ABSTRACT
The evaluation of soil resources and assessment of soil related constraints is the only proper way to manage the soils for sustainable crop production. The database on soil properties particularly measurable, obtained through 106soil resource studies is important tool for practical purpose of assessing suitability of each soil unit for agricultural crops. Therefore, the present study was undertaken to evaluate the shrink- swell soils of Chandrabhaga valley of central India for various crops. Various geomorphological processes operating on different landforms and the typifying pedons representing various landforms were studied. Most of the soils formed in basaltic alluvium were deep dark brown to very dark gray in color, had very high clay content, calcareous in nature, imperfect to moderately drained, low saturated hydraulic conductivity (sHC) (0.01 to 27.4 mm hr−1). Lower values of sHC in some soils was due to higher exch. sodium percentage (>5) and low exch. Ca/Mg ratio (<1.5). The soils are neutral to strongly alkaline, non-saline with exchangeable sodium percent (ESP) well below 5% except in some irrigated soils. They have variable exchangeable Ca/Mg ratio (0.5 to 5.3) and exchangeable magnesium percentage (12.5 to 51.5). Although the thermal regime of the region is conducive for cropping throughout the year, the period of moisture availability (LGP) is quite variable from soil to soil. The exercise on land suitability evaluation indicated that soils have good potential for crop production because of their better rooting depth, high clay of smectitic nature associated with high cation exchange capacity (CEC) and plant available water capacity with a high base status. However, poor drainage appears to be the main parameter controlling the crop production in the area. The deep-rooted crops like cotton and pigeonpea can be successfully grown in well-developed Vertisols with sHC higher than 10 mm hr−1 while soybean, sorghum and groundnut can be grown on vertic intergrades with relatively higher sHC and better drainage. Thus the productivity of these soils is primarily governed by important parameters like sHC indicating that the determination of measured parameters in a particular crop-climatic-soil environment would be a prudent approach in the field of land evaluation instead of depending upon inferred parameters. sHC, ESP and Ca/Mg ratio can be regarded as the soil quality indices of Vertisols and associated vertic intergrades as they govern the productivity of these soils.
