Effects of temperature and phosphorus application on wheat growth at seedling stage and phosphorus form in calcareous fluvo-aquic soil

Abstract

The effects of temperature and phosphate fertilizer application on wheat seedling growth and soil inorganic phosphorus transformation in calcareous fluvo-aquic soil were examined in a pot experiment. The results showed that temperature and phosphorus were important factors affecting wheat growth but without significant interaction. The effect of temperature on wheat growth was greater than that of phosphate fertilizer, and 15 ℃ was the suitable temperature for wheat seedling. Compared with the treatment without P application (-P) at 5 ℃, phosphate fertilizer treatment (+P) promoted the growth of wheat seedling. Shoot and root biomass increased by 18.2% and 33.3%, the accumulation of phosphorus in shoot and root were increased by 30.6% and 13.3%, and the root-shoot ratio, plant height, tillering number and root activity were increased by 3.5%, 10.0%, 10.5% and 70.3%, respectively. At 15 ℃, the effect of phosphorus fertilizer application did not affect wheat biomass and tiller, increased P accumulation in shoot and root of wheat by 32.3% and 23.8%, and increased the ratio of root to shoot, plant height and root activity by 15.6%, 2.5% and 32.8% respectively. There were no significant promoting effects on wheat growth between different phosphate applications at 25 ℃. At three temperatures, phosphate application significantly increased the contents of Olsen-P, Ca2-P, Ca8-P, Al-P and Fe-P. When treated with -P and +P, temperature had no significant effect on Ca2-P content, but had significant effect on the Olsen-P, Ca8-P, Al-P, Fe-P contents. The contents of Ca8-P and Fe-P were 5 ℃＞15 ℃＞25 ℃; Al-P content was 25 ℃＞15 ℃＞5 ℃. Wheat could absorb and utilize Ca2-P, Ca8-P, Al-P, Fe-P at seedling stage. The availability of Al-P, Fe-P to wheat was significantly lower than that of Ca2-P, Ca8-P. There was no significant difference of soil pH, O-P and Ca10-P across all treatments. In conclusion, temperature mainly affected the absorption of phosphorus by affecting wheat growth, and the application of phosphorus fertilizer at low temperature could significantly promote the growth of wheat. High temperature could accelerate the fixation of available phosphorus in calcareous soil, a process could be alleviated by phosphorus application.