Study on agrometeorological indices for soybean crop under different sowing dates in Chhattisgarh region of India

Field experiment on soybean was carried out during kharif season of 2011. The experiment was conducted with four dates of sowing as main plot (10, 20, 30 June and 10 July) and three soybean varieties (JS 97–52, JS 335 and JS 93–05) as sub-plot in split plot design with three replications. The heat units like growing degree days (GDDs), photo-thermal units (PTU) and Helio-thermal unit (HTU) values decreased with the delay in sowing under all the varieties. However, higher values of radiation use efficiency and heat use efficiency were recorded with variety JS 97–52. Based on the results it was concluded that heat use efficiency of soybean cv. JS- 97 52 and JS-335 were far better to utilize heat units under all the sowing dates as compared to JS-93 05.