil respiration from T. chinensis and L. chinense plantations were significantly higher than that from bare land. Coastal salinized bare land is a weak carbon source for global carbon. Soil respiration was generally restrained by soi salinity and reduced with increasing soil salinity. Soil respiration showed a positive and negative correlation ith soil temperature, moisture, and salinity. Incorporating salinity, together with soil temperature and other abiotic factors, may improve predictions for soil CO2 respiration.