| Studies are dedicated to: development of set of measures
on water use improvement and soil salinity prevention on base
of increasing lands' drainability and leaching by constructing
closed horizontal drainage; definition of reclamation efficiency,
capability of this drainage type on hardly reclaimed soils
with high gypsum content in Central Fergana; scientific background
of set of measures on water use improvement and soil water-salt
regimes management.
Natural-economic conditions of experimental production
plot are typical for the most part of Central Fergana. It is located in the plain salt accumulation zone.
Climate is continental. Soils are hardly reclaimed with gypsum
content.
Experimental production plot net area - 80.7 ha. Irrigation
network - concrete flumes. Water intake from Big Andijan Canal,
water salinity degree - 0.5-0.9 g/l. Drainage is closed horizontal,
specific length - 40 m/ha, depth - 2.3-3 m.
Experimental plot is equipped with observation wells
and piezometers.
Field studies and observations of shifting of moister,
salts and measurement of all elements of aeration zone water-salt
balances, ground water, and irrigated area are carried out.
Above mentioned studies show that under closed horizontal
drainage operation and keeping optimal reclamation regime
following achievements can be:
-
reduction
of leaching regime norm from 1.43 to 1.05-1.10 that allows
to reduce annual water consumption norm on 10-15%;
-
ground
water desalinization on average over plot from 15 to 5 g/l;
-
drainage
flow desalinization on average over the plot from 5-10 to
2-4 g/l;
-
lands'
desalinization.
Cotton crop yield capacity substantially increased:
from 0.7-0.9 t/ha (1978) to 2.83 t/ha (1986)
Water productivity increased from 10000 to 3500-3900
m3/t. |
