Soil Salinity, Sodicity, Waterlogging and Reclamation MCQs 2026

A common reason reclamation of salt-affected land fails is applying leaching water without adequate

1. A Seed certification label ✓
2. B Drainage outlet ✓
3. C Leaf wax coating ✓
4. D Harvest machinery ✓

Biosaline agriculture focuses on productive use of saline land and water by growing

1. A Salt-tolerant crops and forages ✓
2. B Only salt-sensitive beans ✓
3. C Only crops without roots ✓
4. D Only plants under zero irrigation ✓

Reuse of saline drainage water is safest when managed through blending, suitable irrigation scheduling and

1. A Ignoring soil salinity monitoring ✓
2. B Stopping drainage maintenance ✓
3. C Increasing waterlogging intentionally ✓
4. D Crop salt-tolerance selection ✓

The SI-compatible unit commonly used for soil electrical conductivity is

1. A kg/ha ✓
2. B cmol/kg only ✓
3. C dS/m ✓
4. D percent clay ✓

The term black alkali is commonly associated with sodic soils because sodium disperses organic matter forming dark

1. A Iron rust coatings only ✓
2. B Sodium humate stains ✓
3. C Gypsum crystals only ✓
4. D Calcium phosphate bands ✓

Compared with sodic soils, saline soils often have better permeability because soluble salts promote

1. A Flocculation of clay particles ✓
2. B Clay dispersion by sodium carbonate ✓
3. C Complete pore blockage ✓
4. D Cementation by humus only ✓

Arid and semi-arid climates favor soil salinity because evaporation often exceeds

1. A Soil texture and structure ✓
2. B Root respiration and photosynthesis ✓
3. C Seed size and seed rate ✓
4. D Rainfall and natural leaching ✓

In arid areas, a shallow water table within about one to two meters can promote salinization through

1. A Permanent freezing of groundwater ✓
2. B Complete absence of dissolved ions ✓
3. C Capillary rise and evaporation ✓
4. D Conversion of salts into humus ✓

Among the listed crops, the crop usually regarded as sensitive to salinity is

1. A Barley ✓
2. B Cotton ✓
3. C Bean ✓
4. D Sugar beet ✓

Raised-bed planting can help in waterlogged or saline fields by improving root-zone aeration and

1. A Exchangeable sodium accumulation only ✓
2. B Surface drainage around crop rows ✓
3. C Capillary rise from groundwater only ✓
4. D Soil pH above 11 ✓

During the early years after reclamation, a salt-affected field should preferably be planted with

1. A Salt-tolerant crops ✓
2. B Only the most salt-sensitive vegetables ✓
3. C No cover crops ever ✓
4. D Only deep-rooted forest trees ✓

Gypsum requirement estimates the amount of gypsum needed to replace a desired quantity of

1. A Available nitrate ✓
2. B Soil organic carbon ✓
3. C Plant chlorophyll ✓
4. D Exchangeable sodium ✓

Hydraulic conductivity of a sodic soil usually decreases because clay particles become

1. A Magnetized ✓
2. B Converted to sand ✓
3. C Dispersed ✓
4. D Sterilized ✓

Sodium adsorption ratio is mainly used as an index of the sodicity hazard of

1. A Dry seed lots ✓
2. B Irrigation water ✓
3. C Stored grain ✓
4. D Pesticide spray droplets only ✓

Exchangeable sodium percentage is calculated as exchangeable sodium divided by cation exchange capacity, multiplied by

1. A 100 ✓
2. B 10 ✓
3. C 1000 ✓
4. D 0.1 ✓

Salt-affected soils are commonly classified using ECe, pH and

1. A Leaf area index only ✓
2. B Seed weight only ✓
3. C Rainfall intensity only ✓
4. D ESP or SAR ✓

Specific ion toxicity in salt-affected soils is commonly caused by excessive sodium, chloride or

