Two field experiments were carried out during two summer seasons of 2013 and 2014 years at the Experimental Farm of Kaha Station, Qalubia Governorate to study the effect of using three irrigation intervals (7, 15 or 21 day) and five treatments of water absorbent substrates as adding to soil before transplanting ,i.e. (without substrates (control), SAP at 15 kg/fed., SAP at 20 kg/fed., compost at 5 t/fed. and compost at 10t/fed.) on sweet  pepper plants c.v. Mohanad and the effect of that on growth, yield, physical and chemical characters of sweet  pepper fruits. The results indicated that, the highest values of all vegetative growth parameters, yield and yield components were registered by the treatment of 7 days or 15 day irrigation intervals. Concerning of using water absorbent substrates, it was found that, pepper plants grown in the soil fertilized at 10 t/fed. or treated with super absorbent polymer (SAP) 20 kg/fed., respectively gave the highest values of vegetative growth parameters, yield and yield components.It is obvious that the plants fertilized at 10 t/fed. and irrigated every 7 days gave the highest values of fruit length, fruit diameter, fresh fruit weight and total yield. While, plants treated with SAP at 20 kg/fed. and irrigated every 15 day gave the highest values of fruit diameter and fresh fruit weight, but the differences did not reach to significance level for fruit length and early yield in both growing seasons. On the other hand, compost at 10 t/fed., compost at 5 t/fed. and SAP at 20 kg/fed. with irrigation every 21 day were the best treatments for yield and yield components of pepper plants. Generally, it can recommend by using compost at 5 t/fed., or super absorbent polymer (SAP) at 20 kg/fed. with irrigation every 15 days and this mean that increased the irrigation period without any injury or statistical effect on the fruit crop to obtain high pepper fruit yield  with height quality and height net income to the growers.

Pot trials were conducted under plastic house condition during two successive seasons of 2013/2014 and 2014/2015, at the experimental site of Central Laboratory for Agricultural Climate (CLAC), Agricultural Research Center, Giza, Egypt. The present study aims to determine the partial replacement of mineral nitrogen fertilization of tomato by nitrogen fixing bacteria with or without adding compost in sandy soil. Tomato seedlings (Lora F1Hybrid) were transplanted during the first week of October into plastic pots (30 cm diameter) filled with 10 kg of sandy soil. Three rates 25, 50 and 75% of the recommended mineral nitrogen in the nutrient solution for tomato with adding compostat 2% and nitrogen fixing bacteria (Azotobacter chroococcum and Azospirillium brasilense) at 20 ml/plant either individually or in combinationswere investigated on growth, mineral composition and yield of tomato plants compared to 100% of recommended nitrogen only (control). The plants were irrigated daily by drip irrigation and received 200 ml/plant of nutrient solution twice a weekly. The results showed that using 50 or 75% of N-mineral fertilizer + compost + nitrogen fixing bacteria gave the highest values of growth, mineral composition and yield of tomato. It is recommended that 50% of nitrogen mineral fertilizers for tomato plants could be replaced by nitrogen fixing bacteria in presence of compost, which in earn, reduce environment pollution caused by extensive application of mineral nitrogen fertilizers.