Research on Optimized Fertilization for Filling Type Flue-cured Tobacco Based on Partial Least -squares Regression

This study constructed a quantitative fertilization model for high-quality filling flue-cured tobacco leaves and the reduce of environmental pollution and the leaf quality decline caused by over-fertilization. A mathematic model of flue-cured tobacco production and principal chemical components was established by the Partial Least-squares Regression (PLSR) fertilization function model through massive field experiment. The results showed that there was significant regression relationship between NPK fertilizers and flue-cured tobacco production and chemical components. First order term modulus showed the primary and secondary relationship between NPK fertilizers affecting flue-cured tobacco, reciprocation term and quadratic term modulus indicated the occurrence of the threshold value of NPK fertilizer proration. The application of NPK fertilizers showed the synergistic effects below the threshold value, whereas NPK fertilizer application produced the antagonistic effects beyond the threshold. For obtaining the max economic returns, the optimum fertilization was N:P:K=1:1.6:2.1. For improving flue-cured tobacco aroma, inflammability and safely smoking, the optimum fertilization was N:P:K=1:1.3:2.9.