Effects of combined application of organic and chemical fertilizers on growth of young Neolamarckia cadamba plantation

Objective To explore effects of combined application of organic and chemical fertilizers on growth of young Neolamarckia cadamba plantation(YNCP).

Method Impacts of combined application of pig manure, chicken manure, calcium superphosphate and potassium chloride on YNCP growth were studied by using orthogonal test.

Result Combined application of organic and inorganic fertilizers had significant promoting effects on YNCP growth, with height and ground diameter growth of fertilized treatments being 23.53% -109.41% and 37.99%-149.06% greater than those of control treatment, respectively. Multivariate analysis indicated that pig manure and calcium superphosphate had significant effects on height and ground diameter growth, and differences among different fertilization levels were significant, but chicken manure and potassium chloride exhibited no significant effect. According to YNCP growth and fertilizer cost, the best fertilization solution was 14 kg pig manure+1.5 kg calcium superphosphate per tree. The regression equation between pig manure (x₁), calcium superphosphate(x₂) and tree height (y_H) was y_H=1.016+0.031x₁+0.221x₂ (R²=0.835, P=0.000), and the regression equation between pig manure, calcium superphosphate and ground diameter (y_D) was y_D=26.193+0.991x₁+6.052x₂ (R²=0.832, P=0.000).

Conclusion Combined application of organic and inorganic fertilizers can significantly promote YNCP growth, and 14 kg pig manure + 1.5 kg calcium superphosphate per tree have the best promoting effect.