The publication of this Handbook was supported by the Russian Federation

S.A. Balyuk, A.A. Nosonenko and E.N. Drozd (Ukraine)
Amelioration measures applied to soils include the following groups: 1) hydrotechnical – drainage 
systems and soil leaching to remove salts, 2) agricultural – crop rotation systems, fertilization 
systems and soil tillage systems including ameliorative deep ploughing and 3) chemical – chemical 
amelioration treatments of  irrigation waters and soils.
Drainage systems. A drainage network consists of  interconnected hydrotechnical constructions 
(drains, collectors, pumping stations, etc.) that serves to remove an excess of  groundwater beyond 
the irrigated area into a storage place [8, 21] and provides maintenance of  soil water and salt 
regimes that are favourable for growth and development of  crops.
Soil drains within an irrigated area can be horizontal, vertical or combined and joined (horizontal 
and vertical). Horizontal drains gather and direct the groundwater away from the ameliorated area, 
while collectors transport it to the storage place. In cases of  a thick upper layer of  water-resistant 
soil or sediment and a confined aquifer, it is advisable to install vertical drains, i.e., holes with 
filters at the entry and joints to direct the collected water into pipes. Depending on the geological 
situation, one drainage hole can service an area from 100 to 500 ha. Vertical drainage systems are 
used, as a rule, for performing three main tasks: 1) the use of  freshwater from confined aquifers for 
irrigation and simultaneous desalinization of  soils, 2) the prevention of  saline groundwater from 
rising towards the surface and triggering secondary salinization of  soils within irrigated areas and 
3) the replacement of  saline groundwaters by fresh ones.
There are several techniques of  purification and desalinization treatments of  drainage waters that 
have been developed with the aim of  improving the ameliorative state of  irrigated lands. These 
techniques include local water treatment facilities, which use sorbents and ion exchange resins, 
and biological water treatment systems using natural energy (evaporation, displacement by ice in 
winter, etc.).
Combined systems of  vertical and horizontal drainage improve the efficiency of  water removal. 
A  combination  of   horizontal  drains  and  rows  of   wells  that  allow  gravitational  water  flow  into 
a horizontal pipe allows the removal of  excessive water from the upper soil layer with a poor 
permeability.