Abstract：Labile phosphorus was considered as an important phosphorus pool in soil and played essential roles in soil phosphorus cycling. Based on a 90-day laboratory experiments, the effects of three greenhouse factors including environmental temperature, soil acidification and salinization on soil labile phosphorus were studied through the dynamics of readily desorption phosphorus (CaCl2-P), available phosphorus (Olsen-P), microbial biomass phosphorus (MB-P) and ratio of microbial biomass carbon to phosphorus (MB-C/P) in greenhouse soil. Results showed that MB-P content in the greenhouse soil was increased significantly with the rising of environmental temperature. Compared with the control (incubated under 4℃), the contents of CaCl2-P and Olsen-P in the greenhouse soil were increased by 15.6% and 2.7% under 10℃ at the end of incubation, respectively. Acidification of greenhouse soil promoted an increase in the contents of CaCl2-P and Olsen-P but a decrease in the MB-P content. Compared with the control (at pH 6.89) at the end of incubation, it was increased by 26.7% and 156.1% for CaCl2-P content, increased by 14.1% and 91.5% for Olsen-P content, but decreased by 13.3% and 16.3% for MB-P content in acidified soil at pH 6.11 and 5.30, respectively. Soil salinization showed no significant effect on the contents of CaCl2-P and Olsen-P in soil, whereas soil MB-P content was decreased dramatically with the aggravation of salinization after 12days of incubation. Compared with the control (1.90g/kg for soluble salt in soil), MB-P content in salinized soils with 3.05g/kg and 5.01g/kg of soluble salt was decreased by 42.2% and 45.8%, respectively. In addition, the MB-C/P in greenhouse soil after 40-day incubation showed a general downtrend with the increment in environmental temperature, soil acidification and salinization. Therefore, it was concluded that management practices, such as increasing environmental temperature in a range of 4~25℃, slowing down the acidification process of soil pH value from 6.89 to 5.30, and controlling the salinization process of soil soluble salt from 1.90g/kg to 5.01g/kg, could keep supplying phosphorus in greenhouse soil to plants. These practices could also reduce the risk of phosphorus loss from soil, and enhance the potential of available phosphorus pool which were regulated by soil microorganisms.
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