The Assessment of the MCIA

Meliorative condition of the area is assessed according to categories: good, satisfactory, and unsatisfactory; depth to ground water, and soil salinity. The area is assessed unsatisfactory by meliorative condition under the following criteria:

where hf, \h \ is the actual and acceptable depth to ground water; Sf [5] is the actual and acceptable degree of soil salinization; and Ecef [Ece] is the actual and acceptable soil conductivity. Acceptable values were established for different soil-climatic zones by the Ministry of melioration and water industry [1]. Under modern conditions, however, sufficiency of the water supply in irrigated areas depends on the quality of water and structure of the crops. Taking into account these factors according to the methods of Ikramov, R. [2] and actual observations, the acceptable depth to ground water was determined for irrigated areas of Uzbekistan (Table 19.1).

Assessment methods of MCIA, taking into account the directivity of its values, were developed to improve the conducting of the cadastre. The dynamics of values during the last 3-5 years is analyzed and assessment specified taking into account their "stability" or "instability" from past to modern times. Assessment categories of the meliorative process are suggested (good, satisfactory, and unsatisfactory), and it may be considered stable if MCIA meets the requirements of the criteria of these categories. The MCIA is considered unstable if the meliorative process does not meet requirements of the criteria or if it varies. A computer program is used to assess the MCIA taking into account directivity of value changes. Extra meliorative activities are not recommended on the areas with good and satisfactory MCIA.

Table 19.1 Zonal meaning of acceptable midvegetation depth of the bedding level of groundwater on irrigated area (for conducting cadastre of land reclamation condition of irrigated area)

Granulometric composition of the soil and the basement rock (in the layer up to 4 m)

Clay sand, sand

Loam, clay and layered

Genetic type of No. relief

Regions,

Midvegetation depth of groundwater occurrence (in m,) by mineralization

Climatic zones and Types of soil areas irrigation Less than Less than Note moistening zones covering system 1 g/1 1-3 g/1 3-5 g/1 5—10 g/1 1 g/1 1-3 g/1 3-5 g/1 5-10 g/1

Turan lowland the delta and the lower reaches of the Amudarya river Turan lowland the lower reach of the Amudarya river Turan lowland

4 Turan lowland foothills and intermontane region

5 Foothills and intermontane region

Desert zone, very dry K =0.12

Meadow, marsh Karakalpak flood-plain ASSR

Desert zone, very Outdated dry Ky=0.12 irrigated meadow

Khorezm region -

Desert zone, very Desert takyr Bukhara region 1.2-1.3 1.2-1.4 1.5-1.6 1.7-1.8 1.5-1.7 1.5-2.4 1.8-2.9 2.1-3.2 dry Ky=0.12 alkaline brown-grey

Desert zone, very Meadow and Surkhandarya 1.3-1.4 1.3-1.4 1.5-1.6 1.7-1.8 1.5-1.7 1.5-2.4 1.9-2.9 2.1-3.2 desert takyr, region

1.3-2.2 1.8-2.8 2.0-3.1 Minimal value of acceptable depth is used for chloride and sulphate-chloride types 1.5-2.3 1.8-2.8 2.0-3.2 of aeration zone salinization: Maximal value is used for chloride-sulphate and sulphate types of salinization dry K=0.12 semidesert zone, semidry K =0.12, 0.33

Sierozem

Desert zone, very Sierozem meadowSyrdarya region 1.0-1.1 1.0-1.3 1.4—1.5 1.6-1.7 1.2-1.6 1.2-2.1 1.7-2.6 2.0-3.0 dry Ky=0.12 and meadow marsh

Operational and capital activities on HMS are necessary on areas where the MCIA is unsatisfactory.

It is suggested to assess the MCIA using characteristics of critical meliorative regimes because in practice we deal with meliorative systems of different and very often nonoptimal characteristics. By critical meliorative regime, we mean a set of soil conditions, such as irrigation, washing, agrotechnology, drainage, which provide high fertility and maximal crops by large depth intervals LGW (lower than root-inhabited layer). The characteristics of critical meliorative regimes are based on meliorative process modeling and hydromeliorative system operation by watersalt balance of the area under crops, efficiency of the irrigating system, the coefficient of irrigation area, values II-O and water escape [2].

When assessing a meliorative condition, it is suggested to use data on the crop capacity of cotton and wheat. Categories for crop capacity of cotton are more than 32 c/ha, high 24-32 c/ha, low 16-24 c/ha, and very low fewer than 16 c/ha. Categories for crop capacity of winter wheat are more than 48 c/ha, high 36-48 c/ ha, low fewer than 24-36 c/ha, and very low fewer than 24 c/ha. If LGW depth and soil salinization are unsatisfactory, but the crop capacity is high then the final assessment of MCIA is considered satisfactory. At the next stage, we determine the factors which form the MCIA (with the help of analyses of main factors influencing on it by serial exclusion); and the reason and types of activities which must be done to guarantee meliorative well-being of the areas (Fig. 19.1).

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