[Phosphorus characteristics in rhizosphere soil of Cunninghamia lanceolata, Pinus massoniana and their mixed plantations].

In 2007-2010, a comparative study was conducted on the phosphorus characteristics in the rhizosphere soil of Cunninghamia lanceolata, Pinus massoniana and C. lanceolata-P. massoniana mixed plantations in a forest farm in Nanping City of Fujian Province, East China. In the rhizosphere soil of pure C. lanceolata and P. massoniana plantations, the content of available P was higher than that in non-rhizosphere soil. As compared with non-rhizosphere soil, the rhizophere soil in the three plantations had lower pH and O-P content but higher Al-P and Fe-P contents, and its P adsorption capacity was lower while the P desorption rate and desorbed P were in adverse. In the rhizophere soil of pure P. massoniana plantation, the contents of available P, Fe-P, and Al-P, their desorption rates, and desorption capacity were higher, but the O-P content and the adsorbed P were lower, as compared with those in the rhizophere soil of pure C. lanceolata plantation. In the mixed plantation, the P activation in rhizophere soil was further improved, being more obvious under C. lanceolata, which suggested that mixed plantation of C. lanceolata and P. massoniana could promote the phosphorus nutrition of C. lanceolata.