Effects of urea integration with manure and two types of compost (municipal waste and sewage sludge) on concentrations of micronutrients and sodium in wheat leaf, stem and seed

Due to lack of organic matter in most soils of Iran, use of different organic fertilizers in soil is very important for improving soil fertility, increasing water and nutrient storage capacity in soil, increasing water infiltration, reducing soil erosion and improving plant growth and yield. However, these fertilizers alone cannot provide all the requirements of plants for different nutrients and are not sufficiently available to farmers everywhere. On the other hand, high consumptions of chemical fertilizers cause environmental pollution and increased agricultural production costs. So, in order to increase effectiveness of organic and chemical fertilizers and to achieve sustainable agriculture, integrated application of organic and chemical fertilizers is recommended. The deficiencies of micronutrients in the most agricultural soils often reduce the yield and quality of wheat. Therefore, the appropriate concentrations of these nutrients in wheat are important not only for the optimum yield of the wheat plant and its quality improvement but also for the health of humans and animals. In order to improve micronutrients nutrition of wheat and its quality the integrated management of soil fertility is essential.

This research was carried out to study the effects of urea combining with farmyard manure (FYM), municipal solid waste compost (MSWC) and municipal sewage sludge compost (MSSC) on concentrations of micronutrients and sodium in seed, leaf and stem of wheat. The experiment was done in a randomized complete blocks design with 15 treatments and three replications under field conditions at Khalatposhan Agricultural Research Station, University of Tabriz, Tabriz, Iran. The treatments included were: 1) control, 2) 150 kg urea/ha, 3) 300 kg urea/ha, 4) 30 ton MSWC/ha, 5) 30 ton MSWC/ha + 150 kg urea/ha, 6) 60 ton MSWC/ha, 7) 60 ton MSWC/ha + 150 kg urea/ha, 8) 30 ton MSSC/ha, 9) 30 ton MSSC/ha + 150 kg urea/ha, 10) 60 ton MSSC/ha, 11) 60 ton MSSC/ha + 150 kg urea/ha, 12) 30 ton FYM/ha, 13) 30 ton FYM/ha + 150 kg urea/ha, 14) 60 ton FYM/ha, 15) 60 ton FYM/ha + 150 kg urea/ha. The size of each plot was 2.0 m × 1.9 m. At the end of growth period, the plants were harvested and the concentrations of Fe, Cu, Zn, Mn and Na in their seeds, leaves and stems were measured.

The results showed that the effects of treatments on the concentrations of Fe, Zn, Cu and Mn in different sections of wheat were significant. The application of 300 kg urea/ha significantly increased Fe concentration in seed and stem, Cu concentration in leaf and stem, Mn concentration in leaf and Na concentration in stem as compared with the control. There was a significant positive correlation between Zn concentration in leaf and urea fertilizer level. The use of FYM, MSWC and MSSC significantly increased the concentrations of Fe and Zn in seed, concentrations of Fe, Zn and Mn in leaf and concentrations of Fe, Zn, Cu and Mn in stem relative to the control. The concentrations of Fe, Zn, Cu and Mn in different sections of wheat in integrated treatments especially in combined application of 150 kg urea and 60 ton FYM, MSWC and MSSC per hectare were greater than other treatments while the seed Na concentration in these treatments was lower than other treatments.

In general, in order to decrease chemical fertilizers use and achieving sustainable agriculture, improvement of Fe, Zn, Cu and Mn nutrition of wheat plant, improvement of wheat seed and straw quality, combined application of 150 kg urea and 30 or 60 ton FYM or MSWC or MSSC per hectare could be recommended at similar conditions.