الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The widespread application of conventional chemical fertilizers has led to various environmental issues, including reduced food quality, soil degradation, and harm to beneficial soil organisms. Conversely, the use of Nano-fertilizers holds promise as a potential solution to address these challenges. Therefore, the present study was conducted to evaluate the effectiveness of supplementing small quantities of Nano-fertilizers in conjunction with conventional NPK fertilizers to reduce the overall volume of traditional fertilizers when cultivating spinach plants. Moreover, the performance of micro Nano fertilizers (Fe, Zn) with spinach plants was assessed in comparison to the performance of chelated fertilizers. A split-plot experimental design was utilized, consisting of twenty treatments with three replicates, which were the simple possible combination between four NPK additions as main plots and five foliar applications of Fe and Zn as sub main factor. Main factor T1: 100% recommended dose of NPK as traditional bulk form T2: 75% recommended dose of NPK as traditional bulk form + 15% recommended dose of NPK as Nano form T3: 50% recommended dose of NPK as traditional bulk form + 15% recommended dose of NPK as Nano form T4: 25% recommended dose of NPK as Nano form Sub main factor F1: Control (without foliar) F2: Fe- Nano (10mg L-1, Fe2O3 Nanoparticles) F3: Zn- Nano (10mg L-1, ZnO Nanoparticles) F4: Fe- EDTA (100mg L-1 using Fe -EDTA 6% Fe) F5: Zn- EDTA (100mg L-1 using Zn -EDTA 6%Zn) The results obtained could be summarized as follows:- 1. Growth criteria and yield Individual effect of NPK forms The T2 treatment (75% recommended dose of NPK as traditional bulk form +15% recommended dose of NPK as Nano form) emerged as the most effective in achieving the highest values for all the all the measured growth parameters, including plant height (cm), fresh and dry weights (g plant-1), leaf area (cm2 plant-1) and yield (ton ha-1) of spinach plants at the harvest stage. It was followed closely by the T3 treatment (50% recommended dose of NPK as traditional bulk form +15% recommended dose of NPK as Nano form). In contrast, the T1 treatment (100% recommended of NPK as traditional bulk form) ranked third after both T3 and T2. Lastly, the T4 treatment (25% recommended of NPK as Nano form) was found to have the least impact on these growth parameters and yield. Individual effect of Fe and Zn forms Except fresh weights (g plant-1) which were non-significantly affected due to the studied foliar treatments, the different forms of Fe and Zn (Nano and chelated) led to a significant improvement in all the measured parameters, including plant height (cm), dry weights (g plant-1), leaf area (cm2 plant-1) and yield (ton ha-1) of spinach plants at the harvest stage, as compared to the control group (F1) that did not receive any foliar application. This underscores the positive impact of using these Fe and Zn forms on spinach plant growth and productivity. Fe treatments exhibited greater effectiveness when compared to the Zn treatments. Furthermore, the data demonstrate that the Nano form exhibited greater effectiveness when compared to the chelated form in the context of both Fe and Zn treatments. Generally, it can be noticed that the F2 treatment (Fe- Nano at rate of 10mg L-1) was the superior for obtaining the maximum values for all aforementioned traits followed by F3 treatment ( Zn- Nano at rate of 10mg L-1) then F4 treatment ( Fe- EDTA at rate of 100mg L-1) and F5 treatment (Zn- EDTA at rate of 100mg L-1), respectively. While F1 treatment (without foliar application) came in the last order. Interaction among the studied treatments Regarding the interaction effect, the combined treatment of T2 treatment (75% recommended dose of NPK as traditional bulk form +15% recommended dose of NPK as Nano form) x F2 treatment (Fe- Nano at rate of 10mg L-1) realized the highest values of plant height (cm), fresh and dry weights (g plant-1), leaf area (cm2 plant-1) and yield (ton ha-1) of spinach plants at the harvest stage, while the lowest values were noticed when spinach plants treated with 25% recommended of NPK as Nano form (T4 treatment) and simultaneously without foliar application (F1 treatment). 