Nanoparticles (NPs), due to their suitable properties, serve as a potential source of nutrients for the biomicrochemistry of edible grains. Chickpeas are a valuable legume, widely consumed in developing countries. Therefore, to improve the Zn and Fe content in chickpeas, a two-year study was performed to test the potential of foliar application (0.5% Zn and Fe), chelated (0.3 % Zn and Fe) and nanoform (0.5% ZFN) of fertilizers to enhance Zn and Fe content in chickpeas. Foliar application of 0.5% nano zinc oxide ZnO NP + 0.5% nano iron oxide Fe2O3 NPs (ZFN) at the pre-flowering stage showed the highest potential to increase seed yield, Zn and Fe content and Their absorption when foliar application once with nano fertilizer gave results comparable to two times of mineral and chelated foliar application. Cereal and straw yields (14.07 and 33.04 q ha −1 , respectively) were significantly higher in the ZFN treatment than in the control (9.20 and 27.49 q ha −1 respectively) ). A similar trend was observed for the Zn and Fe content of cereals (42.29 and 86.51 mg kg −1 , respectively). As for nutrient uptake, ZFN treatment showed the highest Zn and Fe absorption in cereals (604.49 and 1226.22 g ha −1 , respectively) and straw (729.55 and 9184, respectively). 67 g ha −1, respectively). Therefore, nanofertilizers, due to their altered structural properties, exhibit higher conversion than mineral and chelating nutrient forms, thereby improving yield and nutrient content. at a higher level. Therefore, foliar application of 0.5% nano zinc oxide ZnO NPs + 0.5% Fe2O3 NPs could prove to be a viable option to enrich chickpeas with Zn and Fe to improve malnutrition. in developing human populations.
Chickpeas ( Cicer arietinum L.) are considered an important legume that is widely used as food and forage globally. It serves as the main source of dietary protein for the majority of people in developing countries among all the surrounding crops. In addition to protein, chickpeas contain a significant amount of carbohydrates [ 1 ]. Chickpeas have always maintained an important position, ranking second in area (15.3% of the total) and third in production (15.4%) globally [ 2 ]. Global chickpea consumption has increased by 14.2% in area and 27.3% in production since 2010 [ 2]. Growing chickpeas offers various advantages such as adaptability to a wide range of climates, low farming costs and enhanced nitrogen fixation, thus improving soil fertility [ 3 ]. Micronutrient deficiencies of zinc (Zn) and iron (Fe) are currently a major problem in developing countries due to the use of high yielding varieties, intensive farming systems, and inadequate supply of micronutrients. nutrients and loss of organic matter due to erosion and pollution. Micronutrients are needed in small amounts for plant growth and development and their deficiency can lead to disruptions in physiological and metabolic pathways in plants [ 4]. Using trace elements in fertilizers mixed with conventional chemical fertilizers may not be helpful for plant growth and yield increase [ 4 , 5 ].
Zinc deficiency is most common in developing countries, where the majority of the population consumes cereals as a staple food [ 6 , 7 ]. There is sufficient evidence of Zn deficiency in chickpea growing regions of the world. The main soil factors affecting Zn availability are low total Zn content, high pH, high calcite, and low organic matter content. Zinc acts as an essential structural entity of many enzymes involved in auxin and carbohydrate metabolism, in protein synthesis, and in the structural integrity of cell walls [ 8 , 9 ]. Furthermore, it has important roles in pollen development, fertilization and chlorophyll synthesis [ 7 , 10]. Zinc fertilization improves water efficiency [ 11 ], root structure and nitrogen fixation. Therefore, Zn is an essential element to improve the overall plant growth and nutritional status [ 12 ]. Iron (Fe) is also known as an essential micronutrient for plants because it participates in a number of metabolic processes such as photosynthesis and respiration [ 13 , 14]. Although Fe exists in abundance in the earth’s crust, lower solubility in soil will reduce Fe uptake by plants and lead to Fe deficiency in human populations. Although the Fe requirement of plants is small, it plays an important role in plant growth and yield. Insufficient Fe supply leads to impaired plant growth and crop quality parameters and should be corrected through appropriate approaches [ 15 , 16 ]. Normally, the amount of Zn and Fe in the soil exceeds the needs of the plant, but the plant cannot absorb it easily because they are unavailable or leached. The best alternative is to apply these micronutrients as a foliar spray.
