Viruses pose a serious threat to the sustainable production of economically important crops around the world. In the past 20 years, potato virus Y (PVY) emerged as a relatively new and very serious problem in potatoes, even though it is the oldest known plant virus. Multiple strains of the virus cause various symptoms on the leaves and tubers of potatoes, resulting in yield reduction and poor-quality tubers. Consequently, it would be very interesting to learn what causes systemic PVY resistance in plants. Natural compounds such as chitosan (CHT) and phosphorus have been developed as alternatives to chemical pesticides to manage crop diseases in recent years. In the current study, potato leaves were foliar-sprayed with chitosan and phosphorus to assess their ability to induce PVY resistance. Compared to untreated plants, the findings demonstrated a significant decrease in disease severity and PVY accumulation in plants for which CHT and P were applied. Every treatment includes significantly increased growth parameters, chlorophyll content, photosynthetic characteristics, osmoprotectants (glycine betaine, proline, and soluble sugar), non-enzymatic antioxidants (glutathione, phenols, and ascorbic acid), enzymatic antioxidants (peroxidase, superoxide dismutase, lipoxygenase, glutathione reductase, catalase, β-1,3 glucanase, and ascorbate peroxidase), phytohormones (gibberellic acid, indole acetic acid, jasmonic acid, and salicylic acid), and mineral content (phosphorus, nitrogen, and potassium), compared to infected plants. However, compared to PVY infection values, CHT and P treatments showed a significant decrease in malondialdehyde, DPPH, H₂O₂, O₂, OH, and abscisic acid levels. In addition, increased expression levels of some regulatory defense genes, including superoxide dismutase (SOD), ascorbic acid peroxidase (APX), relative pathogenesis-related 1 basic (PR-1b), and relative phenylalanine ammonia-lyase (PAL), were found in all treated plants, compared to PVY-infected plants. Conclusion: Phosphorus is the most effective treatment for alleviating virus infections.

Water deficit is a significant environmental stress that has a negative impact on plant growth and yield. In this research, the positive significance of kaolin and SiO₂ nanoparticles in moderating the detrimental effects of water deficit on maize plant growth and yield is investigated. The foliar application of kaolin (3 and 6%) and SiO₂ NPs (1.5 and 3 mM) solutions increased the growth and yield variables of maize plants grown under normal conditions (100% available water) and drought stress conditions (80 and 60% available water (AW)). In addition, plants treated with SiO₂ NPs (3 mM) demonstrated increased levels of important osmolytes, such as proline and phenol, and maintained more of their photosynthetic pigments (net photosynthetic rate (PN), stomatal conductance (gs), intercellular CO₂ concentration (Ci), and transpiration rate (E)) than with other applied treatments under either stress or non-stress conditions. Furthermore, the exogenous foliar application of kaolin and SiO₂ NPs also reduced the amounts of hydroxyl radicals (OH), superoxide anions (O₂), hydrogen peroxide (H₂O₂), and lipid peroxidation in maize plants experiencing a water deficit. In contrast, the treatments led to an increase in the activity of antioxidant enzymes such as peroxidase (POX), ascorbate peroxidase (APX), glutathione peroxidase (GR), catalase (CAT), and superoxide dismutase (SOD). Overall, our findings indicate the beneficial impact of the application of kaolin and silicon NPs, particularly the impact of SiO₂ NPs (3 mM) on managing the negative, harmful impacts of soil water deficit stress in maize plants.

