Abstract:

Zanthoxylum schinifolium is a typical fertilizer-loving, shallow-rooted spice plant, which is highly dependent on soil fertilization for its ecological function and economic yield in desert soils. A structured fertilization program was used to analyze the effects of different fertilization levels on the photosynthetic metabolism capacity and yield traits of green peppercorns in rocky desertification areas, and to construct a fertilizer effect equation to solve for the economic yield and a step-by-step optimization method to obtain the optimum fertilization interval for the best economic yield. The results showed that among the indicators of ear traits, there were no significant difference in fruit stalk length and no significant difference in fruit number per ear among treatments. Fruit size was significantly different between treatments 6, 8 and 12 and treatments 1, 2, 7 and 13 (P<0.05). The number of pericarp gland points was significantly different (P<0.05) in treatment 13 and CK (treatment 1). Ear size differed significantly (P<0.05) from CK to treatments 8 and 12. The net photosynthetic rate (NPR) of leaves in the test area was not well fitted to the fertilizer response and was not predictive. The effect of NPK on the economic yield of Z. schinifolium was K₂O>N>P₂O₅, and there was a positive reciprocal effect between the test factors with the reciprocal effect of NP>NK>PK. The ternary quadratic economic yield function obtained, calculated by derivation, gave a maximum yield of 2.736 kg/plant. The optimum economic yield (1.515 kg/plant) was obtained with reference to the market fertilizer cost, and the optimal fertilizer ratio was 232.98 g/plant for urea (N), 166.64 g/plant for phosphorus (P₂O₅) and 297.38 g/plant for potassium. Yield traits under stony soil conditions are strongly influenced by structural fertilizer supply, and Z. schinifolium choose a priority strategy highly correlated with economic yield, with mediated compensation of photosynthetic metabolism as a secondary priority. Structural fertilizer interventions can affect the net photosynthetic rate of leaves and play a positive balancing role in adjusting ecological functioning, but unlike some deep-rooted plants (e.g. licorice), do not conform to the law of diminishing marginal compensation for fertilizer efficacy. With the intervention of ternary fertilizers, the fertilizer effect equation can be fitted better, and the optimal fertilizer formulation interval can be obtained to guide the ecological function of vegetation and economic crops for productive fertilizer program reference.

Key words: Z. schinifolium, yield traits, fertilization interval, nonlinear response, anabolism, rocky desert soil, structured fertilization, photosynthetic metabolism, economic yield, optimal fertilizer application rate