The term ‘biofertilizer’ refers to the enrichment of nutrients in the edible parts of plants through the exogenous supply of nutrients in the form of fertilizers or through conventional propagation methods. often to develop micronutrient-fortified crop varieties. Progress in conventional farming methods has been slow and uncertain. Thus, agronomic methods provide economical and efficient ways to overcome nutrient deficiencies in humans.
Recent studies have shown the effectiveness and sustainability of fertilization methods to improve micronutrient concentrations in plants [ 17]. To date, many Zn fertilizers have been used to ameliorate Zn deficiency in plants, such as inorganic Zn compounds, including carbonates, oxides, chlorides, nitrates or sulfates. The use of synthetic chelates such as ethylenediamine tetra-acetic acid (EDTA) has also been made to enrich Zn in plants [ 18 ]. The response of a particular crop varies with variations in Zn sources due to differences in uptake and transport efficiencies within the plant [ 19 ], and with variation in fertilization methods. , such as soil, leaf or seed treatment [ 20]. Since the 1950s, the effectiveness of synthetic chelates to enhance the bioavailability and absorption of micronutrients by plants grown in limestone soils has been studied in a variety of crops under different conditions. different environmental conditions [ 21 ]. Synthetic Fe chelates such as Fe-EDTA and Fe-EDDHA are also known to mitigate Fe deficiency and improve Fe status in plants [ 22 ]. Fe chelate has been used through soil, foliar or seed treatment to increase Fe availability, crop yield and plant nutritional quality [ 23 ]. Among these, foliar applications are well known to enhance the nutrient content of plants. Foliar application of Zn through Zn-EDTA increased the nutritional status of rice grains [ 24]. In wheat, the effect of leaf application of Zn-EDTA was greater than that of ZnSO 4 in increasing Zn [ 25 ] content. Another report states that in triticale, application of Zn-EDTA has been shown to be effective in increasing agricultural yields under stress drought conditions [ 26 ]. In chickpeas, Zn-EDTA has been shown to increase cereal Zn concentrations [ 27 ].
The use of nanomaterials as fertilizer has emerged as a suitable alternative to conventional fertilizers due to its unique structural characteristics and high efficiency. The size of nanomaterials ranges from 1 to 100 nm. In the last few years, nano-fertilizers have attracted strong interest in agricultural management [ 28 ]. New generation fertilizers based on nanotechnology have been proposed as a viable alternative to avoid the fundamental agricultural problems associated with the application of conventional fertilizers [ 29 ]. Nanoparticles have a high surface-to-volume ratio, thus providing more active absorption/adsorption sites than bulk materials [ 30 , 31]. The main problem associated with chickpeas is a lack of micronutrients, which leads to malnutrition in humans as well as animals. Therefore, it is necessary to prepare fertilizers rich in micronutrients to reduce nutrient deficiencies in the soil, improve crop yields, and minimize micronutrient malnutrition in humans and animals. object. Therefore, this study aimed to investigate the effect of mineral foliar application, EDTA and nanoforms of zinc oxide and nano iron oxide on grain yield, as well as nutritional components in chickpeas, to determine Best treatment method to enhance Zn and Fe content in this crop.
Materials and methods
The experiment was started in Rabi in 2019 and 2020 (November to April) at the Research Farm Area, Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab, on the Indo-Gangetic plane in the northwest. India (30° 56 ′ N, 75° 52 ′ E and 247 m above mean sea level) at the same GPS location as mentioned above. Rainfall in the October-April crop was 219 mm and 68.9 mm, respectively, during 2019–20 and 2020–21. The average monthly maximum temperature of the study area varies from 15.9°C to 32.8°C during 2019–20 and 16.4°C to 34.2°C during 2020– 21, however, minimum temperatures vary from 6.7°C to 18.4°C during 2019–20 and 7.1°C to 17.0°C during the 2020–21 growing season ( Fig. first). These data were obtained from the Department of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana. In this study, the experiment consisted of 16 treatments with three replicates in a completely randomized block design.
