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WATER-LOGGED SOILS, , ——, , Water-logged) or wetland soils can be defined as soils whose developmen,, properties are strongly influenced by temporary oF PETMAN SAlUFAtion in the ‘, The water-logging of the surfacial horwons brings about yy ', , ary chemical and physical changes to take place,, TYPES OF WATER-LOGGING, , Water-logging is following types *, (1) Riverine food water-logging. In the raimy season, flood may come we, river having excess flood water, Ne, , And, per, , part of the soils ducyy, &, , conditions for tempor, , nearby land from the, (2) Oceanic Mood water-logging. Ocean water spreads in the neraby land ana, i Ang, , causes water-logging., (3) Seasonal water-logging. Run off water accumulates in the lowlands ans, , depressions in the rainy season., (4) Perennial water-logging. Deep water, swamp ete, get rain water, run off y ater, and seepage water from canal causing perennial water-logging,, (5) Sub-soil water-logging. High water table in the rainy reason is normalh, unsuitable for root growth. :, FACTORS AFFECTING FORMATION OF WATER-LOGGED SOILS, , (i) Climatological factor. Due to high rainfall water accumulates on the sol, , surface., (ii) Flood. Flood water is usually causing water-logged situation in the field, , (iii) Seepage from canal. Ground water levels ave closer to the surface due to, , seepage from canal., (iv) Land shape. Saucer shaped land gets water from highlands which results ne, , water-logging., (v) Uncontrolled and unwanted irrigation, Excess irrigation may, , accumulation of water on the soil surface., (vi) Drainage. Poor drainage systems is responsible for water-logging in the, , CHARACTERISATION OF WET LAND SOILS, , The following are the classes of depth to the wet state :, Class 1: not wet above a depth of 400 cm,, Class 2: not wet above a depth of 100 cm., , field., , Scanned with CamScanner
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Claas J: not wet above a depth of 50 em, Clasa d: not wet above a depth of 25 em, «are based on soils that are not irrigated, , ption, moreover, the duration of the wet ot, state is taken into account TP, , se class, , In the desert, Juravion of the wet state are :, , cjasees ofd, Class a: wet less than one-twelfth of the tim, e, Class b : wet less than one-twelfth to one-fourth of the t, Clase ¢: wet less than one-fourth to one-half of th a ime, = we, Class d : wet more than one-half of the ime ame, Most wetland soils would belong to class 4, but under certain condit ', conditions clams 3 clase, , yand class | would come under deep water and floating rices, , CONSTRAINTS ASSOCIATED WITH EXCESS WATER, , Flooding with consequent crop submergence is a problem in many of th ‘, ands. Detrimental effects of water-logging are discussed any of the lower lying, , wetl, ay hierar depth. Lowland areas are usually flooded to depths of shout 3, (shallow rainfed lowland, and medium-deep) and the limitations to 7 E = =, associated with extensively low reduction potentiala and partly cn Ee, artly because of low, , phosphorus availability., , In the ‘deepwater’ (flooding to depths of 50 to 100 cm) and ‘very deepwar, floating’ (water depth more than 100 cm) areas, the principal problem « jen * rela, ys the tendency for the rice crop to be submerged for periods of upto 10 d Scaesliome, , (2) Poor aeration. Due to water-logging, a part of the soil air m, atmosphere as it is displaced by the incoming water. Inadequate supply of, retards or ceases plant growth as the accumulated carbondioxide hampers, the plant roots. Poor.aeration results in the development of toun and ot, substances. Only rice plants can survive poor aeration due to water-logging, , (3) Soil structure. Continuous water stagnation destroys the seal s, makes the soil compact. ., , (4) Soil temperature. Water-logging lowers down the sotl temperature, have a higher specific heat than dry soils. Consequently, a moist *, temperature than dry soil. Low temperature affects the micr, consequently lowered the rate of nitrogen-fixation., , : (6) Soil pH. There are reversible pH change of the fl, , in acid soils and decrease in alkaline soils. undoubtedly p, , . (6) Availability of nutrients. Nifrogen. Nitrogen deficiency 1s exte, , ater-logged soils. Due to lower temperature and reduced condition, muners, organic N is affected., , : Phosphorus. The inorganic forms of P a, , than in upland soils. An experiment 8, , ses P absorption by 28-70%., , Seria K response is apparent in many low, , omeentration of lowland preparation may considera A, e"* and Mace K because of displacement of exchangeable, , Sulph in the soil solution., ur. Sulphur deficiency has been re, , , , , , , , tructure and, , » Movrat souls, , has lower, , , , y whch, , , , oorganism 3ct, coded soils, pH tends to increase, His alter towards normal, , rmely co, , , , , , , at higher levels, , re usually present, f the soul by foeding, , howed that reduction ©, , , , , , lowland sails. Flooding and p, , derably increase the aot, K by the large amour, , ported from many lowland aress, , , , Scanned with CamScanner