2. Chemical constituents 2.1. Photosynthetic pigments Individual effect of NPK forms The T2 treatment, which comprised 75% of the recommended NPK dose in traditional bulk form and 15% in Nano form, demonstrated the most effective outcome, resulting in the highest pigment values [chlorophyll a and b as well as carotene (mg g-1) at the harvest stage]. Following closely was the T3 treatment, which consisted of 50% of the recommended NPK dose in traditional bulk form and 15% in Nano form. In contrast, the T1 treatment, involving 100% of the recommended NPK in traditional bulk form, ranked third, trailing behind both T3 and T2. Lastly, the T4 treatment, with only 25% of the recommended NPK in Nano form, exhibited the least impact on the levels of photosynthetic pigments in spinach plants. Individual effect of Fe and Zn forms In both the Fe and Zn treatments, the Nano form outperformed the chelated form in terms of effectiveness, underscoring the superior impact of Nano-based nutrient delivery in promoting photosynthetic pigment levels in spinach plants. Generally, a clear pattern emerges where the F2 treatment, involving Fe in Nano form at a rate of 10mg L-1, demonstrated superior performance by recording the highest values for all the mentioned traits. Following closely was the F3 treatment, which utilized Zn in Nano form at a rate of 10mg L-1. The F4 treatment, featuring Fe in the EDTA chelated form at a rate of 100mg L-1, ranked third, while the F5 treatment, using Zn in the EDTA chelated form at the same rate, came in fourth place. Notably, the F1 treatment, which did not receive any foliar application, realized the lowest values for the assessed traits. Interaction among the studied treatments Concerning the interaction effect, the combined application of the T2 treatment (comprising 75% of the recommended NPK dose in traditional bulk form and 15% in Nano form) with the F2 treatment (involving Fe in Nano form at a rate of 10mg L-1) resulted in the highest recorded values for chlorophyll a and b, as well as carotene (mg g-1) in spinach plants at the time of harvest. In contrast, the lowest values were observed when spinach plants were subjected to the T4 treatment, which provided 25% of the recommended NPK dose in Nano form, while simultaneously not receiving any foliar application (F1 treatment). 2.2. Nutritional element concentration and uptake Individual effect of NPK forms The NPK treatments significantly affected the values of nutrient concentrations in leaves of spinach plants i.e., N, P, K (%), Fe, Zn (mg kg-1) and nutrient uptake i.e., N, P, K (g plant-1), Fe, Zn (mg plant-1) at the harvest stage. In can be noticed that the sequence order from the most effective treatment to less was as follows; T2 treatment, comprising 75% of the recommended NPK dose in traditional bulk form and 15% in Nano form followed by the T3 treatment, which involved 50% of the recommended NPK dose in traditional bulk form and 15% in Nano form then T1 treatment, utilizing 100% of the recommended NPK in traditional bulk form and lately the T4 treatment, incorporating only 25% of the recommended NPK in Nano form. Individual effect of Fe and Zn forms In both the Fe and Zn treatments, the Nano form surpassed the chelated form in terms of effectiveness, emphasizing the superior impact of Nano-based nutrient delivery in enhancing nutrient uptake levels in spinach plants. Generally, it can be noticed that the superior treatment for obtaining the maximum values of the studied nutrient concentrations and their uptake was F2 treatment, involving Fe in Nano form at a rate of 10mg L-1, followed by the F3 treatment, which utilized Zn in Nano form at a rate of 10mg L-1, then the F4 treatment, featuring Fe in the EDTA chelated form at a rate of 100mg L-1,then the F5 treatment, using Zn in the EDTA chelated form at the same rate and lately the F1 treatment, which did not receive any foliar application. Interaction among the studied treatments In terms of the interaction effect, the combined application of the T2 treatment (consisting of 75% of the recommended NPK dose in traditional bulk form and 15% in Nano form) with the F2 treatment (involving Fe in Nano form at a rate of 10mg L-1) resulted in the highest recorded values for nutrient concentrations in leaves of spinach plants i.e., N, P, K (%), Fe, Zn (mg kg-1) ,and nutrient uptake i.e., N, P, K (g plant-1) , Fe, Zn (mg plant-1) at the harvest stage. In contrast, the lowest values were observed when spinach plants were subjected to the T4 treatment, which provided only 25% of the recommended NPK dose in Nano form, while simultaneously not receiving any foliar application (F1 treatment). 