الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Because organic farmers face major challenges in providing nitrogen from organic sources necessary for plant growth under organic farming, the current research aims to study the effect of organic fertilization on organic cucumber plants grown under plastic greenhouses in sandy loam soil, and then provide nitrogen in an appropriate quantity, method, and time with the aim of achieving the highest productivity and quality. Therefore, experimental trials were conducted on a private farm near Abu-Ghalib area, Cairo-Alexandria desert road, Giza governorate, Egypt during the 2021/2022 winter season. The study was done through three stages. First, vermicompost was prepared mainly using rabbit dung manure as a feeding material to grow earthworms. Second, two nutritional solutions were prepared using KOH. One of them is vermicompost tea and the other solution is pigeon manure tea. Third, a plastic greenhouse was chosen to grow cucumber plants (Cucumis sativus L., variety Barchouda F1).
Plant growth and yield parameters, in addition to chemically available -N in soil and total N% in plant tissue (the fifth leaf from growing tip) were estimated during different physiological stages and soil available P, soil available K and organic matter content after harvesting. The obtained results showed that the physical, chemical, and biological characteristics of the vermicompost organic materials were acceptable as indications of maturity. Also, pH, EC, C/ N ratio, total nitrogen, chemically available nitrogen, phosphorus, and potassium in soil reached acceptable values for plant growth. Also, matured vermicompost has appreciable quantities from humic substances, plant growth regulators and amino acids. The obtained results showed that the response of cucumber to application of full mineral N (Farmer practice), followed by the application of solid vermicompost and solid pigeon manure at different application rates in integration with vermicompost tea and pigeon manure tea injected through dripping irrigation system gave higher results of plant height, number of leaves/ plants, number of fruits/ plants, fruit length, total N% content in the 5th leaf of plant and fresh and dry weights of shoots and roots at 120 days from transplanting, total N% content in plant shoots and roots in compare with those treatments without prepared solutions. Additionally, the highest fruit dry matter and shelf life were obtained in plants treated with VCT and PgMT. Furthermore, the mean comparison of results showed that the highest fruit yield (kg plant-1) was produced with using mineral N (farmer practice), followed by the application of solid vermicompost and solid pigeon manure at different application rates in integration with VCT and PgMT. On the other hand, the lowest fruit yield obtained from plants untreated with the prepared solution.
Results indicated also that the application of solid vermicompost and solid pigeon manure in integration with vermicompost tea and pigeon manure tea showed a significant effect on soil available NPK and soil organic matter content after harvesting. The results of this research indicated that adding organic materials enhanced the performance of N in cucumber plants and soil fertility under greenhouses conditions. In conclusion, chemical fertilizers can be replaced, at least partially, with organic fertilizers produced at the lowest costs, and thus vermicompost tea is considered an effective and economically viable alternative compared to mineral fertilizers.