Effects of Potasium, mangnesum, iron, and zinc on yield and oil content of two cultivar of sunflower in Gonbad

Bearing in mind that over ninety percent of our country’s edible oil consumption is importedit is necessary that a great number of applied researches be carried out to achieve methods of increasing quantitative and qualitative yield of oil seed crops in general and sunflower in particular, because of its great adaptability, resistance to draught, short period of growth (85 – 110 days) and the possibility of planting it as a second crop after wheat and barley make the research on sunflower of great importance. Since nutritional elements are one of the essential factors in yield increase, the effects of N, P, K, Mg, S and trace elements (Zn, Fe, B) on yield and seed quality of sunflower (Golsheed and Record) were investigated. The experiment was carried out with nine fertilizer treatments and two varieties of sunflowers (Golsheed and Record) in a Randomized Complete Block Design arranged in a split-plot with three replications in Agricultural Experiment Station of Gonbad in 2000 and 2001. Before planting, a compound soil sample from the experiment site was taken. The common laboratory procedures were used to determine the chemical characteristics that are as follow: Fe ava = 2.6, Zn ava = 0.6, K ava = 350 and B ava = 20 mg kg – and#1633, % OC = 1.46, % TNV = 20 and pH = 8.1. Taking the results and field observation into account the following treatments were selected: and#1633– Common adopted dosages by local farmers (NP( and#1634– NPS 3 – NPK 4 – NPKMg 5 – NPKMgZn 6 – NPKMgFe 7 – NPKMgB and#1640– NPKMgZnFe 9 – NPKMgZnB Nitrogen from urea, phosphorus from triple super phosphate and potash from potassium sulfate were applied with the dosage of 100, 100 and 150 kg ha –1, respectively. Fe from seqostrene 138, sulfur and magnesium sulfate were applied with the dosages of 15, 500 and 75 kg ha –1, respectively. Spraying of Zinc sulfate and borate with the rate of 0.003 and 0.015 were applied in three stages, respectivelyone week before anthesis and with 15 days interval. After harvesting, seed and oil yield, protein content and the content of nutritional elements of the leaves (the forth leaf from the top flowering) and of the seed were determined using the common laboratory procedures. Results revealed that there is a significant difference (0.01) between two varietise for seed yield in the first year. In second year The fifth treatment (NPKMgZn) and first treatment (common adopted dosages by local farmers) had the highest and the lowest yield, respectively. and#1633and#1637Considering little variation of oil content, the oil yield was attributed to seed yield. The effect of fertilizer treatment on the number of grain per head was significant and the fifth treatment (NPKMgZn) had the highest number of grain per head .Year by variety intraction was significant for plant hieght. Effect of year by fertilizer intraction on seed yield was significant.these result reveals the suitable climatic condition of second year. Treatment five(NPKMgZn) had the highest seed