Evaluate the effects of nitrogen fertilizers on rapeseed (Brassica napus L.) in term of auxiliary materials application

Background and objectives Nitrogen is one of the limiting factors for crop production in the world. However, a large percentage of the fertilizer used in the leaching and evaporation loss, need more material to help illustrate the effect of nitrogen fertilizers better. Studies have demonstrated various sources of nitrogen have a significant effect on its performance. Some researchers has reported the influence of ammonium absorption in plants. Application of superabsorbent materials can increase root surface and dry weigh 27 percent compare to the control. In this study, zeolite, super absorbent polymer clay as an effective material for reducing leaching and gelatin capsules as a barrier to reduce evaporation and leaching of fertilizers and nitrogen partly urea, ammonium sulfate, potassium Nitrate were compared.
Materials and methods To improve the effect of nitrogen fertilizers on the yield of oilseed rape, factorial experiment in a randomized complete block design with three replications was conducted as a pot in Tarbiat Modarres University research. Treatments were auxiliary materials in six levels (control levels, 8 and 4 mL gelatin capsules, zeolite (8 ton ha-1), super absorbent polymer (100 kg ha-1) and clay (to the extent that the clay soil Level 25% required) and without application auxiliary materials. And chemical fertilizers in four levels (urea, potassium nitrate and ammonium sulfate, respectively. The amount of each chemical fertilizers based on the delivery of 40 kg N ha for each pot was calculated in two steps by installments. All treatments were applied to the soil.
Results In the present experiment there was no significant difference in the number of seeds per plant between different levels of fertilizers in terms of the on use of auxiliary materials. The results showed that the use of gelatin capsules plus urea and the use of clay without the use of fertilizers had the highest and lowest yield respectively, with the1.6 grams difference. The use of gelatin capsules and clay in terms of urea were found highest and lowest percentage of oil, respectively, with 8.8% difference between. Zeolites and clay with 0.211 grams difference, urea and potassium nitrate with 0.17 grams of oil were the highest and lowest oil yield. It was also found urea fertilizer with zeolite or clay could increase SPAD index values relative to control.
Conclusion The results of this experiment showed that the use of these substances, especially gelatin capsules, can help to increase the impact of nitrogen fertilizers and yield, especially rapeseed oil to improve performance.