Abstract: The results from a six years field experiment conducted on a calsic cinnamon soil indicated that there was no significant difference between the crop yields from two different ways of applying phosphorus fertilizer——once every six years with high rate and once every year with low rate, the latter gave a little more yields than the former, but was more effective in establishing soil available phosphorus pool. The residual effect from one application of phosphorus seemed to last more than five years on the calsic cinnamon soil, and thus, although the recovery of phosphorus was as low as 7% at the first year of application with high rate, the total recovery in six years was as high as 34%. The proportion of residual phosphorus transfering into soil available phosphorus pool was about 17% after six years of applying phosphorus every year with low rate, but only 2% from one application with high rate.

Key words: Phosphorus, Residual effect, Phosphorus recycling, mini-UAV image, estimation of scale parameter, supervised classification, visible vegetation index, object-oriented image classification., aquatic vegetation