Effect of Soil Hydrothermal Regimes on the Performance of Safflower Planted on Different Dates

Abstract

AbstractSoil hydrothermal regimes which can enhance seed germination, seedling emergence and development so that the late planted safflower (Carthamus tinctorius L.) can be competitive in comparison to normally planted crop need to be studied and suitabily modified. Therefore, a split‐plot held experiment was conducted in Vertisols during 1984–85 and 1985–86 post‐rainy season to determine the influence of planting date (PD1: Oct. 20; PD2: Oct. 30; PD3: Nov. 10; PD4: Nov. 20; PDs: Nov. 30; PD6: Dec. 10; and PD7: Dec. 20), irrigation (I1: come‐up irrigation and I2: I1+ branching stage) and straw‐mulch (M0: No mulch and M1: paddy straw mulch at 10 t ha‐1) and the interaction on the growth and development of safflower (Cultivar, JSF‐7).Germination of safflower commenced earlier in October planting, but it was significantly higher in November and December plantings. Initiation of emergence and completion of germination required 153 and 307 cumulative degree days (CDD soil), respectively. Days to maturity decreased from 163 to 140 in 1984–85 and from 156 to 137 in 1985–86 with delay in planting from October to December. Height, number of branches, number of capsules, seed yield per plant and 1000 seed weight were significantly affected by the different treatments. Planting of safflower on October 30 and November 10 in both the seasons produced significantly higher seed yield than the other plantings. Branching stage irrigation (I2) and straw mulching significantly improved all the yield attributes and seed yield of safflower in both the seasons. The water use efficiency (WUE) was higher in early plantings than in the later plantings. Higher WUE was obtained under come‐up irrigation. Straw mulching increased the WUE, moderated the diurnal variations in soil temperature and provided a better thermostable regime more congenial for plant roots which resulted in increased safflower seed yield.