Plant height response of soybean (Glycine max L. Merrill) to soil temperature and moisture variations at different sowing depths under rainfed conditions

Abstract

A field experiment was conducted during Kharif 2024 at the Main Agricultural Research Station, UAS Dharwad, to study the Plant height response of soybean (Glycine max L. Merrill) to soil temperature and moisture variations at different sowing depths under rainfed conditions. The experiment was laid out in a Factorial Randomized Complete Block Design with three replications and twelve treatment combinations comprising three sowing windows (10 July, 5 August, and 9 September), two sowing depths (5 cm and 10 cm), and two moisture management practices (with and without mulch). Results revealed that soil thermal and moisture regimes significantly influenced germination, emergence, and vegetative growth. Early sowing on July 10 maintained higher soil temperature (25.10-24.50 °C) with relatively lower moisture, which favored rapid seedling emergence and taller plants (25.78-52.00 cm) compared to delayed sowings. Sowing at 5 cm depth resulted in higher plant height (21.47-47.69 cm) due to favorable root-zone temperature, while 10 cm sowing favored moisture retention but delayed elongation. Mulching moderated soil hydrothermal conditions, enhanced root activity, and improved plant height (21.02-47.24 cm). Interaction effects indicated July 10 sowing at 5 cm with mulch produced maximum plant height (26.51-52.73 cm). The study emphasizes that optimum sowing time, shallow placement, and mulching are critical for enhancing soybean growth and stability under rainfed ecosystems.