Figure 1. Average monthly minimum and maximum temperature, relative humidity and precipitation of the experimental area.
The soil of the experimental area is sandy loam, pH 7.23, EC = 0.33 dS m −1 , and soil organic carbon content is 0.34%. Initial micronutrient levels, viz. Zn, Cu, Fe and Mn, in soil are 1.19, 0.62, 5.12, and 3.90 mg kg −1 [ 32]. The chickpea variety used for the experiment was PBG 7. This variety was recommended by Pulse Division, Department of Genetics and Plant Breeds, Punjab Agricultural University, Ludhiana. Inoculation of chickpea seeds involves moistening the seeds with a minimum amount of water. Mesorhizobium (LCR-33) and Rhizobacterium (RB-1) biofertilizers were each mixed with the above seeds. These bio-fertilizers are available at Punjab Agricultural University, Ludhiana seed shop at Gate 1 and Krishi Vigyan Kendra / Farm Advisory Service Center, located in different districts of the state. The inoculated seeds were dried in the shade and sown within one hour of inoculation. Seeding was carried out during the first week of November by drilling method and row spacing was kept at 30 cm and plot size was 14.4 m2 (4.8 m×3.0 m). Foliar applications of different Zn and Fe sources have been used, i.e. mineral, chelating and nanoforming, to compare their potential as trace fertilizers. Analytical grade chemicals of Zn and Fe, i.e. ZnSO 4 .7H 2 O (0.5%) and FeSO 4 .7H 2 O (0.5%), were used, respectively. Chelated forms of Zn and Fe in the form of EDTA-Zn (0.3%) and EDTA-Fe (0.3%) were used as foliar sprays, respectively. However, for nano-zinc oxide ZnO-NPs (0.5%) and nano-Fe2O3 (0.5%), their suspensions were prepared by sonication for two hours, to obtain a copper mixture. especially in the case of nano-fertilizers. The treatment details are given in Table 1. For the analysis of Zn and Fe, the DTPA method was used [ 33 ] and the concentrations of Zn and Fe were determined using an atomic absorption spectrometer (Varian Model). AAS-FS 240).
Table 1. Treatment details of field experiments.
Synthesis of nanoparticles
Suitable levels of 0.5% nano zinc oxide ZnO NP and 0.5% Fe2O3 NP (ZFN) were synthesized by sol-gel method [ 34 ] for application on different growth stages of legumes chicken. Briefly, metal nitrate (M = Zn, Fe) and citric acid were dissolved in deionized water. The reaction mixture was stirred at 70 °C to 80 °C and the pH was adjusted to 8.0 with NH 4 OH solution. After 2 h, the sol was converted to a gel, which was dried at 100 °C in an oven for 8 h. The dried gel was calcined for 3 h in a furnace at 300 °C to obtain the final product, metal oxide.
Plant analysis to estimate DTPA-Zn and Fe
Cereal and straw samples were collected after harvest in the second week of April. Samples were air-dried, then oven-dried at 60 °C. Grain and straw yields were recorded from the real plot, ignoring boundary rows, and then converted to q ha −1 . A representative grinded straw sample (1.0 g) and grain sample (0.5 g) were taken for digestion and digested in a diacid mixture containing HNO3 and HClO 4 (3:1) acids on electric stove [ 35]. The concentrations of micronutrients (Zn and Fe) in the digested plant extracts were determined using an atomic absorption spectrometer (Varian Model AAS FS 240). Micronutrient absorption in cereals and rice straw was calculated by multiplying the concentration by the respective yield [ 36 ].
Fertilizer costs (USD ha -1 ) for different treatments in the experiment were calculated separately according to the prevailing price of fertilizer in USD at the time of use [ 37 ]. The total return (value of additional production) was calculated by the Indian government based on the MSP (minimum support price) of chickpeas during the years studied. Net profit/ha (USD ) is calculated by subtracting fertilizer cost from total profit, as shown below.
