Effects of irrigation and fertilization on mineral nutrients in Scots pine needles.

An attempt was made to maximize the biomass production of young pines in a field experiment by eliminating the main growth-limiting factors, i.e., water and mineral nutrients. There were three treat ments in addition to the control: irrigation, fertilization and irrigation plus fertilization. The pine needles were analyzed for their contents of macronutrients and most nitrogen was found in needles from fertilized plots. In fertilized plus irrigated plots the N-content was lower and not within the range for maximum growth. The effects of the treatments on vegetation are also described.