This study was carried out during three successive seasons of 2010/2011, 2011/2012 and 2012/2013 in a private orchard at 76 km Cairo, Alex. Desert road  to investigate the effect of nitrogen and potassium fertilization treatments and shading with white net on yield, and fruit quality of three-years-old mango (Mangifica indica L.) cv. Keitt grafted on sucary seedling rootstocks planted at 2.5×2.5 meters apart grown in sandy soil under drip irrigation system with wells water .This experiment included nine treatments of fertilization: T1= N 80+ K2O 80 Kg/Fed., T2= N 80+ K2O 100 Kg/Fed., T3= N 100+ K2O 80 Kg/Fed., T4= N 100+ K2O 100 Kg/Fed., T5= N 120+ K2O 80 Kg/Fed., T6= N 120+ K2O 100 Kg/Fed.,T7= N 150+ K2O 80 Kg/Fed., T8= N 150+ K2O 100 Kg/Fed. and control (T9) = N 133+ K2O 90 Kg/Fed.. The results cleared that mango Keitt cv. trees grown under white net shading condition significantly increased yield (kg)/ tree, number of fruit set/ panicle, fruit weight, TSS and ascorbic acid content. Trees supplied with 150 Kg/Fed. nitrogen + 100 Kg/Fed. potassium exhibited the highest yield (kg)/tree, number of fruit set/panicle and  fruit weight under shade . Moreover, the best fruit peel color was achieved with trees received 100 kg/feddan of nitrogen +100 kg/feddan of potassium and grown under screenhouse conditions during the three studied seasons. The higher significant value of acidity and TSS were recorded in trees supplied by 120 units of nitrogen + 100 units of potassium during first and third season. Whereas, the control treatment attained a maximum ascorbic acid content.

From an eco–economic perspective, the efficient use of nitrogen is becoming incrementally worthwhile in crop management. Therefore, growth, yield and seed yield response index of three sesame varieties (Shandwel–1, Giza–32 and Sohag–1) as affected by four N rates (0, 72, 108 and 144 kg N ha−1) were investigated during two seasons of 2013 and 2014. The study illustrated that Sohag–1 was the superior variety for achieving SPAD value and seed yield ha−1. Sesame plants can be fertilized with N at a rate of 108 kg ha−1 being recorded higher seed yield ha−1. Integration between proper variety as a genetic factor with the appropriate N rate applied as an environmental one, i.e. Sohag–1 x 108 kg N ha−1 (or Sohag–1 x 144 kg N ha−1) considered a marked practice for gaining high sesame seed yield as an economic product. Being Sohag–1 exhibited less reduction in yield under low N rate and highly response with high N applied it belongs to ER group.