Data were analyzed using statistical analysis software (SPSS software, 19.0; SPSS Institution Ltd., Chicago, IL, USA). One-way analysis of variance (ANOVA), followed by Duncan’s multiple range test, was performed to determine treatment effects at the 0.05 probability level.
Effect of foliar application of Zn and Fe on grain and straw yield of chickpeas
In both study years, foliar application of Zn and Fe at the pre-flowering + fruiting stage showed a significant impact on the seed and straw yield of chickpeas, regardless of the source used ( Table 2 ). . However, there was no significant effect of foliar application on straw yield in the second year.
Table 2. Effect of mineral, chelated and nanoform (nanozinc oxide) of Zn and Fe on grain and straw yield of chickpeas.
In contrast, applying nutrients only at the pre-flowering stage did not significantly increase seed yield. The highest grain yield in two years was recorded in treatment T13 (14.10 q ha -1 ) compared with control treatment T1 (9.20 q ha -1 ), in which foliar application of 0.3% Zn -EDTA + 0.3% Fe-EDTA was performed, together with RDF applied at the pre-flowering + fruiting stage. The results of treatment T13 were equal to those of treatment T7 (RDF + 0.5% (12.50 q ha -1 for one spray) ZnSO 4 .7H 2 O + 0.5% FeSO 4 .7H 2 O spray period pre-flowering + fruit formation) and T16 (RDF + of 0.5% nano zinc oxide ZnO NP + 0.5% Fe2O3 NP sprayed at pre-flowering stage), in which seed yield respectively are 13.90 q ha -1 and 14.07 q ha -1 . Therefore, the single application of Zn and Fe gives equivalent results compared with the two applications in their mineral and chelating forms. Furthermore, foliar spraying of only Zn and Fe minerals at the pre-flowering stage did not significantly increase the seed yield of chickpeas. However, in the second year, there was no significant impact on straw yield. Furthermore, two-year mean data indicated that foliar application of Zn and Fe did not significantly increase chickpea straw yield, regardless of origin and application time.
Impact of foliar application of Zn and Fe on cereals Zn and Fe concentrations of chickpeas
Two-year data on the response of grain Zn concentrations in chickpeas to single and combined foliar application of Zn and Fe through different sources and at different growth stages were obtained. presented in Table 3 .
Table 3. Effect of minerals, chelators and nanoforms (nano zinc oxide) of Zn and Fe on the concentration of Zn and Fe in chickpeas.
The mean values demonstrate that the use of Zn + Fe in combination or Zn alone significantly improved the Zn concentration in chickpeas compared with the control (37.52 mg kg -1 ), regardless of the source used. use. The maximum concentration of Zn was observed in treatment T13 (42.92 mg kg -1 ), in which chickpeas were treated with RDF + 0.5% nano zinc oxide ZnO NP + 0.5% Fe 2 O 3 NP in the pre-flowering stage. Therefore, a single application of the NP suspension increased the amount of Zn in chickpeas more than two sprays of the chelated form of the fertilizer. These results are statistically equal to those obtained in treatments T10 (41.68 mg kg −1 ), T11 (41.99 mg kg −1 ), T13 (42.92 mg kg−1), T13 (42.92 mg kg−1), T13 (42.92 mg kg−1). 1 ) and T15 (42.26 mg kg −1 ).
Two-year data on Fe concentrations in chickpeas affected by single and combined leaf applications of Zn and Fe through different sources and at different growth stages are presented. in Table 3 . The mean values showed that Fe alone or combined Zn + Fe applications significantly improved Fe concentrations in chickpeas compared with controls (66.74 mg kg -1 ), regardless of the source used. use. The maximum Fe concentration was recorded in treatment T16 (86.51 mg kg -1 ), in which chickpeas were treated with RDF + 0.5% ZnO NP + 0.5% Fe 2 O 3 NP at stage before flowering. The results were statistically equal with treatments T3 (86.13 mg kg -1 ), T6 (85.31 mg kg−1 ) and T7 (84.33 mg kg −1 ). Therefore, a combined spray of nanoparticle suspension will increase the amount of Fe in chickpeas more than two sprays of Fe alone or combined Zn + Fe mineral fertilizers.
