Prolonged effect of growth stimulants on cultivation of planting material of Koyama spruce Picea koraiensis Nakai

Koyama spruce (Picea koraiensis Nakai) is one of the main tree species in Primorsky Krai. Due to its rapid growth, light loving characteristics and good renewal on wood cutting and burned areas in combination with high technical qualities and decorative properties that distinguish it from other Far Eastern spruces, as well as positive experience of plants in various regions of Russia, this tree species is one of the promising coniferous species of the Russian Far East for forest restoration. Koyama spruce is valuable for landscaping cities and towns. However, its introduction is constrained by a number of factors, including a lack of quantity and a high cost of seed material. Use of growth stimulants accelerates production of high-quality planting material of spruce. The purpose of the research was to study the prolonged effect of pre-planting treatment of the root system of three-year-old saplings of Koyama spruce with growth stimulants Krezatsin (triethanolammonium salt of orthocresoxyacetic acid 475 g/l), Tsirkon (hydroxycinnamon acids) and Epin-Extra (epibrassinolide solution in alcohol 0.025 g/l) on morphometric parameters of one- and four-year-old seedlings. Three-year-old seedlings of Koyama spruce grown in the seedling section of the nursery were transplanted to nursery-garden on the area of 0.2 hectares. The seedlings were planted at a distance of 0.6×1 m. Before transplanting, their root system was placed for 0.5 hours in solutions of growth stimulants Krezatsin, Tsirkon and Epin-Extra (solution concentrations of 1 ml / 5 l and 1 ml / 10 l of water). Control saplings were not treated. At the end of the growing season at the end of the 1st and 4th years of growth, the saplings were measured in terms of stem height, height increase, and diameter of root collar. It was revealed that Krezatsin and Epin-Extra growth stimulants had a significant effect on both the growth of one- and four-year-old seedlings So, in the first year of growth, the height of seedlings exceeded the control by 6.3…16.2 %, the increase in height - by 27.5…55.5 %, the diameter of root collar - by 40…80 %; in the fourth year, the excess of seedlings to control was 29.9…45.4, respectively; 7.6…51.5 and 33.3…55.6 %. It was found that the concentration of solutions of 1 ml / 10 l was more effective.