Abstract:

In order to choose a more appropriate time for sampling of the second generation rubber plantation nutrition diagnosis, field experiment was carried out to find the leaf nutrient content differences in October of 2008, in April and July of 2009. The results showed that: in April of 2009, leaf N, P and Mg content showed a significant positive correlation with that in October of 2008, while the K and Ca content showed a no significant correlation; in July, 2009, leaf N, P, Ca content showed a significant positive correlation with that of October, 2008, the Mg content had a highly significant positive correlation, while no significant correlation of K content; in July, 2009, leaf N, K content had no significant correlation with that of April, 2009, while the P, Ca, Mg content showed positively correlation. Further research showed that, the value of leaf N, P and Mg content forecasted by October, 2008, had a highly significant positive correlation with the actual determined value of that of April, 2009. Therefore, October of the the previous year could be a suitable sampling time for the nutrition diagnosis of the following year.