Effect of Cover Crops, Organic and Chemical Fertilizer on the Quantitative and Qualitative Characteristics of Safflower (Carthamus tinctorius)

In order to study the weeds biomass and some characteristics of safflower in presence of cover crops under fertilizer systems, an experiment was done as factorial based on randomized complete block design with three replications at the Urmia University farm in 2013. Treatments included cultivation of cover crops (Red clover, Grass pea, Vetch, Bitter vetch) along the safflower rows and two control treatments (safflower planting with and without weeding) as a first factor and application of organic manure (cattle manure) and the different chemical fertilizer systems (high input, medium input and low input systems) as second factor. Results showed that the number of seeds per head affected by fertilizer systems, so it increased with use of nitrogen fertilizer. Also the minimum of 1000-seed weight of safflower was obtained at low input fertilizer system. The maximum grain yield (3431 kg.ha-1) and oil yield (1030 kg.ha-1) were obtained in the treatment without plant cover crops and high levels fertilizer consumption, respectively. Also, weed biomass was affected by cover crops and fertilizer systems. So, Vetch cover crop in low input fertilizer system, cause to reduction the dry matter of Field bindweed, Common cocklebur and Johnson grass as 74.36, 83.1, 82.22% in comparison with sole culture of safflower in high input fertilizer system. Generally, cultivation of Vetch and Bitter vetch as cover crop along the safflower rows had the most impact in suppressing weeds and reducing their biomass.