Weijun Zhou;Kairong Wang;Zhang Yang-zhu;Lichu Yin;Hesong L

Institute of Subtropical Agriculture ,Chinese Academy of Sciences, Changsha 410125,China);College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China);College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China;College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China.; Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China)

32p;intercropping;soybean;applied;citrus;p

A mini-plot field experiment was conducted on a loamy clay Oxisol to compare and evaluate P absorption and transfer in plant organs and P movement in soil profile at three P application depths under the soybean-citrus intercropping versus the monoculture using a P-32 tracer technique. Total P absorption (P-t) by soybean and P accumulation (P-a) in soybean organs decreased significantly (P < 0.05) under the intercropping in contrast to the monoculture. With intercropping, when P-32 was applied in topsoil (15 cm soil layer), total P-32 absorption (P-32(t)) in soybeans was significantly lower (P < 0.05), but when 32p was applied to deeper soil layers (35 or 55 cm soil layer), P-32(t) in soybeans was significantly greater (P < 0.05). The percentage of P in leaves to total P (P-a/P-t) and P-32 in leaves to total P-32 (P-32(a)/P-32(t)) for soybean were >= 25% and those of root >= 12%. When P was applied in topsoil and 55 cm soil layer, no significant differences were found between intercropping and monoculture for P-t of citrus. The P absorbed by citrus was transferred rapidly to the growing organs of aboveground during the experiment, and the speed of transferring to the growing organs slowed when P was applied to the deeper soil layers. In intercropping, P mobility was heightened in the soil profile, and P in deeper soil layers moved up to topsoil more rapidly.