Ecological-economically balanced functioning of combined drainage systems on heavy soils Novgorod region
The article deals with the ecological and economically balanced functioning of combined drainage systems on heavy soils of the Novgorod region. The water-air regime of the drained lands and the parameters influencing it (a drainage drain, a level of ground waters) is considered as an ecological indicator, and economic - increase of productivity of lands. The studies were carried out at the experimental experimental field, drained by closed drainage with backfilling of the drainage trench of the sand-gravel mixture to the arable horizon (control), two-tier drainage and a combination of with deep loosening. The analysis of the results of the study showed that the experimental combined drainage system was set aside 88 % more runoff compared with control; in the excessively wet growing season (25 % probability of precipitation), the system of two-tier drainage there was the lowest level of groundwater and soil moisture; the effect of deep loosening began to decrease by 3 year of operation of combined drainage, so it is recommended to carry out deep loosening on loamy soils every 3 years; from the ecological and economic point of view the most balanced option is the combined two-tier drainage.