3. Quality parameters Individual effect of NPK forms In terms of vitamin C (mg 100g-1), the T2 treatment, which comprised 75% of the recommended NPK dose in traditional bulk form and 15% in Nano form, demonstrated the most effective outcome, resulting in the highest values. Following closely was the T3 treatment, which consisted of 50% of the recommended NPK dose in traditional bulk form and 15% in Nano form. In contrast, the T1 treatment, involving 100% of the recommended NPK in traditional bulk form, ranked third, trailing behind both T3 and T2. Lastly, the T4 treatment, with only 25% of the recommended NPK in Nano form, exhibited the least impact on the levels of vitamin C in spinach plants. In terms of nitrate (NO3-N, mg kg-1) and oxalate (mg 100g-1), it can be noticed that their values increased as the NPK ratio in traditional bulk form increased. The highest nitrate and oxalate values were associated with the T1 treatment, which contained 100% traditional bulk NPK. The nitrate (NO3-N) concentration in the spinach varied from 251.57 to 465.50 mg kg-1 of fresh weight. These levels were below the acceptable NO3-N content for human consumption, which typically ranges from 3500 to 4500 mg kg-1 of fresh weight. This outcome suggests that traditional bulk NPK may contribute to higher nitrate and oxalate accumulation in the plant tissues, possibly due to the more abundant presence of these nutrients in the form that is easily taken up by plants. Individual effect of Fe and Zn forms The different forms of Fe and Zn (Nano and chelated) led to a significant increase in all the measured parameters, including vitamin C (mg 100g-1), nitrate (NO3-N, mg kg-1) and oxalate (mg 100g-1) at harvest stage, as compared to the control group (F1) that did not receive any foliar application. Also, the data demonstrate that the Nano form led to the highest values for vitamin C (mg 100g-1), nitrate (NO3-N, mg kg-1) and oxalate (mg 100g-1) when compared to the chelated form in the context of both Fe and Zn treatments. Generally, it can be noticed that the F2 treatment (Fe- Nano at rate of 10mg L-1) was the superior for obtaining the maximum values for all aforementioned traits followed by F3 treatment ( Zn- Nano at rate of 10mg L-1) then F4 treatment (Fe- EDTA at rate of 100mg L-1) and F5 treatment (Zn- EDTA at rate of 100mg L-1), respectively. While F1 treatment (without foliar application) came in the last order. Interaction among the studied treatments In terms of vitamin C (mg 100g-1), the combined treatment of T2 treatment (75% recommended dose of NPK as traditional bulk form +15% recommended dose of NPK as Nano form) x F2 treatment (Fe- Nano at rate of 10mg L-1) realized the highest values. In terms of nitrate (NO3-N, mg kg-1) and oxalate (mg 100g-1), it can be noticed from the same Table that the combined treatment of T1 treatment (100% recommended dose of NPK as traditional bulk form) x F2 treatment (Fe- Nano at rate of 10mg L-1) realized the highest values. CONCLUSION The study highlights the effectiveness of supplementing traditional NPK fertilizers with Nano-fertilizers, particularly when combined with foliar applications of Fe and Zn, in enhancing the growth, chemical constituents, and quality parameters of spinach plants. The combination of 75% recommended NPK in traditional bulk form and 15% in Nano form, along with Fe- Nano foliar treatment at a rate of 10mg L-1, consistently resulted in the highest positive impacts across various parameters. These findings suggest the potential for more sustainable and efficient fertilizer practices in spinach cultivation. Therefore, it is recommended that farmers and agricultural practitioners consider adopting this approach to optimize crop performance while minimizing the environmental impact of conventional chemical fertilizers.