International Journal of Agricultural Sciences

Rajeshwar Malavath ¹, S. Mani ²

Affiliations
1 Acharya N.G Ranga Agricultural University, A.P Water Management Project, Agricultural Research Station., Garikapadu, KRISHNA (A.P.), IN
2 Department of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, Tamil Nadu Agricultural University, COIMBATORE (T.N.), IN

Abstract

The present study was carried out to estimate the available water capacity of 246 soil samples collected from red lateritic soils of Dryland Agricultural Research Station, Chettinad, native red soils and application of transported black soils over the red native soils of Maize Research Station, Vagarai and black soils of Cotton Research Station, Veppanthattai of Tamil Nadu. The soils were analyzed for field capacity at 1/3 bar (33kpa) pressure and permanent wilting point at 15 bar (1500kPa) pressure in pressure plate apparatus besides, organic carbon and particle size distribution (soil texture) in surface and subsurface soils. In red lateritic soils the moisture retention at field capacity ranged from 13.2 to 20.5 and 13.8 to22.5 per cent, at permanent wilting point ranged from 5.4 to 10.9 and 4.9-11.6 per cent and available water capacity (moisture retained between 1/3 bar and 15 bar pressure) varied from 4.3 to 13.3 and 4.9 to 13.7 per cent. The moisture retention of application of transported black soils over native red soils varied from 29.2-30.4 and 19.8-22.7 per cent, at permanent wilting capacity varied from 14.8-16.9 and 7.6-9.2 per cent and the available water capacity varied from 13.6-15.5 and 11.9-14.1 per cent. The moisture retention of native red soils at field capacity varied from 16.2-19.4 and 16.2-18.5 per cent, at permanent wilting capacity varied from 5.4-7.6 and 4.9-7.8 per cent and the available water capacity varied from 10.2-11.6 and 11.3-11.9 per cent. The moisture retention of black soils at field capacity ranged from 30.8 to 39.7 and 32.4 to 40.8 per cent, at permanent wilting point 15.3 per cent to 22.9 and 16.9-24.6 per cent. The available water capacity varied from 13.5 per cent to 18.5 and 13.8-18.4 per cent in both the surface and sub-surface soils, respectively. The sub-surface soils of transported black soils over native red soils have high moisture retention capacity than native sub-surface soils. The available water capacity and maximum water holding capacity in all the soils were in the order of black soils>transported black soils over the native red soils>red soils>red lateritic soils. The soil parameters viz., organic carbon, sand silt and clay significantly influenced the field capacity of soils. The transported black soils over native red soils is beneficial for retaining the more soil moisture for sustaining crop growth particularly in rainfed situations under changing climate.

Keywords

Water Retention Characteristics, Red Lateritic Soils, Red Soils, Transported Black Soils over the Red Soils, Black Soils Soil Texture, Pressure Membrane Apparatus.

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Rajeshwar Malavath ¹, S. Mani ²

Affiliations
1 Department of Soil Science and Agricultural Chemistry, College of Agriculture, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad (Telangana), IN
2 Department of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute (T.N.A.U.), Coimbatore (T.N.), IN

Abstract

The study was carried out in the three new research stations of TNAU with varied soil types with an objective to characterize and classify the some red, red laterite and black soils in semi arid tropical region of Tamil Nadu in relation to pedogenesis. The red soils were developed on weathered granite-gneiss parent material at gently sloping lands. The red laterite soils were developed on weathered granite-gneiss over laterite parent material at gently sloping lands to moderately steep sloping lands whereas the black soils were formed at nearly level or plain topography on granitic gneiss parent material mixed with calcareous murram. The red soils and red laterite soils are relatively more weathered than black soils. The red and red laterite soil colour varying from dark red to light reddish brown and dark reddish brown to light reddish brown, the black soils colour varying from very dark gray to dark grayish brown under dry and moist conditions, respectively. The soils are shallow (27 cm) to very deep (>170 cm). The surface horizons exhibited mostly medium fine granular to weak sub angular blocky structures whereas in subsurface horizons shown medium fine granular to medium strong sub angular blocky structures in red and red laterite soil pedons. The black soil pedons had coarse strong angular blocky structure. The textural class of fine earth fraction was clayey (52.9 to 64.3%) in black soils, whereas in red and red laterite soil pedons it was coarse textured gravelly sandy loam and sandy clay loam in the surface horizons and sandy loam, sandy clay loam and sandy clay in sub-surface horizons (54.5 to 73.7% sand and 16.5 to 40.9% clay). The silt content in most of the pedons showed an irregular trend with soil depth. Bulk density increased with increasing depth. The moisture retention at field capacity (33 kpa), permanent wilting point (1500 kpa) and available water capacity were high in black soils. Based on the morphology, physical, physico-chemical and chemical properties, the soils were classified as per USDA soil taxonomy into four orders viz., vertisols, alfisols, entisols and inceptisols.

Keywords

Genesis, Characterization, Classification, Red Soil, Red Laterite, Black Soils, Semi Arid Tropical Region.

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