Agriculture faces many challenges because of climate changes. The nutrients present in nano-sized form improve plant productivity, especially when used at the appropriate planting time. Field experiments were conducted as a factorial experiment for evaluating two planting dates (20th September and 20th October), foliar application with nanoparticles (NPs) including silica nanoparticles (SiO₂-NPs) at 1.5 and 3 mM, calcium carbonate nanoparticles (CaCO₃-NPs) at 5 and 10 mM and distilled water (control) on pre- and post-harvest characteristics of Dahlia pinnata var. pinnata Cav. The results indicate that the interactions during the late planting time (20th October) and exogenous applications of SiO₂-NPs at 1.5 mM or CaCO₃-NPs at 10 mM have improved plant growth including plant height, stem diameter, fresh and dry weights of plant, leaf area, inflorescence diameter, inflorescence stalk length, branches number, tuber numbers, inflorescences number on the plant, and the vase life. At the same time, insignificant differences appeared in the interaction during the planting dates and SiO₂ or CaCO₃ -NPs concentrations on inflorescence stalk diameter, total soluble solids, membrane stability index, maximum increase in fresh weight (FW), and Si and Ca contents. In addition, all exogenous applications of NPs at the late planting time promoted the plant growth characteristics like lignin %, cellulose %, inflorescence water content, change in FW, and total water uptake. Moreover, the controls through the two planting dates recorded the maximum change in water uptake and water loss values. In short, it can be recommended to use SiO₂-NPs at 1.5 mM or CaCO₃-NPs at 10 mM as a foliar application at the late planting time (20th October) for obtaining the optimum quantitative and qualitative parameters of D. pinnata .

A field experiment was carried out at the Experimental Farm of Soils and Water Department, Faculty of Agriculture, Al-Azhar University, Cairo, Egypt, to study the effect of two organic types of amendments (biochar: 2.5 and 5 ton/fed, compost: 5 and 10 ton/fed, and their combinations) on soil characteristics and the productivity of faba bean and wheat crops. Results revealed that the sole applications of organic amendments, either biochar (T1: 2.5 and T2: 5 ton/fed) or compost (T3: 5 and T4: 10 ton/fed), improve water and nutrient retention as well as enhance plant growth and yield of faba bean and wheat as compared to the control treatment (T0). Furthermore, the mixed applications of biochar and compost, especially with the increase in application rates (T5:T8), further improved the soil's physical and chemical properties than the single ones at T1:T4. Results showed that the relative increases in available water values over control treatment under different treatments of biochar and compost (T1, T2, T3, T4, T5, T6, T7, and T8) reached 5.16, 10, 7.26, 12.74, 15.32, 26.61, 31.77 and 36.61% for soil planting with faba bean while, the corresponding values for soil planting with wheat were 5.07, 10.29, 7.03, 12.58, 14.54, 18.46, 22.88 and 28.76%, respectively. Also, the highest mix of two organic amendments at 5-ton biochar and 10-ton compost per fed recorded the highest significant values of macro and micronutrient availability in soil and their content in straw and grains of faba bean and wheat plants.

A pot experiment was conducted to study the combined effect of fertilization (organic and inorganic sources) under irrigation levels of 100% (I1) and 80% (I2) of field capacity on clay soil properties, growth parameters, water use efficiency (WUE), and nitrogen uptake efficiency (NUE) by faba bean (Vicia faba cv. Giza 843). Findings demonstrated that, in comparison to the control, the interaction impact of fertilization treatments and irrigation levels significantly improved soil organic matter, cation exchange capacity, and reduced the values of soil bulk density. Additionally, N3 treatment (50% N from chicken manure + 50% N from urea) @ 100% of field capacity gave the highest relative increase in plant height (cm), number of branches per plant, fresh weight (g pot-1), dry weight (g pot-1) and chlorophyll value, which recorded 21.24, 52.63, 42.50, 38.87, and 31.60%, respectively. Also, compared to a single application of urea (N1) or ammonium nitrate (N4), integrated organic and inorganic fertilizers @ N3 followed by N6 (50% N from chicken manure plus 50% N from ammonium nitrate) recorded the greatest significant values of NPK content and uptake. Principal component analysis (PCA) showed that the most studied soil properties, growth parameters, WUE, NUE and nutritional status of faba bean correlated with the treatments of N3 and N6 under both irrigation levels.Therefore, the integration between organic and inorganic fertilizers under good irrigation management becomes essential to enhance plant growth and improve soil properties and sustainability.