Effect of foliar application of Zn and Fe on the concentration of Zn and Fe in the straw of chickpeas
Two-year data on Zn concentrations in rice straw in chickpeas related to separate and combined foliar applications of Zn and Fe through three different sources and at different growth stages were obtained. presented in Table 4 .
Table 4. Effect of minerals, chelators and nanoforms (nano zinc oxide) of Zn and Fe on the concentration of Zn and Fe in chickpea straw.
The mean data indicated that the combined application of both Zn and Zn + Fe significantly improved the Zn straw concentration in chickpeas compared with the control (14.11 mg kg -1 ), regardless of the source used. The maximum Zn concentration in rice straw was observed in treatment T16 (20.70 mg kg -1 ), in which chickpeas were treated with RDF + 0.5% nano zinc oxide ZnO NP + 0.5% Fe2O3 NP at the pre-flowering stage. The results are statistically equivalent to the treatments T2 (19.73 mg kg −1 ), T5 (18.68 mg kg −1 ), T7 (19.34 mg kg −1 ), T8 (19.69). mg kg −1 ), T10 (20.63 mg kg -1 ), T11 (19.26 mg kg −1 ), T13 (18.79 mg kg−1 ) and T15 (20.66 mg kg −1 ).
The effects of isolated and combined applications of Zn and Fe on chickpea leaves through different sources on the Fe concentration in rice straw are presented in Table 4 . Data recorded over two years showed that Fe alone or combined Zn + Fe applications significantly improved the Fe concentration in the straw compared with the control (176.89 mg kg -1) regardless of the source. use. Among the different source forms, the single use of the Fe2O3 NP suspension recorded the highest Fe concentration, as the highest results were obtained in treatment T14 (269.52 mg kg -1 ). Thus, Fe2O3 NPs applied at the pre-flowering stage were found to be more effective in increasing the Fe concentration in straw than single or double application of mineral or chelating sources.
Effect of foliar application of Zn and Fe on cereals Zn and Fe absorption of chickpeas
The Zn absorption of chickpeas was significantly increased by single and combined application of Zn and Fe through mineral, chelate and NP sources and at different growth stages. These results, together with the vertical error bars describing the standard deviations for the triplets, are presented in Figure 2
Figure 2. Effect of minerals, chelates and nanoforms of ( A ) Zn and ( B ) Fe on the absorption of Zn and Fe in chickpeas. Within each bar, means with similar or dissimilar letter(s) were evaluated with the least significant multiple band difference (LSD) test, using the probability level p ≤ 0.05.
Maximum Zn absorption was observed in treatment T16 (604.49 g ha -1 ), in which chickpeas were treated with NP RDF + 0.5% ZnO + 0.5% Fe2O3 NP in the previous stage. when flowering. The results were statistically equivalent to treatments T7 (563.06 g ha −1 ) and T13 (595.10 g ha −1 ). The least Zn absorption in chickpeas was observed in treatment T1 (345.51 g ha -1 ), which was used as a control. Valuable two-year data on Fe uptake by chickpeas as affected by single and combined foliar application of Zn and Fe through different sources and at different growth stages are shown. in Figure 2. Average values showed that the application of Fe alone or Zn + Fe in combination significantly improved the Fe uptake of the grains compared with the control (613.91 g ha -1 ) , regardless of the source used. Maximum Fe absorption was observed in treatment T16 (1226.22 g ha -1 ), in which chickpeas were treated with RDF + 0.5% nano zinc oxide ZnO NPs + 0.5% Fe2O3 NP at pre-flowering stage. The results were statistically equivalent to the treatment T7 (1186.29 g ha −1 ), in which the fertilizers applied were RDF + 0.5% ZnSO 4 .7H 2 O + 0.5% FeSO 4 . 7H 2 O spray period before flowering + fruit formation. Thus, the combination of nano zinc oxide ZnO + Fe2O3 NP suspension made chickpeas absorb more Fe than the two single sprays of Fe or the combined Zn + Fe mineral fertilizers.
