الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The scarcity of freshwater resources for agricultural purposes has led to a search for solutions to raise the efficiency of irrigation water use. Due to the population increase in the
world, the demand for food is increasing day by day, and then the demand for fertilizers is also increasing. There is also an urgent need to raise the efficiency of the use of fertilizers added to various crops and to follow a policy of not polluting the environment from the use of mineral fertilizers, which made many researchers turn to use what is now known as nano-fertilizers in
fertilization. One of the requirements of sustainability at present is to follow production methods for fertilizers that are environmentally friendly on the one hand and to apply the least amount of addition rates to obtain the optimum yield. One of the sustainability strategies is also
to work on recovering the nutrients present in agricultural waste to maximize the benefits of recycling agricultural waste.
Several methods were used to extract silicon from rice husk in the form of nano silicon by converting husk into rice husk ash or rice husk biochar first, then extracting nano silicon
from it and identifying the properties of nano silicon by TEM and FTIR. The second objective is to add N-Si either through foliar spray or add it to soil where wheat plants grow in the
greenhouse under water stress conditions to identify the role of N-Si in improving growth and yield under drought conditions (irrigation at rates of 100%, 60%, and 40% of WHC of soil).
The rice husk was brought from one of the rice mills of the New Burj Al Arab
and was prepared to obtain rice husk ash through air burning at temperatures ranging from 400:700℃ for times up to 12 hours or to obtain rice husk biochar through anaerobic burning (pyrolysis) and at temperatures ranging from 450:700℃ for times up to 12 hours. Biochar was
also obtained by using an Anila burner, whose burning temperature ranged between 350 and 500℃, for the time of 24 hours.
The silicon nanoparticles were extracted using alkaline solutions of sodium hydroxide or potassium hydroxide whose concentration ranged between 1:2.5M and using hydrochloric acid or nitric acid with concentrations similar to alkaline solutions.
Wheat was grown in pots containing calcareous soil that was obtained from the Banger El-Sokar (Village #2), Alexandria, Egypt. The plants were exposed to water stress after 38 days
of planting. The application of water stress was accompanied by the addition of N-Si at rates of zero, 150 and 300mgL-1 of N-Si either sprayed on the shoot or added to the soil in the form of potassium silicate and compared with commercial potassium silicate. All treatments were carried out in three replicates. Factorial completely random statistical design was used.
Some of the yield parameters were measured, such as spikes height, number of spikes, number of tellers, plant weight, grain weight, and root weight. The concentration of nutrients
such as nitrogen, phosphorous, potassium and silicon in dry shoots, roots.
The results obtained from silicon nanoparticles extracted from rice husk ash and biochar showed a difference in the extracted quantities depending on factors such as burning
temperature, burning time and type of extraction solution. The amount of nano silicon extracted by the anaerobic burning method increases with the decrease in the pyrolysis temperature,
where we obtained approximately 30.54% nano silicon (65.36% SiO2) from the biochar obtained from the Anila stove, the pyrolysis temperature ranged from 350:500℃ for 24hours and extracted with sodium hydroxide solution and approximately 32.45 % nano silicon (69.44% SiO2) with potassium hydroxide solution.