Fertility of peat soils in Western Siberia

The smallest moisture capacity in medium-thick peat soil in a meter layer is 671,2 mm, which is 19,3 % more than that of low-power and 38,9 % peat-gley soil. During the formation of the first mowing of perennial grasses, the moisture reserves in the 0,5‑meter layer were always in the optimal range (0,7–0,9 HB). The lack of moisture during deep occurrence of groundwater (1,2–1,6 m) causes a decrease in the yield of the second mowing of perennial grasses by 46–89 % in peat-gley soil and 25–40 % in medium-power soil. The arable layer of peaty-gley soil contains 4,4 times more nitrates than the average power. Without fertilizing after 3 years, the amount of nitrate nitrogen in peaty-gley soil is reduced by 1,9 times, low- and medium-power soil – by 2,3–2,4 times. The amount of nitrate nitrogen is more than that of ammonia, in peat-gley soil 4 times, low-power – 3,5 times. Reserves of available phosphorus in the arable layer of peaty-gley soil are 2,5 times greater than in lowpower, and 3,1 times in average power. Without fertilizing after 4 years, in the arable layer of peaty-gley soil under perennial grasses, the content of available phosphorus decreased by 45,4 %, in low-power – by 20,5 %, in medium-power – by 15,8 %. The advantage in potassium reserves in the arable layer belongs to peaty-gley soil and is due to its high content in the underlying mineral peat. In peaty-gley soil, the decrease in potassium reserves down the profile is 1,6 times; in thin soil – 3,2 times; average power – 2,5 times. Hay productivity of perennial grasses on peaty-gleyic soil is respectively higher by 8.3 and 24,5 % than on low- and medium-power peaty soils. A crucial role in increasing the yield of herbs and gaining increases is played by the nutritional regime.