Long-term use of chemical fertilizers is affecting the environment, soil quality, and biodiversity. Organic agriculture is gaining global attention by using microbial-based biofertilizers. Carriers protect microbes by providing nutrition, energy, and suitable conditions for their survival while entering the natural environments. The purpose of this study was to evaluate the ability of different carrier materials to enhance the yield and the quality of spinach and to select the best carrier material for spinach biofertilizer. Three pre-isolated and characterized bacterial strains (AN-35, ZM-27, and ZM-63) were tested for their compatibility and used in this experiment through seed inoculation with organic carriers, i.e., compost, peat, press mud, biochar, and charcoal. A pot experiment and a field experiment were conducted to evaluate the efficacy of different organic carriers. The results of the pot study showed a significant increase in spinach growth, i.e., shoot length (25%), shoot fresh weight (24%), root length (25%), and root fresh weight (29%), spinach nutrition, i.e., nitrogen (18%), phosphorus (22%), potassium (15%), iron (17%), and zinc (14%), spinach physiology, i.e., relative water content (27%), chlorophyll content (9%), and the membrane stability index (28%) under peat coated treatments with 24% more soil microbial populations compared to the control. Similarly, in the field experiment, peat coating significantly enhanced spinach growth, i.e., shoot length (29%), shoot fresh weight (23%), root length (16%), and root fresh weight (24.7%), spinach nutrition, i.e., nitrogen (16%), phosphorus (19%), potassium (15%), iron (17%), and zinc (23%), spinach physiology, i.e., relative water content (28%), chlorophyll content (13%) and the membrane stability index (32%), and spinach yield per hectare (30%), as well as producing 20% higher soil microbial populations. From these results, it is concluded that peat is a good carrier material for biofertilizer production as it not only enhances crop production but also the microbial number, in addition to improving soil quality.

Zinc (Zn) is critical for the activity of many enzymes including involved photosynthetic CO₂ fixation and indirectly involved in the production of growth hormones and internode elongation in crop plants. In this regard, a field experiment was conducted to investigate the comparative effectiveness of the Zn blended, Zn coated and bio-activated Zn coated urea on the growth, physiological, yield, and quality of wheat. Three types of urea were prepared including bio-activated Zn coated, Zn coated and Zn blended urea. The bio-activated Zn coated urea was prepared by inoculating the powdered organic material with Zn solubilizing bacterium (Bacillus sp. AZ6) and then this material was mixed with ZnO. This bioactive Zn was coated on urea at the rate to formulate 1.5% bio-activated Zn coated urea. Moreover, Zn blended urea was prepared by mixing powder ZnO with urea while Zn coated urea with 1.5% Zn was prepared by mixing ZnO and urea under proper moisture conditions to ensure proper coating. In results, growth parameters were significantly increased with the application of bio-activated Zn coated urea as compared to other urea formulations and the control. The same treatment caused the maximum increase in quality parameters like oil contents (55%), protein (30%), and N concentration (30%) as compared to the control. In conclusion, the application of 1.5% bio-activated Zn coated urea was highly effective in enhancing the growth, physiological, yield, and quality parameters of wheat.

Zinc (Zn) biofortification in staple cereal grains is a low-cost and viable option to overcome the Zn deficiency in humans beings in developing countries. Intensive cropping with no/low micronutrient fertilization has resulted in soil Zn deficiency around the globe. Moreover, the Zn use efficiency of soils is usually low owing to its fixation into unavailable forms. Hence, the present study was conducted to investigate the integrated effects of urea coated with bioaugmented Zn on wheat growth, yield, and Zn biofortification. The bioaugmented Zn was prepared by inoculating ZnO with Bacillus sp. AZ6. Three levels (0.5, 1.0, and 1.5%) of ZnO, bioaugmented Zn, and bioaugmented Zn+organic material were coated on urea fertilizer and applied to investigate the performance of the wheat crop. The applied treatments were compared with absolute control and sole application of ZnSO4, and Bacillus sp. AZ6. Results revealed that the application of urea coated with 1.5% bioaugmented Zn significantly increased wheat growth, yield, and Zn biofortification as compared to the sole ZnSO4, and Bacillus sp. AZ6 treatments. The application of urea coated with 1.5% bioaugmented Zn improved the accumulation of Zn in shoots and grains by 83.3% and 144.0%, respectively, compared to absolute control. The increase in grain Zn content was owing to the significant reduction in grain phytic acid (69.9%) and phytate:Zn molar ratios (87.6%) compared to absolute control. Therefore, it was concluded that the application of urea coated with bioactivated ZnO can improve Zn biofortification in wheat grain by reducing phytic acid concentrations, consequently fulfilling human Zn needs through the consumption of such Zn enrich wheat grains.

The major cause of reduced Zn availability to plants in Pakistan is unfavorable soil factors (alkaline pH and calcareousness). Different strategies can be adopted, to enhance the Zn bioavailability in the rhizosphere and cereals. Among all strategies, a novel technique is the coating of Zn on macronutrient fertilizers like urea. By adopting this technique, dual benefits can be achieved for example Zn and N become available to plants and on the other hand, the loss of urea can be minimized. Firstly, Engro Zabardast Urea was taken from Engro Fertilizers Pvt. Ltd and evaluated for coating effect on urease activity and Zinc release pattern with time (up to 70 days). Then 100%, 90%, 85%, and 80% recommended EZU (Engro Zabardast Urea) were tested to find out the increase in urea efficiency by coating. From the results of the release experiment, it was concluded that EZU @ 90% of the recommended dose showed maximum results of Zn release respective to time and vice versa for urease activity. Secondly, a pot experiment was conducted to evaluate the above-mentioned prepared products on agronomic parameters and Zn and nitrogen concentration in 45 days of maize seedlings. Zn concentration in maize seedlings increased with the application of 90 and 85% of the recommended EZU, respectively. Similar results were found under field conditions with the application of 90% of recommended EZU growth, physiological parameters, and grains and stover yield were improved and Zn contents in grains were enhanced. From the results of all experiments, it can be concluded that EZU is a fantastic product not only to increase Zn bioavailability/fortification but also to reduce nitrogen losses. This product has the potential to reduce the use of plain urea by up to 10%. This ecofriendly approach cannot only reduce extra labor costs but also the ignorance of Zn application by the farming community can also be addressed.