Study the effect of living mulch on phenological characteristics and quantitative and qualitative yield of sunflower cultivar

The purpose of this study was to determine the effect of fenugreek planting as a living mutch on the phenology, grain quality and yield of sunflower cultivars and to determine the most appropriate time for planting of sunflower. 

This experiment was done in 2016-17 growth season at Razi University. The experiment was conducted as split plot based on randomized complete block design. First factor was the sowing fenugreek at four levels (control (without living mulch), 15 days before sowing of sunflower, simultaneous sowing with sunflower, 15 days after sowing of sunflower) and the second factor was three sunflower cultivars (Progress, Farrokh, Lakomka). 

Planting of fenugreek as living mulch pre-sunflower led to a decrease in the quantitative and qualitative yield of sunflower. In 15 days before sunflower condition, grain, oil and protein yields of sunflower,were 38.5%, 37.9% and 43.6% lower than control treatment, respectively. In addition, the phenological stages of sunflower growth was delayed in pre-sunflower sowing conditions. So that the occurrence of staring, flowering, head formation and physiological maturity were 69.8, 21.8, 24.5 and 82.6 days, respectively (4.4, 1.1, 1 and 3 day) more than control conditions. However, planting of living mulch simultaneous and 15 days after sunflower had a positive effect on the quantitative and qualitative yield of sunflower grains. Grain, oil and protein yields of sunflower were 39.4%, 36.4% and 43.3% higher than control, respectively. These values were 25.5%, 26.7% and 23.5% after sunflower planting, respectively. Flowering and head formation stages in simultaneous planting conditions were 20.8 and 47.1 °C (0.7 and 1.4 days, respectively) and in post-sunflower sowing conditions were 42.3 and 122.6, respectively. Day growth rates were lower (1.8 and 4.6 days) than control conditions. Among sunflower cultivars, the occurrence of different phenological stages was higher for Progress cultivar than for Farrokh and Lakomka cultivars. Farrokh had the highest oil content (36%). The highest grain yield (3426 kg.ha-1), oil yield (1203 kg.ha-1) and protein yield (536 kg.ha-1) were allocated to Lacomka cultivar. 

It seems that competition between fenugreek plants and young sunflower plants seems to lead to poor vegetative growth and delay the time of phenological growth stages of sunflower by early sowing of mulch. These results confirm the importance of selecting the appropriate cultivar and minimizing competition by choosing the optimal planting time of living mulch, which gives the pottage-assisted effect a competitive advantage.