Effect of sowing schedules and crop geometry on photo-thermal energy utilization and productivity of Indian mustard (Brassica juncea) in Jammu region

A field experiment was conducted at the research farm of Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu and Kashmir during the winter (rabi) season of 2014–15 and 2015–16, to study the effect of different dates of sowing and planting geometries on photo-thermal energy utilization and productivity of Indian mustard [Brassica juncea (L.) Czernj.] var. ‘Giriraj’. Results revealed that the crop sown on 15 October showed significant increase in yield attributes, viz. siliquae/plant (276.5), seeds/siliqua (17.2), test weight (3.54) and seed yield (1.31 t/ha) besides concomitant increase in utilization of thermal energy envisaged through accumulated growing degree-days (1671.2 oC/day), helio-thermal units (9,336.6 oC/day/hr) and photo-thermal units (17,859.7 oC/day/hr) as well as heat-use efficiency (HUE) of seed (0.783 kg/ha/oC/day) and biological yield (3.35 kg/ha/oC/day) as compared to the other dates of sowing. Seed yield of Indian mustard declined progressively with advancement in sowing beyond 15 October. However, among the different planting geometries, the maximum average seed yield (1.14 t/ha) was observed at planting geometry of 30 cm × 10 cm, being at par with 30 cm × 20 cm spacing but significantly higher than the other planting geometries to the tune of 11.1, 17.2 and 23.7% over the spacings 30 cm × 30 cm, 45 cm × 15 cm and 45 cm × 30 cm, respectively. The heat-use efficiency of seed and biological yield was found higher in earlier-sown Indian mustard and decreased progressively with delayed sowing.