Results of the study of the growth of artificial meliorative plantations of black saxaul on heavy saline soils of the drained bottom of the Aral Sea

The article contains the results of the 6-year studies of the growth of black saxaul, planted on experimental plots with different soil cultivation and insertion of ameliorants on the drained bottom of the Aral Sea (DBAS). The impact of meliorative measures on the content of easily soluble salts in the soil and particularly toxic for plant growth salt of chlorine is defined in the article. During the first varient a significant decrease occurred (2.3-4.7 times). The greatest decrease in the chlorine content was remarked for all years of observation during the application of phosphogypsum in the dose of 15t/ha. Biometric measurements showed that the height of black saxaul planted in spring 2013 was the highest in variant III when phosphogypsum in the dose of 45t/ha was applied in the soil. The height of the plants in I variant, having relatively high survival, lagged behind from the other variants. Rank analysis of all the experimental variants showed that the results in variant I take the first three ranks, the best results are noticed on the plot with the appliance of phosphogypsum 15t/ha. On the plots with appliance of phosphogypsum and ash, variant II had the first rank with the dose of insertion 45t/ha + 22.5 t/ha. The most optimal method of soil cultivation for the heavy saline soils of the drained bottom of the Aral Sea with the use of ameliorants is the ridging at a depth of 20 cm, appliance of phosphogypsum 15t/ha, deepening at a depth of 20 cm and appliance of free-salined sand. This will allow to increase the survival and improve the protective stands of black saxaul on the drained bottom of the Aral Sea. Besides, it was revealed that the positive influence of ameliorants depended on favourable weather conditions (availability of wind to transport free-salined sand, precipitation and others) to a great extent. The survival of black saxaul on the control plots without the appliance of ameliorants was not lower, but, sometimes, even higher than on experimental plots and the content of toxic salts on control was reducing stably. Therefore, for the heavy soils on the drained bottom of the Aral Sea it is possible to tillage soil with furrows without the appliance of ameliorants a year before planting.