Green Synthesis of Nanofertilizers and Their Application as a Foliar for Cucurbita pepo L: The implementation of nanofertilizers in agriculture is the purpose in specific to decrease mineral losses in fertilizing and raises the yield during mineral management as well as supporting agriculture development. Hence, this experiment was conducted in Shebin El-Kom, El-Monifia governorate, Egypt, during two seasons 2017 and 2018 to study the effect of micronutrient oxide nanoparticles of zinc, iron, and manganese, as well as combination between these oxides as a foliar application on the growth, yield, and quality of squash plants. The obtained results showed that the spraying of manganese oxide nanoparticles on the plants led to the best vegetative growth characteristics, also, the characteristics of the fruits, yield, and the content of photosynthetic pigments. On the contrary, the content of organic matter, protein, lipids, and energy gave the highest value in squash fruits that have been sprayed with iron oxide nanoparticles.

Manganese, zinc, and iron are the most essential micronutrients required for plant growth and applied as foliar fertilizers. Herein, a simple template-free microwave-assisted hydrothermal green synthesis technique was adapted to produce manganese zinc ferrite nanoparticles (Mn0.5Zn0.5Fe2O4 NPs) at different temperatures (100, 120, 140, 160 and 180 °C). The prepared nanomaterials were employed at different concentrations (0, 10, 20, and 30 ppm) as foliar nanofertilizers during the squash (Cucurbita pepo L) planting process. X-ray diffraction patterns of the prepared nanomaterials confirmed successful production of the nanoferrite material. The prepared nanofertilizers showed type IV adsorption isotherm characteristic for mesoporous materials. FE-SEM and HR-TEM imaging showed that the nanoparticles were cubic shaped and increased in particle size with the increase in microwave temperature during production. The impact of application of the synthesized ferrite nanoparticles on vegetative growth, proximate analysis, minerals content and the yield of squash plant was investigated for two consecutive successful planting seasons. The nanoferrite synthesized at 160 °C and applied to the growing plants at a concentration of 10 ppm gave the highest increase in % yield (49.3 and 52.9%) compared to the untreated squash for the two consecutive seasons, whereas the maximum organic matter content (73.0 and 72.5%) and total energy (260 and 258.3 kcal/g) in squash leaves were obtained in plants treated with 30 ppm ferrite nanoparticles synthesized at 180 °C. On the other hand, the maximum organic matter content (76.6 and 76.3%) and total energy (253.6 and 250.3 kcal/g) in squash fruits were attained with plants supplied by 20 ppm ferrite nanoparticles synthesized at 160 °C. These results indicate that the simple template-free microwave-assisted hydrothermal green synthesis technique for the production of manganese zinc ferrite nanoparticles yields nanoparticles appropriate for use as fertilizer for Cucurbita pepo L.