Response of Rainfed Sunflower (Helianthus annuus L.) to Nitrogen Rates and Plant Population in the Semi‐arid Savanna Region of Nigeria

Abstract

Field experiments were conducted during the wet seasons of 1991,1992 and 1993 at the Abubakar Tafawa Balewa University Farm, Bauchi (10 ° 22‘N, 09 ° 47‘E) to study the response of sunflower (Helianthus annaus L.) to N rates and plant population under rainfed conditions. Four N rates (0, 50, 100 and 150 kg N ha ‐1) and four plant populations (40000,80000,120000 and 160000 plants ha‐1) were factorially combined in a randomized complete block design with three replications. Leaf area index, shoot dry weight and seed yield (kg ha‐1) increased significantly with increasing N rates from 0 to 100 kg N ha‐1. The growth and yield parameters per plant decreased significantly with increasing plant populations from 40000 to 160000 plants ha‐1, but the seed yield (kg ha‐1) obtained at 80000 plants ha‐1 was significantly higher than all the other plant populations. The interactions of N x plant population confounded the main effect of each factor on the growth and yield of sunflower. The seed yield (3425 kg ha‐1) obtained from the use of 100 kg N ha‐1 at 80000 plants ha‐1 was significantly higher than those obtained from all other combinations of N x population and out‐yielded the main effects of 100 kg N ha‐1 and 80000 plants ha‐1 by 18 % and 25 %, respectively. The use of 100 kg N ha‐1 at 80000 plants ha‐1 is therefore recommended for maximum yield of sunflower in Bauchi.

Effect of Sowing Density on the Growth, Yield and Nutrient Uptake of Hybrid Sunflower (Helianthus annuus L.) in Rabi Season

“…This may be due to the sufficient of environmental conditions in wide spacing and less competition between plants as well as increase light penetration within plant canopy which increased assimilation rate and oil formation. These results are in a good line with those obtained by Yakout et al, (1992), Sharief (1998), Allam et al, (2003), Ruffo et al, (2003), Ali and Osman (2004), And Tenebe et al, (2008). The sowing density and different nutrient levels had exerted a significant positive influence on seed yield of sunflower.…”

Effect of different planting density of sunflower varieties on yield and yield attributing characters in rice-rice-sunflower cropping pattern

“…This may be due to better environmental conditions in wide spacing and less competition between plants as well as increased light penetration within plant canopy which increased assimilation rate and oil formation. These results are in agreement with the findings of some researchers(Beg et al, 2007;Tenebe et al, 2008). The increase in seed yield with increasing plant spacing might be attributed to an increase in head diameter and 1000 seed weight(Al-Thabet, 2006; Kazemeini et al, 2009).…”

“…Less plant competition for water, nutrients, and light in low plant population plots increased vegetative growth (Iqbal et al, 2007). There is more competition for water, nutrients, light, and other environmental factors between plants at high plant populations (Ali et al, 2011), resulting in reduced seed production (Beg et al, 2007) and less head diameter (Tenebe et al, 2008). The head diameter, thousand seed weight, and number of seeds per head were increased with increasing spacing (Al-thabet, 2006).…”

Effect of Plant Density on Growth and Yield of Two Sunflower Varieties

“…Through the combined data, the best treatment of plant density was 17500 Plants/fed when sown in 60 × 40 cm with one plant per hill (D1), which gave the highest score for all studied flowering and vegetative growth characters except plant height which had the highest score with 70000 plants/fed by space of culture 60 × 20 cm and two plants per hill (D4), that is my be due to the competition of two plants per hill and the shortage of space between hills. This point investigated before by Tenebe et al (1996), Sarmah et al (2000) and José et al (2004).…”