Beneficial nanoparticles are at the leading edge of the rapidly developing field of nanotechnology. Nanotechnology applied to nanofertilizers could play a fundamental role in improving the availability of plant nutrients under unfavourable environmental conditions. To evaluate the effects of different levels of nitrogen fertilizer (0, 75, and 150 kg ha–1) and nanostructured micronutrients (Zn, Fe, Cu) on the seed yield of spring safflower, a study was carried out in the highland region of Baneh, Iran. Specific objectives were to assess the effects of combined application of nano-chelated micronutrients and nitrogen on safflower under rainfed conditions. Assessments of morphological traits revealed that application of nitrogen at the rate of 75 kg ha–1 significantly increased the plant height, canopy spread, stem diameter, and plant dry weight. Also, ground cover, canopy spread, capitulum diameter, and the number of the secondary branches were considerably affected by nano-chelated micronutrients, so the highest values were observed in the plants grown with the application of zinc and copper. Results showed that the effects of interaction of nitrogen and micronutrients were significant for the biological yield, seed number, 1000-seed weight, the percentage of unfilled seeds, and seed yield. A comparison of combined treatments showed that the best performance was recorded for plants grown with the application of N0-Zn, N75-Zn, and N150-Cu. The results of the present experiment agreed with the conclusion that utilization of nitrogen may affect the efficiency of micronutrients. Altogether, the results suggested that the application of intermediate levels of nitrogen fertilizers along with nano-chelated Zn can improve safflower production under rainfed condition.

Chickpea is one of the most important legume crops in the Mediterranean semiarid regions. Soils of these regions generally have free CaCO3, high pH and low organic matter, which reduce the availability of micronutrients and cause their deficiencies. In order to study the effects of integrated application of different level of elemental sulfur (0, 15, 30 kg·ha−1) and nano-chelated micronutrients (Zn, Fe, Mn) on growth and agro-morphological traits of chickpea (Cicer arietinum L.), a field experiment was conducted in the semiarid regions of the northwestern part of Iran. Evaluation of morphological traits showed that application of high level of sulfur significantly improved plant height, the number of primary branches and canopy width compared to the control. The longest growth period was recorded for plants grown by application of high level of sulfur and nano-chelated Zn fertilizer. The obtained data revealed that application of nano-chelated Zn fertilizer resulted in a significant increase in seed number per plant and seed weight compared to other nano-micronutrient fertilizers. Overall, the best growth performance and the highest seed yield were obtained from the integrated application of Zn and high level of sulfur. The findings showed that soil micronutrient deficiencies are partly due to high alkalinity of the soil, and application of sulfur beyond 15 kg·ha−1 can be an effective method to increase the efficacy of nanofertilizers. Integrated application of micronutrient and sulfur should be considered as an efficient agronomic management option for chickpea production systems in semiarid region.

Deficiencies of zinc, manganese and iron are common in calcareous soils of arid and semiarid regions due to their reduced solubility alkaline conditions. However, sustainable crop production is essential for growing population. Sulfur fertilizers can increase micronutrients availability by decreasing soil pH. In order to investigate the influence of nano-chelated essential metals (Zn, Mn, Fe) and sulfur application (zero and 40 kg ha-1) an experiment was carried out in Maragheh, northwest of Iran. Phenological development, morphological and agronomic traits significantly responded to both factors. Results revealed that application of sulfur fertilizer considerably increased morphological traits such as ground cover, stem diameter, plant height and capitulum diameter. Mean comparison between nano-chelated metal showed that the highest value for seed yield and yield components (number of the capitulum per plants, seed number per capitulum and seed weight) was achieved through the application of nano-chelated Zn. The best performance was related to combined application of sulfur and nano-chelated Zn which was followed by nano-chelated Fe. Seed oil content was only affected by nano-metals, so the highest value was obtained by application of nano-chelated Zn. Overall our finding revealed that integrated application of sulfur and essential metals, especially Zn, is required to grow safflower successfully on calcareous soils. The efficiency of nano-chelated fertilizers can be noticeably increased by balanced nutrient management in semi-arid regions.