~ 74 ~ Journal of Pharmacognosy and Phytochemistry 2018; 7(3): 74-80 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2018; 7(3): 74-80 Received: 11-03-2018 Accepted: 12-04-2018 Rajeshwar Malavath Dept. of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, TNAU, Coimbatore, Tamil Nadu, India S Mani Dept. of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, TNAU, Coimbatore, Tamil Nadu, India Correspondence Rajeshwar Malavath Dept. of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, TNAU, Coimbatore, Tamil Nadu, India Affect of application of black soils over a native red soils on soil physical and physico-chemical properties Rajeshwar Malavath and S Mani Abstract Field wise geo-referenced morphological, physico-chemical characteristics and nutrients status by application of applied black soils over native red soils of semi arid regions of Tamil Nadu, India were studied. The physiography of study area was nearly level to gently sloppy. The textural class of fine earth fraction was coarse textured gravelly sandy loam and sandy clay loam in the surface soils of native red soils and sandy clay loam in sub-surface horizons of applied black soils over native red soils, whereas clayey in surface layers of applied black soils. The clay content was ranged from17.4 to 19.6 percent in surface and 19.8 to 21.4 percent in subsurface soils of native soils. The sub surface horizons of applied black soils over native soils, clay content ranged from 21.1 to 25.8 percent. The surface soils exhibited weak medium fine granular structures in native soils whereas in subsurface soils of applied black soils over native soil shown weak to medium subangular blocky structures. The moisture retention at field capacity (33kpa) by application of applied black soils over native red soils varied from 29.2-30.4 and 19.8-22.7%, permanent wilting capacity (1500kpa) varied from 14.8-16.9 and 7.6-9.2%, available water capacity varied from 13.6-15.5 and 11.9-14.1% respectively in both the surface and sub surface soils. The moisture retention at field capacity varied from 16.2-19.4 and 16.2-18.5%, at permanent wilting capacity varied from 5.4-7.6 and 4.9-7.8% and the available water capacity varied from 10.2-11.6 and11.3-11.9% in both the surface and sub surface soils of native red soils respectively. The moisture retention at field capacity, permanent wilting point and available water capacity were high in sub surface soils of application of black soils over the native red soils at different soil water suctions than native surface and subsurface soils. Exchangeable bases in all the soils were in the order of Ca ++ >Mg ++ >Na + >K + on the exchangeable complex. The CaCO3 content of native red soils (5.5 to 7.8 and 6.0 to 9.0 g kg -1 ) and in applied black soils ranged from 21.0 to 42.0 and 6.5 to 11.8 g kg -1 in both the surface and sub surface soils respectively. Keywords: Application of black soils over native soils, morphological, physico-chemical characteristics Introduction Tamil Nadu being under a semi-arid tropical monsoon climate has a number of soil types which are found in all types of climates, occupying for 4.0 percent (12.99m.ha) of the country’s geographical area. Hence their management varies from place to place besides the crop variation effect. Maintaining soil in the state of high productivity on sustainable basis is important for meeting basic needs of the people. Systematic study of soils is important for scientific utilization of land resources for sustainable agriculture production. The black soils are made up of extremely fine clayey material. They are well known for their capacity to hold moisture. In addition, they are rich in soil nutrients, such as calcium carbonate, magnesium, potash and lime. They develop deep cracks during hot weather, which helps in the proper aeration of the soil. It is mainly applied to improve soil and moisture conservation, water holding capacity as well as increase the aeration and porosity of the soil for better root growth. The information available on the application of applied black soils over native red soil is meager. Knowledge of the application of black soils over native soils is necessary for proper appraisal of their productivity and potential use. Keeping this in view, field wise geo-referenced morphological, physical, physico-chemical characteristics and nutrients status by application of applied black soils over native red soils and native red soils was taken upfor better scientific utilization of lands by identifying the potentials and limitations and to suggest suitable crop plan and management options for higher productivity.