The Effect of Zeolite and Nitrogen on the Agronomic Traits of Sunflower (Helianthus annuus L. cv. Farrokh Cultivar) at Different Planting Dates

In an attempt to study the effect of different amounts of zeolite and nitrogen on the agronomic traits of sunflower at different planting dates, a factorial experiment with three replications was carried out in a randomized complete-block design in Qazvin Agricultural Research Station in 2011. The experiment factors included: three planting dates (D1: 5 May, D2: 20 May, and D3: 4 June, 2011), three levels of nitrogen (N1: 50 kg/ha, N2: 75 kg/ha, and N3: 100 kg/ha), and two levels of zeolite (Z1: 0 t/ha and Z2: 10 t/ha). Farrokh cultivar was planted in this design. The analyzed traits in the experiment included the economic yield of the seed, the biological yield, oil yield, and the harvest index. The results indicated that the highest seed yield (3188 kg/ha) belonged to the first planting date with 100 kg/ha nitrogen and 10 t/ha zeolite and the lowest seed yield (740 kg/ha) related to the third planting date with 50 kg/ha nitrogen in the absence of zeolite. The highest harvest index (22/96 %) was obtained from the first planting date.