Appraisal of optimal sowing time based on heat indices and row spacing for summer guar [Cyamopsis tetragonoloba (L.) Taub.

Abstract

A field experiment was conducted during summer seasons of 2013 to 2015 on clayey soil of Junagadh (Gujarat) to ascertain proper time of sowing (4th week of January, 2nd week of February and 4th week of February) and spacing (30 x 15 cm, 45 x 15 cm and 60 x 15 cm) in relation to growth and yield of guar [Cyamopsis tetragonoloba (L.) Taub.]. The results revealed that sowing in 2nd week of February enhanced growth and yield attributes viz., plant height, pods per plant and test weight and ultimately gave higher seed yield (1387 kg/ha) and stalk yield (2846 kg/ha) with higher growing degree days (GDD), helio thermal units (HTU), photo thermal units (PTU) and heat use efficiency (HUE) as well as higher net returns (Rs. 42, 051/ha) and B: C ratio (2.29) over early (4th week of January) and late (4th week of February) sowing. The results further indicated that 45 x 15 cm spacing promoted growth and yield attributes viz., plant height, branches per plant, pods per plant and test weight compared to 30 x 15 cm and 60 x 15 cm, which reflected in higher seed yield (1272 kg/ha) and stalk yield (2680 kg/ha) along with higher net returns (Rs. 37, 154/ha) and B: C ratio (2.03) over 30 x 15 cm and 60 x 15 cm spacing. Therefore, sowing in 2nd week of February (when soil temperature >22.3oC at 5 cm and >23.9oC at 10 cm depth) and spacing of 45 x 15 cm could be appropriate for maximizing yield and monetary returns from summer guar under south Saurashtra agro-climatic conditions of Gujarat.