Leaf Nutrient Diagnosis of Second Generation Seed Orchard of Pinus massoniana Treated by Different Fertilizers

In March 2021, experiments were conducted on application of 16 formula fertilizers of N, P, K, Ca, Mg, B and 3 concentrations of Mo in second generation seed orchard of Pinus massoniana in Shaowuweimin Forest Farm, Nanping, Fujian province. In December 2021, determinations were carried out on their leaf nutrient content and seed yield. The results showed that there was correlation between seed yield and leaf nutrients, like contents of P and Mo in leaves had extremely significant (P<0.01) or significant (P<0.05) positive relation with seed yield, and the effect of P on seed yield was higher than that of Mo. Interaction among N-B, P-K, P-Ca, P-Mg, P-Mo could promote seed orchard yield, while that among N-P, N-Mo, P-B, K-B, K-Mo, Mg-B had the opposite effect on seed yield. There was also interaction among leaf nutrients, N-Mo, P-K, P-B, P-Mo, K-B, P-Ca, P-Mg and Mg-B were synergetic, while N-P, N-B and K-Mo antagonistic. The theoretical maximal seed yield of single mother P. massoniana tree in the test site was 31.92 g. The suitable content range of seven nutrients in the mother tree leaves was as follows: N (13.568-16.228 g/kg), P (2.718-5.078 g/kg ), K (9.913-15.433 g/kg), Ca (0.633-2.763 g/kg ), Mg (0.855-1.755 g/kg ), B (26.639-44.959 mg/kg ) and Mo (2.076-3.436 mg/kg ).