The effects of magnesium, iron, manganese and zinc fertilizers on the yield and quality of sunflower

摘要

This research was carried out during the 2000 and 2001 growing seasons with the aim of increasing the qualitative and quantitative yield of sunflower at the Zanjan Agricultural Research farm. A randomized complete block design (RCBD) experiment with 16 treatments and 3 replications was used to evaluate the effect of fertilizers, including magnesium, zinc, manganese and iron along with nitrogen, phosphorus and potassium, on improving the yield and quality of the sunflower crop. The experimental treatments included T_1=NPK; T_2=NPKMg; T_3=NPKMn; T_4=NPKZn; T_5=NPKFe; T_6= NPKMgMn; T_7=NPKMgZn; T_8=NPKMgFe; T_9= NPKMnZn; T_(10)=NPKMnFe; T_(11)=NPKZnFe; T_(12)=NPKMgZn; T_(13)=NPKMgMnFe; T_(14)=NPKMgZnFe; T_(15)=NPKMnZnFe; T_(16)= NPKMgMnZnFe. While nitrogen, phosphorus and potassium rates were the same for all the treatments, other fertilizers such as magnesium sulfate at 50 kg/ha, manganese sulfate at 60, zinc sulfate at 65 and iron sulfate at 120 kg/ha were banded each year before planting, according to the experimental design. In addition to the seed yield, a thousand seed index, percent oil and the total oil yield were determined at harvest 'The results of the two year trial showed that there were significant differences (at 5% level) in the seed yield between the different treatments. The T_8 (NPK+MgFe) treatment with a yield of 4634 kg/ha was statistically in class A, showing a 970 kg/ha yield increase (about 30%) compared with T_1 (NPK). While the control treatment (T_1) showed an oil content of 47.62%, T_(11) (NPKZnFe) gave an oil content of 50.24% (an increase of 5.5% above the control). There were also significant differences (at the 5% level) in the diameter of sunflower discs, thousand seed weight, plant height and stem diameter due to the experimental treatments. The highest values for the thousand seed weight and plant height were obtained with T_8 (NPKMgFe) and the largest disc diameter was obtained with T_9 (NPKMnZn). There were no significant differences in the protein content or the nutrient levels of the seeds between the various treatments. More research is needed in this respect, especially concerning the anion associating with the magnesium ion, as well as the role of the foliar application of micronutrients combined with the soil application of these elements.