Polygenetic Vertisols of the Purna Valley of Central India

ICRISAT, India Soils:Yesterday, Today and Tomorrow

“…Climate change may further increase the threat to soil sustainability in poor countries because the cereal crop yields are predicted to decline in most tropical and sub-tropical regions under the future climatic scenarios 2 , and in countries which have a low capacity to adapt 3 . The impact of climate change in soils of tropical parts of the Indian subcontinent, in particular and globally, in general, has attracted the attention of soil researchers in recent years as indicated by degradation in soil physical, chemical and biological properties [4][5][6][7][8][9][10] . Amidst neo-tectonics and the global warming phenomenon, rising temperature and shrinking annual rainfall with erratic distribution pose perpetual threats for soils not only for the Indian subcontinent but also for soils of similar climatic conditions elsewhere 10 .…”

“…Amidst neo-tectonics and the global warming phenomenon, rising temperature and shrinking annual rainfall with erratic distribution pose perpetual threats for soils not only for the Indian subcontinent but also for soils of similar climatic conditions elsewhere 10 . In India, a change of climate has been recorded from humid to semi-arid in rainfed areas only during the Holocene period 9,11 . It is observed that the red and black soils as two major soil types of India under SAT environments, are gradually converted from non-calcareous to calcareous with the concomitant development of exchangeable sodium percentage (ESP) in the subsoils, which indicates a climatically controlled natural degradation 8,11 .…”

Effect of pH on Na induced Ca deficiency

“…Sodic and alkaline soils are found throughout the world but are of particular importance in India where there are approximately 73 M ha of deep Vertisols (Murthy et al, 1982), much of which is strongly sodic (with ESPs of up to 52%) and alkaline (with pHs of up to 9.0), with high soil solution Na/Ca molar ratios (up to 60) (Dubey, 1996;Pal et al, 2001). Bauxite residue, the waste material produced during alumina production by the Bayer process, is also highly sodic (ESP 100%) and alkaline (pH 12).…”

Natural Chemical Degradation of Soils in the Indian Semi-Arid Tropics and Remedial Measures

“…Although selected pedogenic processes such as laterization, hard setting, fragipan formation and claypan formation are hitherto considered as natural soil degradation processes as they lead to less desirable physical and chemical conditions, causing degradation of soils 7,8 , the majority of the information on soil degradation at national 9,10 , regional 11 or international level 12,13 has focused only on anthropogenic degradation. However, a few recent reports on major soil types (Indo-Gangetic Plains or IGP, red ferruginous and deep black soils) at the National Bureau of Soil Survey and Land Use Planning (NBSS&LUP, ICAR), Nagpur, India showed that the development of sodicity and accumulation of relatively higher amounts of exchangeable Mg (EMP) than that of exchangeable Ca (ECP) in soils are also a natural process of soil degradation in the SAT climatic conditions 1,3,[14][15][16][17][18][19][20] .…”