Two trials were carried out at the Experimental Station farm of Desert Research Center, Teggzerty from Siwa Oasis, Matroh Governorate during the two summer seasons, 2015 and 2016. Trials were performed to study response of two maize hybrids.(Single hybrid 131 and Triple hybrid 329) to organic manure (OM) levels (15 and 30 m3/fed.) and five combinations between mineral and nano nitrogen (N) fertilizers: 1)100% mineral N from the recommended dose (120 kg N/fed.), 2)75% mineral + 25% nano N fertilizers, 3)50% mineral + 50% nano N fertilizers, 4)25% mineral + 75% nano N fertilizers, 5)100% nano N as the recommended rate (500 ppm as foliar application). Mineral N rates were added in three equal doses, with foliar application by nano N rates, after 30, 45 and 60 days from sowing. Treatments, included twenty treatments, was laid out in a splilt-split plot design, with three replicates, OM levels were arranged in the main plots, maize cvs. were allocated in the sub plots, and mineral nano N fertilizer treatments were assigned in the sub-sub plots. At harvest the following characters were recorded, plant height (cm), number of rows/ear, ear length (cm), ear diameter (cm), number of grains/row, 100-grain weight (g), ear weight (ton/fed), grain, straw and biological yields (ton/ fed), shelling (%) and harvest index(%). Results indicated that increasing OM levels significantly increased ear length harvest index and protein content (%), in the 2nd season only, triple hybrid gave the maximum values of all pa rameters, except no. of rows/ear and harvest index, in the 1st season, and 100-grain weight and carbohydrate (%), in both seasons, which had no significant difference with single hybrid in the most cases. Concerning with the effect of mineral and nano N, all parameters, except carbohydrate (%), were increased with increasing mineral N (%) and/or with decreasing nano N (%). Fertilized maize crop by mineral N at 100% or 75% plus 25% nano N fertilizer gave the maximum values of plant ht., no. of rows/ear, ear length and diameter, no. of grains/row, 100-grain wt.,ear weight, grain, straw and biological yields, shelling (%), protein (%), protein yield and harvest index in both seasons. However, fertilized maize crop by nano N at 100% produced the highest value of carbohydrate content (%) in two seasons. Results suggested that selected triple maize hybrid cv. (329), at 30 m3 OM, with 100% mineral N (120 kg N/fed.) or with 75% mineral N (90 kg N/fed.) plus 25% nano N (125 ppm as foliar application) fertilizers could be utilized for attaining the maximal improvement in farmer income by increasing the maize yield under saline conditions at Siwa Oasis, Egypt.

Late blight caused by Phytophthora infestans is one of the most destructive dis-eases potato in Egypt and world wide. Stability of resistance to late blight was eva-luated in twenty five potato cultivars during 2003 and 2004 successive seasons un-der heavy natural infection. Data showed that the potato cultivars Altesse, Occania, Safrane and Soleia highly resistant while cultivars Daisy, Hermine and Isabel rec-orded the highest susceptibility to late blight. Application different fungicide against potato late blight revealed that Aquagen Bro and Previcur-N were the best effective fungicides in reducing disease severity and progress of late blight. Data showed also that the losses of tubers due to late blight in season 2003 ranged from 11.75 Kg/plot (cultivar Hermes) to 18.0 Kg/plot (cultivar Lady Roseta) while in season 2004, yield losses ranged from 11.25 Kg/plot (cultivar Hermes) to 23.75 Kg/plot (cultivar Spun-ta). The results demonstrate that integration of Previcur-N treatment with host resis-tance was effective in reducing late blight and tuber yield loss of potato.

Two field experiments were conducted during the summer season of 2003 and 2004 to study the effect of organic and bio-organic fertilizers [esterna biofert, compost, biocompost and effective microorganisms (Em)] on vegetative growth, yield and physical and chemical components in tubers of local and fuseau Jerusalem artichoke cultivars. Results indicated that Em, biocompost and biofert significantly increased plant height, number of main and lateral shoots and dry weight as well as the concentrations of Chl (a+b), carotenoids and total carbohydrates in the leaves. Moreover, dry matter, inulin, nitrogen, phosphorus and potassium of tubers showed a significant increases. The highest vegetative growth and tuber yield were obtained when Em, biocompost and biofert were applied. The respective increase in lateral shoots, Chl (a + b), carotenoids, average tuber weight and size were higher in local cultivar. Whereas fuseau cultivar tubers showed greater dry matter than those of local variety. The application of Em, biocompost and biofert fertilizers in both local and fuseau cultivar gave the relatively higher yield with good quality.

Four olive cultivars namely Manzanello, Picual, Coratina and Arbicon grown at Wadi El-Natroon area, Egypt under drip irrigation system in sandy soil were compared for optimizing their own yield as well as fruit quality parameters during 2001 (off-year) and 2002 (on-year), by application of an integrated and balanced fertigaion program including macro and micro-nutrients. Results showed that remarkable and significant differences in leaf mineral contents, yield and yield quality parameters were detected by using well distributed fertilizer program during the growing season of olive trees. The treated four cultivars attained higher yield in the “on” and “off” year than the control. The most outstanding olive cultivars having greater yield were Picual, Manzanello, Coratina and Arbicon in a descending order. Oil percentage was maximized with Picual olive while, Arbicon olive had the lowest value. Free fatty acids (%), Iodine number as well as Acidity (%) were minimized in Coratina olive and the lowest peroxide number as was in Picual olive. It is apparent that for planting Picual olive variety proved to be the promising one due to its greatest yield and best fruit quality specially when the actual requirements of macro and micro nutrients were used through the drip irrigation system.