FULL-LENGTH RESEARCH ARTICLE Crack Formation in a Swell–Shrink Soil Under Various Managements D. K. Painuli 1 • M. Mohanty 2 • Nishant K. Sinha 2 • A. K. Misra 3 Received: 6 June 2015 / Accepted: 15 November 2016 Ó NAAS (National Academy of Agricultural Sciences) 2016 Abstract Swell–shrink soils generate wide and deep cracks, generally considered undesirable for crop husbandry. However, there is a lack of information about the management options available to reduce formation of wide and deep cracks in such soil. Therefore, the present study was conducted on an Entic Chromusterts. The results revealed that width (mm) and depth (mm) were 7 and 23, respectively, for initial soil wetness by weight 43% compared to their negligible values for initial wetness 14%, at bulk density 1.15 g cm -3 , and these two parameters were 7 and 27 mm, respectively, compared to 6 and 19 mm at bulk density 1.02 g cm -3 . Thus excessive wetness and higher compaction generated wide and deep cracks and should be avoided. Incorporation @10 t ha -1 of organic matter and gypsum in the soil reduced width and depth of the cracks and may be practiced; temperature beyond 35 °C generated narrow and shallow cracks. These management options should, however, be adapted for field application as per local needs and available resources. Keywords Compaction Á Drying temperature Á Initial soil wetness Á Soybean straw Á Wetting and drying cycle Introduction Swell–shrink soils are associated with high clay content and predominantly smectitic type of clays. Wide crack, extending continuous deep into the profile, is the major structural feature of the vertisols. These soils are believed to have developed in alluvium derived from Deccan trap basalt [19]. Review on the mineralogy of vertisols of India indicates that these soils are dominated by the beidellite– nontronite (smectite group minerals)-type minerals with subordinate amount of kaolinite, mica, and chlorite [3, 20]. Vertisols are also characterize with high contains of pedogenic and non-pedogenic calcium carbonate, irrespective of the environment to which they belong. The non-pedogenic calcium carbonate is part of the parent materials, whereas dissolution of non-pedogenic calcium carbonate and recrystallization of dissolved Ca 2? ions are responsible for the pedogenic calcium carbonate. Dissolu- tion and recrystallization of Ca 2? ion are the prime chemical reactions of the pedogenesis of these vertisols, which modifies pH, exchangeable Ca and Mg, and induces sodicity and most importantly hydroxyl interlaying in the smectite interlayers [26]. The presence of high amounts of highly active clay minerals such as smectites promotes the formation of cracks. A high plasticity index and low shrinkage limit indicate high potential for shrinkage and swelling [16]. Vertisols cover 335 million hectares out of a total earth land area of 14.8 billion hectares (2.3%). The largest areas covered with vertisols are in eastern Australia, India, Sudan–Ethiopia and Argentina–Uruguay [11]. Smaller areas of vertisols are found in various countries (e.g., China, Israel, Mexico, Spain, Tunisia, and USA). However, vertisols are very hard and crack when dry and are very sticky when wet. The extent and rate of cracking is & Nishant K. Sinha nishant.sinha76211@gmail.com 1 Central Arid Zone Research Institute, Jodhpur 342 003, India 2 Division of Soil Physics, ICAR-IISS, Indian Institute of Soil Science (ICAR), Bhopal, MP 462 038, India 3 Division of Soil Physics, Indian Institute of Soil Science, Berasia Road, Bhopal 462 038, India 123 Agric Res DOI 10.1007/s40003-016-0241-7