Subsoiling and crop rotation improve root growth of Bt-cotton in Vertisols

Soil compaction is a major physical constraint in cotton production. At present, no information is available on the effects of compaction on the root growth and root anatomy of cotton ( Gossypium hirsutum L.). Therefore, we studied the effects of subsoiling (shallow (SSS) and deep (DSS)) and crop rotation (pigeon pea ( Cajanus cajan ) – cotton (PCR) and radish ( Raphanus sativus ) – cotton (RCR)) on the root growth of cotton in deep Vertisols during 2017–19. Subsoiling significantly increased the shoot and root length. The root-to-shoot ratio was maximum in DSS (33%), followed by PCR (29%) at the vegetative stage. Scanning electron microscopy analysis of the roots indicated a large number of pores and less contraction of xylem and phloem in the sub-soiled and rotation treatments than in the control. Furthermore, the SEM-EDAX spectra indicated a greater abundance of major, secondary and micronutrients in subsoiling and crop rotations compared to the control treatment.