Effect of foliar application of Zn and Fe on the absorption of Zn and Fe in the straw of chickpeas
Two-year data on Zn uptake by rice straw in chickpeas as affected by separate and combined foliar application of Zn and Fe through three different sources and at different growth stages presented in Figure 3 .
Figure 3. Effect of minerals, chelates and nanoforms of ( A ) Zn and ( B ) Fe on the absorption of Zn and Fe in chickpea straw. Within each bar, means with similar or dissimilar letter(s) were evaluated with the least significant multiple band difference (LSD) test, using the probability level p ≤ 0.05.
The mean data indicated that the use of both Zn and Zn + Fe in combination significantly increased Zn absorption in straw compared with control (389.47 g ha -1 ), regardless of the source used. Straw absorbed maximum Zn in treatment T16 (729.55 g ha -1 ), in which chickpeas were treated with RDF + 0.5% nano zinc oxide ZnO NP + 0.5% Fe2O3 NP in the previous stage. when flowering. The results are statistically equivalent to treatments T5 (670.13 g ha −1 ), T10 (692.57 g ha −1 ), T11 (653.76 g ha −1 ) and T15 (651.28 g ha −1 )). The results also showed that Fe sole application recorded significantly lower Zn absorption than the treatments with Zn in the leaf mixture. Furthermore, the application of NPs at the pre-flowering stage shows more potential results than double application of mineral or chelate.
The effect of isolated and combined applications of Zn and Fe in chickpea leaves through different sources on the Fe uptake of rice straw is illustrated in Figure 3 . Data recorded over two years showed that Fe application alone or Zn + Fe combination significantly increased the Fe uptake of the straw compared with the control (4614.27 g ha -1 ) regardless of the source used. use. Among the different source forms, maximum Fe absorption was observed when 0.5% nano zinc oxide ZnO NPs + 0.5% Fe2O3 NPs were applied at the pre-flowering stage. Therefore, the highest results were obtained in treatment T16 (9184.67 g ha −1). Therefore, single application of Zn and Fe NPs is found to be more effective for increasing Fe absorption than single or double application of mineral or chelating sources. Furthermore, treatments using Zn alone showed significantly lower Fe uptake than treatments with Fe in the leaf mixture.
Economic analysis showed that the cultivation cost was highest for treatment T16 (532.8 USD ), followed by treatment T15 and T14 with farming costs of 475.7 USD and 458.3 USD , respectively. Similarly, the highest net profit was recorded for treatment T13 (886.2 USD ), followed by T7 (882.2 USD ) and T6 ( 813.7 USD). Meanwhile, the B:C ratio was highest in treatment T7 (3.11), followed by T13 (3.05), as shown in Table 5 .
Table 5. Effect of minerals, chelators and nanoforms (nano zinc oxide) of Zn and Fe on the economics of chickpeas.
Impact of Zn and Fe on grain and straw yield of chickpeas
The results of this study indicated that the cereal and straw yield of chickpeas increased significantly over two years compared with the control, regardless of the source used. These results may be related to the higher Zn availability due to the Zn supply, which promotes chlorophyll synthesis and plant photosynthetic apparatus, leading to yield and dry mass accumulation. higher. Similar results, showing increased yields using Zn and Fe, were also reported in maize and wheat, [ 38 , 39]. Cereal yields were also improved with foliar application of Fe, possibly due to improved carbohydrate and protein synthesis, as well as photosynthesis rate. In addition, Fe plays an important role in the synthesis of growth promoters such as auxins, seed maturation, nucleic acid metabolism and chlorophyll synthesis [ 13 , 14 ]. Therefore, improvements in these parameters lead to higher grain yields. Two applications of Zn and Fe increased grain yield to a greater extent than single application due to higher supply of Zn and Fe compared with single application. Furthermore, suspensions of 0.5% nano zinc oxide ZnO NPs + 0.5% Fe2O3 NPs were found to be more effective than bulk mineral and mineral forms. NPs show higher absorption and metabolism efficiency than bulk forms [40 ]. The present results are in agreement with previous studies, in which the application of ZnO in sorghum resulted in higher yields than those of large [ 40 ].
