Water retention characteristics of red lateritic soils, red soils and black soils of Tamil Nadu in relation to soil texture

Abstract

The present study was carried out to estimate the available water capacity of 246 soil samples collected from red lateritic\rsoils of Dryland Agricultural Research Station, Chettinad, native red soils and application of transported black soils over the red\rnative soils of Maize Research Station, Vagarai and black soils of Cotton Research Station, Veppanthattai of Tamil Nadu. The soils\rwere analyzed for field capacity at 1/3 bar (33kpa) pressure and permanent wilting point at 15 bar (1500kPa) pressure in pressure\rplate apparatus besides, organic carbon and particle size distribution (soil texture) in surface and subsurface soils. In red lateritic\rsoils 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\rfrom 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\rfrom 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\rfrom 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\rwater 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\r16.2-19.4 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\rcapacity 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\rand 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\rfrom 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\rtransported black soils over native red soils have high moisture retention capacity than native sub-surface soils. The available\rwater capacity and maximum water holding capacity in all the soils were in the order of black soils>transported black soils over the\rnative red soils> red soils > red lateritic soils. The soil parameters viz., organic carbon, sand silt and clay significantly influenced\rthe field capacity of soils. The transported black soils over native red soils is beneficial for retaining the more soil moisture for\rsustaining crop growth particularly in rainfed situations under changing climate.