Two field experiments were carried out during 2016 and 2017 consecutive seasons at a Private Farm at Mit-Ghamr Distrect, Dakahlia Governorate, Egypt, to study the effect of humic acid rates (0.0, 325.60, 651.2 and 976.80 g/fad.), NPK fertilization rates [0.0, 25, 50, 75 and 100% of the recommended rate (RR)] and their interactions on growth, leaves and herb yield and some chemical constituents as well as active ingredients of stevia plants. The obtained results referred that the maximum value for each of plant height, branch and leaf number/plant, total dry weight/plant, dry weight of leaves and herb/fad., total N, P, K and total sugar percentages as well as total chlorophyll content (a+b) were detected when plants were applied with the highest rate of humic acid (976.80 g/fad.) and fertilized with 75% RR of NPK, in most cases. The main constituents of Stevia rebaudiana leaves as detected by high performance liquid chromatography-mass spectrometry (LC-MS) were Rebaudioside A, Rebaudioside B, Rebaudioside C, Dulcoside and Steviolbioside which increased with treatment of 100% RR of NPK fertilizers combined with the highest rate of humic acid (976.80 g/fad.) compared to control.

Two field experiments were carried out at a Private Farm named Royale herbs in Elbawiti Village, El Wahat El-Bharia District, Giza Governorate, Egypt during the two consecutive seasons of 2016/2017 and 2017/2018 to study the effect of different fertilizer types (mineral, organic and bio fertilizers) treatments on vegetative growth, yield components and volatile oil as well as total carbohydrates percentage of chamomile plant. The performance of organic fertilization (compost and humic acid) and biofertilization (nitobein or/and phosphorein) were compared with standard, commercial rates of N, P, K and Mg fertilizers with respect to the growth, yield and essential oil of Matricaria chamomilla. In the two successive seasons, plants treated with chemical fertilization showed a significant increase in vegetative growth (plant height, number of branches per plant, fresh and dry weights per plant) compared to the other types of fertilizers under study. The highest rate of chemical fertilizers (N, P 2 O 5 , K 2 O and MgO at 125, 100, 62.5 and 30 kg/faddan, respectively) recorded the highest value in each yield component (flower heads number per plant as well as flower heads air-dry weight per plant and per faddan) compared to the other ones under study, in most cases. In the same time, organic fertilization (30 m 3 compost + 1 kg humic acid/ faddan) recorded an increase in these yield components compared to the other organic fertilizer rates in both seasons. Also, fertilization at (1 kg of nitrobein + 30 m 3 compost/faddan) recorded a significant increase in volatile oil percentage of chamomile plant compared to either of sole chemical or biological fertilizer rates under study.

Governorate, Egypt during the two consecutive seasons of 2015 and 2016 to study the effect of different soil salinity levels (0.0, 1500, 3000 and 4500 ppm), lithovit rates (0, 2, 4, 6 and 8 g/l) as foliar applications and their combination treatments on growth, yield components and some chemical constituents of cluster bean (guar) plants. The investigations were performed in a split-plot in complete randomized block design with 3 replications. The obtained results cleared that using salinity levels decreased growth parameters (plant height, number of branches /plant and dry weight of leaves/ plant), yield components (pod number and seed yield/plant), some chemical constituents (total chlorophyll content a+b) and active ingredient (galactomanan) compared to control. Moreover, the highest values in these parameters were registered by lithovit at 8 g/l treatment in both seasons, in most cases. Generally, it could conclude that lithovit at 8 g/l, showed a uniform impact in alleviating of cluster bean growth inhibition and its productivity under moderate salinity stress condition.

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