Effects of Zn and Fe on their seed and straw concentrations in chickpeas
Foliar application of Zn and Fe, individually and in combination, resulted in significantly higher concentrations of Zn and Fe in chickpea seeds and straw compared with the control. The results relate to the immediate availability of nutrients, since in foliar fertilization the nutrients are directed to the leaves. Similar results, showing an increase in Zn concentrations in wheat and rice, were reported using exogenous Zn supplies [ 41 , 42]. Two nutrient applications increase nutrient content to a greater extent than single application, which is due to higher nutrient availability when the nutrient source is applied twice. The combined application of Zn and Fe had a positive effect on the Zn and Fe content of chickpeas and rice straw; therefore, it can be inferred that Zn and Fe have a similar metabolism to cereals [43 ]. Nanoparticles give outstanding results under Zn and Fe concentrations in cereals and rice straw, as a single application of 0.5% nano zinc oxide ZnO NP + 0.5% Fe2O3 NPs has similar efficacy. equivalent to the dual application of bulk sources. These results are probably due to the higher metabolism of the nanofertilizers compared to their bulk fertilizers [44 ]. Similar results showing the higher efficiency of nanofertilizers compared with the bulk form were reported previously [ 40 ].
Effects of Zn and Fe on their absorption of cereals and straw in chickpeas and economic analysis
Foliar application of Zn and Fe fertilizers resulted in higher Zn and Fe absorption in chickpeas and rice straw. These results relate to the availability of nutrients and their metabolism in plant parts. The delivery of exogenous nutrients through different fertilizers resulted in higher nutrient availability compared with the control. Similar results, showing an increase in micronutrient absorption in oats, were reported when exogenous Zn supplies were used . Two applications of nutrients at different growth stages showed higher nutrient availability for absorption and metabolism in plant parts than single application. Nanofertilizers show more potential in increasing Zn and Fe uptake than the bulk form, as a single application of the nanofertilizer is equally effective compared with two applications using multiple sources. These results may be due to the higher metabolism of nanofertilizers compared with their bulk fertilizers [46 ]. Similar results, showing a higher efficiency in nutrient absorption of nano-fertilizers compared to the bulk form, were reported in coffee plants [ 47]. The cost of culture in treatment T16 was the highest due to the cost of ZnO NP and Fe2O3 NP zinc oxide nanoparticles used in the treatment process. However, net profit was highest in treatment T13, which is statistically equal to treatment T7. The B:C ratio showed the highest value in treatments T7 and T13 due to lower cost of mineral fertilizers and EDTA.
The results of this study suggest that zinc oxide and iron oxide nanomaterials – due to their special structural features – can be used as potential sources of nutrients instead of mineral and chelated substances of them to enrich the chickpeas with minerals. The combined application of 0.5% nano zinc oxide ZnO NPs + 0.5% Fe2O3 NPs (ZFNs) at the pre-flowering stage significantly increased yield, nutrient content and nutrient uptake. and the results are comparable to both mineral and chelated applications. The results also demonstrate a significant role of Zn and Fe in improving grain and straw yield, as foliar application of Zn and Fe increases chickpea yield due to greater availability of nutrients, regardless of source used. However, the B:C ratio was highest for treatments T7 and T13, but treatment T16 (related to NP) could be used as an alternative to other fertilizers. Therefore, the use of multi-nutrient blends of nano-fertilizers should be paid special attention to in order to improve the yield and nutritional content of chickpeas to combat micronutrient malnutrition.
by Salwinder Singh Dhaliwal 1ORCID,Vivek Sharma 1ORCID,Arvind Kumar Shukla 2ORCID,Vibha Verma 1ORCID,Sanjib Kumar Behera 2ORCID,Prabhjot Singh 1,Saqer S. Alotaibi 3ORCID,Ahmed Gaber 4,*ORCID andAkbar Hossain 5,*ORCID
1 Department of Soil Science, Punjab Agricultural University, Ludhiana 141004, India
2 Indian Institute of Soil Science, Bhopal 462038, India
3 Department of Biotechnology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
4 Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
5 Department of Agronomy, Bangladesh Wheat and Maize Research Institute, Dinajpur 5200, Bangladesh
* Authors to whom correspondence should be addressed.