2. The algorithm of decision making sequence is developed, which enables the
water user to determine the optimal irrigation norms and irrigation regimes on the basis
of resource and economic assessment of the options of paid water use.
3. To determine the optimal values of irrigation norms, depending on the
economic conditions of a particular consumer, the conditions of the forecast year and
the value of the payment for water, simulation and optimization models of the functions
of additional net profit from irrigation for the main crops (winter wheat, alfalfa, sugar
beet, corn on grain and silage). It has been established that with the increase of the
water tariff the optimal value of irrigation norms decreases, the value of additional net
profit from irrigation decreases, it is necessary to use water-saving irrigation regimes.
4. It is confirmed that the optimal irrigation rates increase the additional net profit
from irrigation by 5-15%. At the same time, due to the reduction of irrigation norms to
30%, anthropogenic loading on soils decreases and the minimum level of water
infiltration in lower horizons is ensured.
5. It is proposed to use a multilayer model of moisture transfer on theoretical
principles of the thermodynamic approach, which provides operational control of soil
moisture during irrigation with high accuracy on the basis of adaptation of model
parameters to specific field conditions.
6. The principle of introducing an additional coefficient K in the transition from
the meter calculated soil layer to a layer of 0.5 m capacity is confirmed, which makes
it possible to use it efficiently in the balance method of calculating the soil moisture
dynamics when applying water-saving irrigation regimes. During the pilot-production
check on objects in the Kherson region, it was established that the coincidence of the
calculated values of soil moisture with actual measurements is quite satisfactory for
using the coefficient K in practice (the average deviation of 5-6% of HB).
7. The conducted complex of field observations and laboratory hydrophysical
investigations made it possible to identify the parameters of the multilayered
mathematical models of moisture transfer (the main hydrophysical characteristics, the
coefficient of moisture transfer) for operative management of irrigation in accordance
with the soil conditions of southern Ukraine (dark chestnut medium salinized and
chernozems of southern solonets).
8. The results of hydrophysical research, obtained on the basis of the method used,
illustrate the high information ability of the model for assessing the degree of soil
heterogeneity, the directions of change and the processes of soil interaction with the
flow of moisture. Comparison of the calculated and predicted values of soil moisture
(relative error does not exceed 5%) confirms the reliability and high efficiency of the
multi-layer model in the operational management of irrigation.
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