Potential application of oat for phytoremediation of salt ions in coastal saline-alkali soil

Abstract

Improvement of saline-alkali soils by biological means is a strategic soil conservation method. To investigate the capacity of oat for phytoremediation, two factor randomized block design experiments are carried out in coastal North China. The two factors — oat variety (“Ba You-1” – BU, “Hua Zao-2” – HZ and “Bai Yan-2” – BY) and soil salinity (1.0, 2.0 and 3.0gkg−1) — are analyzed for oat biomass, straw ion accumulation and straw-to-soil ion concentration ratio. Results show that oat biomass be affected by harvest time and soil salinity. BU biomass decreases by 0.4tha−1 for harvest delay by 20 days. And BY biomass drops severely which from 3.1tha−1 in low soil salinity to 0.4tha−1 in high soil salinity. The straw ion concentration (except Ca2+) significantly drops when harvest is delayed, but it increases with soil salinity increases though K+ concentration markedly decreases. For the straw ion accumulation, the highest value for harvest time is at maturity (146.4kgha−1 for BU) and for soil salinity is at low level (100.2kgha−1 for BY) and it turns sharp decrease with the time delaying and soil salinity increasing. Ions changes in stem significantly lower than that of in leaf whatever delay harvest time or increases soil salinity. Under medium soil salt concentration, the straw-to-soil total ion concentration ratios are respectively 31.7, 32.5 and 31.3 for BU, BY and HZ. The correlation analysis reveals that oat ion accumulation is positively correlated with biomass. Besides, straw Na+ and Cl− accumulation is respectively negatively (p<0.05) correlated with K+. According to above that oat is a potential plant species in improvement of saline soil. However the low biomass and salinity tolerance limit its practical application in coastal saline-alkali soils North China.