Impact of Plant Densities and Phosphate Fertilizer Types on Growth, Yield, Yield Components and Associated Weeds of Chickpea

A field experiment was conducted during the spring 2024 growing season at the Field Crops Farm of the College of Agricultural Engineering Sciences, University of Duhok, situated between longitude 42.87 W, latitude 36.86 N and altitude 583 meters, it is about 15 km from Duhok city. The objective was to critically evaluate the individual and combined effects of different plant densities and phosphate fertilizer types on the growth, productivity and associated weed plants of chickpea under rain-fed conditions. The factorial experiment was implemented using a randomized complete block design (RCBD) with three replications. The first factor included three plant densities (26.66, 33.33, and 44.44 plants.m-²), and the second factor included four fertilizer treatments: biofertilizer (20 kg .ha⁻¹), diammonium phosphate (DAP) (120 kg .ha⁻¹), triple superphosphate (TSP) (160 kg .ha⁻¹), and a check treatment. The results demonstrated that plant density had a comparatively limited effect on vegetative growth traits, while the type of fertilizer was a significant factor that influenced both development and productivity. The highest seed yield of 2637.96 kg. ha-1 was notably achieved by combining the highest plant density (44.44 plants. m-²) with TSP fertilizer. This superior treatment also consistently enhanced other crucial yield components, including the number of pods per plant, seeds per pod, 100-seed weight, and the biological yield. Furthermore, thirteen weed species, predominantly broadleaf types from six families, were recorded. The high-plant density in conjunction with TSP effectively suppressed weed emergence and significantly reduced weed dry biomass. In conclusion, the integration of a high plant density with Triple Super Phosphate fertilization provided the optimal agronomic strategy by synergistically enhancing crop growth, maximizing seed yield, and significantly improving competitiveness against weeds. This integrated approach is highly recommended for sustainable rain-fed chickpea production in the Duhok region and similar agro-climatic zones.