1. A Oxygen ✓
2. B Nitrogen gas ✓
3. C Boron ✓
4. D Silicon dioxide ✓

The first physiological effect of salinity on many crops is reduced water uptake due to

1. A Excess oxygen pressure ✓
2. B Osmotic stress ✓
3. C Absence of sunlight ✓
4. D Direct nitrogen fixation ✓

Brackish irrigation water is water containing appreciable amounts of

1. A Dissolved salts ✓
2. B Only beneficial microbes ✓
3. C Only suspended clay without ions ✓
4. D Only dissolved oxygen ✓

Flooding a saline field for leaching is effective only when the soil also has adequate

1. A Sodium carbonate crusting ✓
2. B Pesticide residues ✓
3. C Seed dormancy ✓
4. D Permeability and drainage ✓

Pyrite and other acid-forming amendments aid sodic soil reclamation by generating acidity that releases

1. A Nitrogen from air directly ✓
2. B Potassium from irrigation water only ✓
3. C Calcium from native lime ✓
4. D Chlorophyll from roots ✓

Elemental sulfur can help reclaim calcareous sodic soils because oxidation produces acid that dissolves

1. A Sodium chloride gas ✓
2. B Calcium carbonate ✓
3. C Nitrate fertilizers instantly ✓
4. D Plant cellulose directly ✓

Adding organic matter to sodic soils helps reclamation by improving aggregation and

1. A Water infiltration ✓
2. B Sodium carbonate production only ✓
3. C Soil crust cementation only ✓
4. D Permanent waterlogging ✓

Interceptor drains along canals are designed mainly to reduce

1. A Photosynthesis in nearby crops ✓
2. B Seed germination in nurseries ✓
3. C Wind erosion from dry ridges ✓
4. D Seepage moving toward adjoining fields ✓

Leaching requirement is the extra fraction of irrigation water needed to

1. A Raise soil pH above 10 ✓
2. B Increase crop residue burning ✓
3. C Control salt accumulation in the root zone ✓
4. D Stop evapotranspiration completely ✓

Open surface drains in irrigated fields are used primarily to remove

1. A Only available phosphorus ✓
2. B Excess surface and shallow subsurface water ✓
3. C Only crop seeds ✓
4. D Only atmospheric nitrogen ✓

Subsurface tile drainage is installed mainly to

1. A Lower the water table ✓
2. B Increase exchangeable sodium percentage ✓
3. C Stop all rainfall infiltration ✓
4. D Apply nitrogen fertilizer ✓

Rice tolerates flooded conditions better than many upland crops because its plants develop

1. A Deep woody taproots only ✓
2. B Salt glands on leaf margins only ✓
3. C No root respiration requirement ✓
4. D Aerenchyma for internal oxygen movement ✓

The high pH of sodic soils is largely associated with hydrolysis of

1. A Sodium carbonate ✓
2. B Calcium sulfate ✓
3. C Potassium nitrate ✓
4. D Ferric phosphate ✓

Irrigation water with high residual sodium carbonate tends to increase soil sodicity because it precipitates calcium and magnesium as

1. A Nitrates ✓
2. B Chlorides ✓
3. C Sulfates only ✓
4. D Carbonates ✓

Residual sodium carbonate in irrigation water evaluates the hazard caused by carbonate and bicarbonate reducing soluble

1. A Nitrogen and sulfur ✓
2. B Boron and zinc ✓
3. C Calcium and magnesium ✓
4. D Carbon dioxide and oxygen ✓

After applying gypsum to a sodic soil, the displaced sodium must be removed mainly by

1. A Foliar spraying of micronutrients ✓
2. B Leaching through the profile ✓
3. C Harvesting green fodder only ✓
4. D Keeping the field dry forever ✓

The primary reclamation practice for saline but non-sodic soils is

1. A Leaching with good quality water and drainage ✓
2. B Adding only urea fertilizer ✓
3. C Compacting the soil surface ✓
4. D Removing all crop residues ✓

