WILD LUPINE FOR BIOLOGICAL RECLAMATION OF SAND PITS

Abstract

Introduction. The experience of reclamation shows the possibility for growing pine stands of high productivity in the abandoned pits. This is possible if the measures for soil enrichment are taken. To reclaim the disturb lands it is necessary to combine the experience of co-use of phytomeliorants and organic fertilizers. The goal of the research is to assess the influence of wild lupine (Lupinus perennis L.) on the nutritional characteristics of sandy soil and on the growth of planted Scots pine (Pinus sylvestris L.) in the abandoned sand pits in order to elaborate the measures for improvement the efficiency of reclamation of the considered lands. Objects and methods of research. Scots pine plantations, established in the abandoned sand pits, were the object of the research. Establishment and viability of these plantations, their growth and physiological state of trees were the criteria of influence of phytomeliorants on the quality and growth of pine in plantations. To determine the photosynthetic rate, the methods of taxation and the conductometric method were used. The content of total chlorophyll in needles was defined with the photoelectrocolorimetric method. Transpiration was studied using the method of quick weighing. Results. The content of principle fertilizer elements in the vegetative organs of wild lupine was defined. The most positive effect of lupine on soil fertility is observed in the upper 10 сm soil horizon. This is determined with accumulation of phytomass influencing microclimatic and soil-ecological conditions on the surface of the abandoned pit. It particularly concerns the plots where nontraditional fertilizers were applied. The content of organic matter has boosted by 1 %. Thus, a poorly-humus soil has become one soil class better. The content of total nitrogen is up by 5 per cent. The soil with lupine is of higher content of total exchangeable bases (it particularly concerns the calcium cations) and degree of base saturation as well as it is defined by the increase in content macronutrients. As a fertilizer, lupine has a long-term effect due to its rapid propagation along the territory and increase of the area of plant cover. This contributes to enhancement of intensity of physiologic processes and improvement of Scots pine growth. Conclusion. Sowing and planting wild lupine in sandy soils contributes to improvement of hydrophysical and agrochemical characteristics of these soils, and mitigation of internal soil microclimate. Besides, it has a complex, and direct and indirect influence on the growth of Scots pine in plantations. As such, recommendations for forest plantations establishment on reclaim lands, disturbed as a result of extraction of nontoxic minerals, shall obligatory include phytomelioration measures such as sowing wild lupine. The efficiency of phyromeliorants will increase if organic fertilizers are applied in sandy soil.