Two field experiments were conducted at Sids Agricultural Research Station Farm during 2010 and 2011 seasons to investigate the effect of two nitrogen fertilizer sources, namely ammonia gas (83% N) and urea (46.5% N) with three levels, i.e. 60, 90 and 120 kg N/fed as well as rock phosphate as phosphorus source under two levels (0.0 and 300 kg rock P/fed) on growth characters ,yield and its components,net income and N, P and K concentrations and uptake of maize (Zea mays L.) as well as soil fertility. The results show that 120 kg N/fed as ammonia gas recorded the highest values of plant height, dry weight/plant, ear length and diameter, 100-seed weight, grain and stover yields, net income, N, P and K concentrations and uptake and nitrogen availability, while number of rows and kernels/ear and P and K availability not affected by either nitrogen sources or levels. Application of rock phosphate significantly increased plant height, dry weight/plant, 100-seed weight, grain and stover yields, net income, N and P concentrations and N, P and K uptake as well as P availability, while ear length and diameter, number of rows and kernels, K concentration and the availability of N and K in soil after harvesting not affected. Phosphorus concentrations in both grains or stover and N and P availability in soil after harvesting were affected by increasing nitrogen levels only under ammonia gas application.

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Agricultural production in Egypt mainly depends on chemical fertilizers and the rates of their consumption, per unit area are more than the averages of the whole world. However, because of shortages in some fertilizers supplies, and currents costs of energy used in their production, the cost of fertilizers has risen tremendously and will continue rise. In view of the economical and environmental problems of using chemical fertilizers, utilization of ammonia gas and natural fertilizers, e.g. rock phosphate, feldspar and humic acid would not only resulted in increasing soil fertility and crop production through its additional nutrients supply, but would also help in solving sanitary and environmental problems, as well as would save foreign currency for Egypt.Humic acids mainly produced from nitrogenous compounds containing decomposed amino acids and aromatic complexes (Andriesse, 1988). Those organic complexes affect soil properties and physiological properties of plants due to carboxyl (COOH -) and phenolic (OH -) groups (Schnitzer, 1992). It enhances plant growth by chelating unavailable nutrients and buffering pH (Tahir et al, 2011). However, their effects on soil have not yet been clearly elucidated. In many studies, humic acids were reported to increase the uptake of mineral elements (Khaled and Fawzy, 2011), to promote root length (Canellas et al, 2002), to increase the fresh and dry weights of crop plants (Chen et al, 2004 and Akinci et al, 2009). Ulukan (2008) reported that humic acid had positive effect on wheat growth and yield and its components. Furthermore, Shahryari and Mollasedeghi (2011) found that humic acid decreased drought stress intensity and increased economic and biological yield of wheat.In Egypt, many authors reported the superiority of using anhydrous ammonia than other nitrogen fertilizers such as Morsy ( 1994), Abd El-Hamed et al, (1996), Ismail et al (1996), Abd El-Kader (2002), El-Masry et al (2006) and Siam et al (2008). There are several reasons why anhydrous ammonia is used so widely, first because anhydrous ammonia is the initial step in the manufacture of almost all commercial N and second it is the least costly source of fertilizers N. Also it contains the highest nutrient concentration (82.5% N). On the other hand, Rajan et al (1996), Hellal et al (2009), Massoud et al, ( 2009) and El Sheref (2012) indicated that direct application of rock phosphate and feldspar materials may be ergonomically more useful and environmentally more feasible than soluble P and K. Also, it improved growth, yield and chemical composition of plant as mineral fertilizers. They added that, the natural fertilizers reduce contamination which is caused by chemical fertilizers and produce healthy and safe plants, as well as the fact that natural fertilizers have less cost than chemical one.The objective of the present investigation is to evaluate the effect of some natural fertilizers, i.e. rock phosphate, feldspar and humic acid under two nitrogen sources, namely urea and ammonia gas on wheat productivity a...

Two field experiments were performed at Village No. 1, west of Samallote, Minia Governorate, Egypt during 2004Egypt during /2005Egypt during and 2005Egypt during /2006 seasons to study the effect of four levels of farmyard manure (0, 10, 20 and 30 ton/fed); NPK fertilization doses, (i.e. 0, low (60/15/24) and high (120/30/48) kg of N, P2O5 and K2O/fed) and the micronutrients (Fe, Mn, Zn and Cu) which were applied, soil application or as foliar spraying on N, P, K, Fe, Mn, Zn and Cu uptake by wheat plants (Sids 1 cv) grown on a sandy soil and their availability in soil. The results could be summarized as follows;Uptake of N, P, K, Fe, Mn, Zn and Cu by wheat plants significantly increased with increasing rate of the applied FYM and NPK, as well as the micronutrients application, where foliar spraying surpassed soil application in both seasons.The soil availability of N, P and K responded to manuring only. However, phosphorus only significantly increased by increasing NPK fertilization.Soil available contents of Fe, Mn, Zn and Cu were significantly affected by manuring and micronutrients as soil application, while foliar spray did not affect contents of these micronutrient in both seasons.It could be concluded that wheat under sand soils should be fertilized with 30 ton FYM/fed; NPK at rate of 120 kg N, 30 kg P2O5 and 48 kg K2O/fed. Also, the micronutrients should be applied to improve both nutrients uptake by wheat plants and their availability in soil.

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