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Fertilizer Timing And Formulation Affect Flowering In A Loblolly Pine Seed Orchard

Fertilizer trials in a Mississippi seed orchard showed that N stimulated flowering, P did not, and N + P was no better than N alone. Of three nitrogen sources tested, NH4NO3 proved most effective in one experiment; but response to NH4NO3 and to NaNO 3 was about the same in another experiment. Fertilizing in mid to late summer produced the greatest increase in flowering (as much as 300 percent); the best treatment (fertilized July 26) tripled cone yield and quadrupled yield of sound seed. Fertilized ramets were no taller than controls, but diameter growth was improved by treatments. Clone x treatment interactions were always significant.

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Author(s): Ronald C. Schmidtling

Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1975