Reactivation of Christmas tree growth of Pseudotsuga menziesii (Mirb.) Franco by chemical fertilization

Abstract

The demand for Christmas trees has increased considerably in Mexico; where 1.6 to 2.0 million of them are sold annually. Pseudotsuga menziesii is a species with high commercial potential, due to the quality of its wood and its preference as a Christmas tree. The research was carried out at Huayacocotla, Veracruz, Mexico to assess the effects of nitrogen, phosphorus, potassium and micronutrients on growth of seedlings of P. menziesii, four years after its establishment. The sources and doses for the macronutrients were 0.0 and 16.0, 0.0 and 16.5, and 0.0 and 17.0 grams tree-1 of urea, calcium triple superphosphate, and potassium sulfate, respectively. The source for micronutrients was the commercial product Sagaquel combi® (0.0 and 3.0 mililiters tree-1). We conducted a completely randomized factorial experiment 24, with a total of 16 treatments fivefold replicated. It was determined that the nitrogen and micronutrients had no significant effects on the response variables since they were just slightly deficient. On the other hand, nutrition with phosphorus increased basal diameter; however, such increase was not significant. Potassium significantly increased needle biomass. The treatments that induced greater retention of needles were those that received nitrogen, phosphorus and potassium or a combination of them. Laboratory soil analyzes are likely to be more efficient than fertilization trials at detecting nutrient deficiencies. The deficient nutrients in the plantation are potassium, phosphorus, and nitrogen, although the deficiency of the latter is slight.