Abstract:In order to identify the amelioration of uncultivated saline wasteland, transformation of phosphorus (P) fraction after different plants plantation in the Yellow River Delta, we investigated the dynamics of P fractions and availability after the uncultivated saline wasteland with reed (RU) was reclaimed by plantation of Chinese tamarisk (CT), Chinese ash (CA) and clover (C). Results showed that the phosphatase activity of 0—20 cm soil were significantly increased by 3 plants plantation compared with RU. CT plantation significantly decreased soil pH of 0—20 cm soil, while it significantly increased soil organic carbon (SOC) concentration of 0—40 cm soil and promoted the formation of large size aggregate particles of 0—20 cm soil, but it significantly increased soil salinity of 0—100 cm soil and accelerated transformation of P fractions from soluble P (Ca2—P) or slowly soluble P (Ca8—P and Al—P) to insoluble P (Ca10—P) that reduced P availability. CA plantation could significantly decrease soil salinity of 0—100 cm soil and pH of 60—100 cm soil, while it accelerated transformation of P fractions from insoluble P (O—P) to slowly soluble P (Fe—P), but it increased ratio of small size aggregate particles of 0—20 cm soil and decreased SOC concentration of 0—40 cm soil that were beneficial to improve P availability. C plantation could significantly increase soil available P concentration of 0—20 cm soil with improved soil phosphatase activity of 0—20 cm soil which was much higher than those of other 3 plants. While it accelerated transformation of P fractions from insoluble P (O—P) or slowly soluble P (Ca8—P and Al—P) to soluble P with accelerated formation of large size aggregate particles of 0—20 cm soil. Soil microbial nitrogen was significantly increased by plantation of CT, CA and C, but soil microbial carbon and soil microbial phosphorus were significantly decreased. No significant difference was observed on soil respiration and urase activity. In this study, Chinese ash plantation could decrease soil salinity and soil pH, while clover plantation could promote soil P availability of 0—20 cm soil. Plantation of all 3 plants had no significant beneficial effect on P availability in 20—100 cm soil. However, more research is necessary to explore the long-term dynamics of soil microorganisms community and regulation mechanism on P fraction by soil microorganisms in the saline land.