الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The high costs of nitrogen fertilizers are necessitating bestdeveloped practices to optimize nitrogen fertilizer use whilst minimizing nitrogen losses. Ammonium adsorption inhibits loss of nitrogen thereby increasing nitrogen availability for crops. So, a pot trial was performed aiming at evaluating the effect of soil addition of natural zeolite [ Z0 : without zeolite Z1: 1% of zeolite and Z2 : 2% of zeolite ] as a combined treatment with different rates of various nitrogen sources [0.0 (without nitrogen fertilizer as control treatment), 50 and 100 % of NRD using ammonium sulfate, urea and ammonium nitrate] on the characters of jew’s mallow plants ””cultivar Balady”” at different stages of plant life as well as some soil properties at seed harvest stage. The results obtained could be summarized as follows : 1 - Periods of 50 and 80 Days from Sowing. 1.1- Vegetative growth criteria. The combination effect among zeolite rates and N treatments was significant, where the highest values of jew’s mallow growth parameters i.e. foliage fresh and dry weights (g plant-1), leaves weight (g plant-1) and plant height (cm) at two different period ; the first cut time (after 50 days from sowing) and the second cut time (after 30 days from the first cut) during seasons of 2020 and 2021 were recorded when jew’s mallow plants grown in pots contained 2% of zeolite and fertilized with 100% of NRD as ammonium sulfate, while the lowest values are realized when jew’s mallow plants grown without both zeolite and N fertilizers. On the other hand, the combined treatment of 2% zeolite and 50% of NRD (in SUMMARY AND CONCLUSION 50 any studied N-form) gave results better than treatment of 100% of NRD (in any studied N-form) without zeolite. 1.2- Chemical constituents in leaves. the values of chemical composition of jew’s mallow foliage i.e. N, P, K (%), Fe (mg kg-1) and photosynthetic pigments ( chl. a, chl. b and carotene, mg.g-1 FW) took the same trend of growth criteria, where the highest values were realized with jew’s mallow plants grown in pots received 2% of zeolite and fertilized with 100% of NRD as ammonium sulfate, while the lowest values were realized when jew’s mallow plants grown without both zeolite and N fertilizers. On the other hand, the plants received 2% zeolite and 50% of NRD possessed values of all aforementioned chemical traits better than that received 100% of NRD without zeolite. 1.3- Quality parameters. The quality parameters of jew’s mallow i.e. total phenol, VC (mg 100g-1(, TSS (%) and NO3 (mg kg-1) at two times (after 50 and 80 days from sowing) during both investigated seasons significantly differed as a result of studied treatments, where the combination of 2% zeolite + 100% of NRD as ammonium sulfate resulted in significant increase in the quality parameters of jew’s mallow over all other combined treatments. While, the lowest values were recorded with control treatment (without both zeolite and N fertilizers). On the other hand, the combined treatment of 2% zeolite and 50% of NRD gives results better than treatment of 100% of NRD without zeolite under all studied N fertilizers. 2- Seeds Harvest Stage. 2.1- Seed yield and its components. The combination effect among zeolite rates and N treatments was significant, where the highest values of seed yield and its components of SUMMARY AND CONCLUSION 51 jew’s mallow plants i.e., No. of branches plant-1, No. of pods plant-1 and seeds weight g plant-1 were recorded when plants grown in pots contained 2% of zeolite (equivalent to 200g 10kg-1 soil) and fertilized with 100% of NRD as ammonium sulfate, while the lowest values are realized when jew’s mallow plants grown without both zeolite and N fertilizers. 2.2- Soil properties. Cation exchange capacity (CEC, cmol kg-1) : The soil CEC valuesincreased as zeolite rate increased. Available nitrogen (mgkg-1): The average values of soil available N at harvest of jaw’s mallow plants pronouncedly increased over that before jaw’s mallow cultivation. It was noticed that soil addition of zeolite amendment clearly increased available N in soil. Also, the soil that received N fertilizers possessed available N at harvest more than that without N fertilizers. On the other hand, the lowest values of available N in the soil after harvest were found with soil received ammonium sulfate fertilizer followed by that received ammonium nitrate and lately, that received urea fertilizer. Regarding the rate of N fertilizer, the highest values of available N in the soil after harvest were found with soil received 100% of N fertilizer followed by that received 50% of N fertilizer. Total porosity (TP,%) : Mixing zeolite with soil found in pots before sowing led to increase soil total porosity, where its values increased as zeolite rate increased. Electric conductivity (EC, dSm-1) : soil EC values pronouncedly increased due to applying zeolite as compared to untreated soil (without zeolite), thus it can be said that zeolite increased soil salinity, where soil EC values increased as zeolite rate increased as well as all studied N SUMMARY AND CONCLUSION 52 form at different studied rates led to increase EC value compared to corresponding soil untreated. Generally, soil addition of zeolite before sowing improved all studied soil properties except EC, where the values of fertility parameters (CEC, porosity and available N) as well as EC of soil pronouncedly increased as the rate of zeolite increased.