Capillary rise from a shallow saline water table causes salinization by carrying salts toward the surface where water

1. A Freezes permanently ✓
2. B Turns into nitrogen ✓
3. C Becomes organic matter ✓
4. D Evaporates ✓

A common cause of waterlogging in canal-irrigated areas is seepage combined with

1. A Excessive slope and runoff only ✓
2. B Very deep groundwater always ✓
3. C Inadequate natural or artificial drainage ✓
4. D Absence of irrigation canals ✓

Waterlogging in agriculture means the crop root zone is saturated long enough to cause

1. A Excess oxygen around roots ✓
2. B Oxygen deficiency around roots ✓
3. C Complete absence of soil water ✓
4. D Instant phosphorus fixation only ✓

Effective drainage is essential in salinity reclamation because it removes

1. A Salt-laden percolation water from the soil profile ✓
2. B All clay minerals from the field ✓
3. C Only insects from plant roots ✓
4. D All organic matter from topsoil ✓

Leaching of saline soils means applying good quality water to move salts

1. A Into the seed bag ✓
2. B Only onto leaf surfaces ✓
3. C Back to the soil surface ✓
4. D Below the active root zone ✓

Gypsum improves a sodic soil because calcium from gypsum replaces exchangeable sodium and the sodium is then

1. A Converted into nitrogen gas ✓
2. B Changed into clay mineral permanently ✓
3. C Leached out with percolating water ✓
4. D Absorbed by chlorophyll molecules ✓

The amendment most commonly used for reclaiming sodic soils is

1. A Urea ✓
2. B Gypsum ✓
3. C Muriate of potash ✓
4. D Rock phosphate ✓

Poor infiltration and surface sealing in sodic soils are mainly caused by

1. A Dispersion of clay particles by sodium ✓
2. B Excess gypsum flocculation ✓
3. C High sand content only ✓
4. D Low soil pH from sulfuric acid ✓

A white crust on the soil surface in arid irrigated fields usually indicates accumulation of

1. A Humus only ✓
2. B Iron oxide only ✓
3. C Fresh clay minerals only ✓
4. D Soluble salts ✓

Sodium adsorption ratio of irrigation water is calculated from sodium relative to

1. A Nitrogen and phosphorus concentrations ✓
2. B Boron and chloride concentrations only ✓
3. C Calcium and magnesium concentrations ✓
4. D Carbon and sulfur contents ✓

A saline-sodic soil generally has both ECe greater than 4 dS/m and

1. A Organic carbon greater than 10 percent ✓
2. B ESP greater than 15 ✓
3. C pH less than 4.5 always ✓
4. D No exchangeable sodium ✓

A sodic soil is commonly characterized by ESP above 15 and soil pH usually

1. A Greater than 8.5 ✓
2. B Less than 5.0 ✓
3. C Exactly neutral ✓
4. D Controlled only by rainfall ✓

A typical saline soil has ECe greater than 4 dS/m, ESP less than 15 and pH usually

1. A Above 10.5 ✓
2. B Exactly 7.0 always ✓
3. C Below 4.0 always ✓
4. D Below 8.5 ✓

Soil sodicity is mainly a problem of excessive

1. A Nitrate nitrogen in soil solution ✓
2. B Calcium carbonate in parent material ✓
3. C Exchangeable sodium on the soil complex ✓
4. D Organic carbon in surface soil ✓

The most common laboratory measure used to assess soil salinity is

1. A Cation exchange capacity only ✓
2. B Electrical conductivity of the saturation extract ✓
3. C Permanent wilting percentage ✓
4. D Bulk density of dry soil ✓

Among common field crops, the crop generally considered relatively salt tolerant is

1. A Bean ✓
2. B Barley ✓
3. C Onion ✓
4. D Carrot ✓

Soil salinity refers to the presence in the root zone of excessive

1. A Soluble salts ✓
2. B Exchangeable aluminum only ✓
3. C Organic residues only ✓
4. D Clay minerals only ✓