Agrophysical soil indices in field rotations

In long-time stationary experiment of Federal Agricultural Scientific Center of North-East founded in 1976, study of agro-physical soil indices was done in eight-field crop rotations. Soil in experiment field was sod-podzolic light loam. Plots were arranged systematically with four replications; total plot area was 77 m2. In 2016, first sampling of soil was in May. This period had rather dry weather, sum of precipitation was only 54% of average monthly, and humidity was at level of 15.87-18.17%; available soil moisture was 16.51-24.19 mm. Density of soil structure was within optimal values, and after sowing of spring crops was about 1.17-1.24 g/cm3. Second soil sampling was in June. Precipitations in this period did not influenced plant development; crops were stunted and had weakly developed ear. Soil humidity was 16.62-19.00 %, available soil moisture counted as «satisfactory» at 21.66-25.13 mm level; soil was some decompacted - 1.11-1.18 g/cm3, what was link with its higher humidity. In 2017 studies was shown that at 17.57-19.10% soil humidity available soil moisture during seedling stage was counted as «satisfactory» and was at level of 21.93-25.57 mm in average for rotations. However, low air temperature in May delays its appearance. Density of soil structure was optimal - 1.23-1.29 g/cm3. Second time of sampling was in earing stage at July precipitations about 189% of perennial norm. Arable layer humidity was 18.45-19.75%. Available soil moisture was «satisfactory» - 27.00-30.80 mm. Soil density exceeds optimal value and was within 1.28-1.36 g/m3. Eight-field rotations with pure, occupied, green manure fallows and different saturation with intercrops did not have significant differences on basic soil agro-physical indices in years differed on meteorological conditions.