Effects of phosphorus and zinc application on the growth and oil ratio of safflower (Carthamus tinctorius L.) under calcareous soil conditions

In order to evaluate the effect of phosphorus and zinc fertilizer on the elements concentration, growth, and oil ratio of safflower           (Carthamus tinctorius L.) under calcareous soil conditions, this study was conducted at the farm of the Agricultural Research Station in     Qaragool, during the winter season of 2022-2023. A randomized complete block design (RCBD) with three replicates was used to carry out a factorial experiment. The factors examined included the factor P with three levels of phosphorus fertilizer (0, 100, 200) kg P2O5 ha-1 from the source of triple superphosphate and factor Zn with three levels of zinc spraying in concentrations of (0, 15, 30) kg Zn ha-1 from the source of zinc sulfate. The results of this investigation confirm that both levels of (200 kg P2O5 ha-1 + 30 kg Zn ha-1 and 100 kg P2O5 ha-1 + 30 kg Zn ha-1) have a significant impact on some characteristics of yield and its components of the plant, for example, plant height (141.667 cm), main branches plant-1 (30.000), number of heads plant-1 (95.667), number of seeds head-1 (19.000), weight of 100 seeds (3.757g), and seed yield (13.450 Mg ha-1). Moreover,     variance analysis showed that the interaction between different levels of phosphorus with zinc fertilizer has a significant effect on nutrient content in the rhizosphere soil, nutrient content in the seed, and the shoot of the safflower plant. Also, the oil content (42.660%) in the seed and fatty acids such as linoleic acid (65.620%) and linolenic acid (0.097%) in the seed oil of safflower are affected by the interaction between different levels of phosphorus and zinc fertilizer.