Phosphorus is one of the essential macronutrient element not only for rice but also for other plants, it is important for plant metabolism and enzymatic activity during the periods of growth and grain filling. Rice growth, yield and its attributes strongly influenced by phosphorus nutrition. This investigation was conducted to study the performance of different rice genotypes i.e. Sakha105 and Sakha106 (japonica), Giza178 (indica/japonica) and Giza182 (indica) under four phosphorus levels namely 0, 18, 36 and 54 P2O5 ha -1 . This study was carried out at Experimental Farm of Rice Research and Training Center during both 2010 and 2011 growing seasons. At harvest, plant height, number of panicles m -2 , panicle weight, panicle length, number of filled grains panicle -1 , number of unfilled grains panicle -1 , 1000 grain weight, grain and straw yield were determined. After harvest, N and P content of rice grain and straw were measured as well as hulling, milling, head rice and amylose percentages were assessed. The obtained results revealed that the rice genotypes were significantly differed in their response to phosphorus application according to genetic background. indica or indica/japonica genotypes responded up to 54 kg P2O5 ha -1 without significant differences with 36 kg P2O5 ha -1 more than japonica type which responded up to 18 kg P2O5 ha -1 . Application of phosphorus fertilizer up to 36 kg P2O5 ha -1 improved rice growth traits i.e. plant height and panicle length as well as grain yield and its attributes. Combination of Giza178 with 36 kg P2O5 ha -1 produced the highest grain yield followed by Giza182 with the same levels of phosphorus. Application of phosphorus fertilizer up to 18 kg P2O5 ha -1 gave the maximum grain yield of Sakh105 and Sakha106. Concerning grain quality traits had positive significant effect with increasing phosphorus levels.

and 2015 seasons, to study the effect of sowing date (15 th of April, 1 st of May and 15 th of May) on grain yield of twenty rice genotypes, and infestation by Rhizopertha dominica (F.). Sowing date had significant effects on all studied characters in both years. The highest values of number of panicles per hill, number of filled grains per panicle, grain yield, hulling, milling and broken rice grain were recorded in the early sowing date. The number of days from seeding to maturity and number of unfilled spikelets per panicle were recorded in the decline trend, as sowing was delayed. Egyptian Hybrid Rice 1 produced the highest values of grain yield followed by Giza179, and Giza178. Sakha106 produced maximum values of hulling and milling percentages. Regarding to the susceptibility of rice varieties to insect infestation by lesser grain borer, R. dominica in storage, data showed that the

A field experiment was conducted during the two successive summer seasons of 2009 and 2010 in using clayey soil at the farm of Rice Research and Training Center, Sakha District, Kafer El-Sheikh Governorate, Egypt, to investigate the effect of rice straw incorporation in the soil under continuous flooding and continuous saturation on availability of some nutrients in the soil (ammonium, nitrate, phosphorus and potassium) and rice yield. Utilization of 165 kg N ha -1 gave the highest values of rice grain yield but without any significant differences with 5 tons rice straw ha -1 + 110 kg N ha -1 . The largest amounts of nutrients (NH4 + and P) availability were found with continuous flooding. While, the highest values of NO3 and K availability were found under continuous saturation. The continuous flooding treatment gave more grain yield as compared with continuous saturation treatment.

Phosphorus is a macronutrient that plays number of important roles in plants. It is a component of nucleic acids, so it plays a vital role in plant reproduction, of which grain production in an important result. Intensive cropping system, high phosphorus consumer crops, high yielding rice varieties and high soil pH restricted P availability resulted in low rice yield. The experiment was carried out at farm of Sakha Agriculture Research Station, Kafrelsheikh during 2014 and 2015 summer seasons, in clayed alkaline soil, the study aimed to find out the effect of different levels of phosphorus fertilizer on yield and yield attributes of rice in low soil phosphorus. The treatments consist of four cultivars; Egyptian hybrid rice one (EHR1), Sakha102, Sakha106 and Giza179 and five phosphorus (P) fertilizer levels Viz. 0, 12, 24, 36 and 48 kg P 2 O 5 . ha -1 as single super phosphate (15.5 % P 2 O 5 ). Split plot experiment design with four replications was used. At heading some growth parameters were measured yield and yield attributes were estimated. Nitrogen and phosphorus uptake were determined.The studied varieties were certainly differed regarding their yield and yield attributes as well as nitrogen and phosphorus uptake. The Egyptian hybrid rice one (EHR1) apparently surpassed others studied varieties in growth, grain yield and most of yield components characteristics.All the studied parameters of rice varieties differed significantly with the application of phosphorus fertilizer. Plants grown without added phosphorus gave the lowest grain yield. The higher phosphorus levels exhibited higher grain yield. A significant interaction between varieties and phosphorus levels in respect of yield and yield attributes of rice were observed. The highest grain yield was recorded with Egyptian hybrid rice one at 48 kg P 2 O 5 . ha -1 .It could be concluded that high yielding rice varieties, EHR1 and Giza 179 responded to phosphorus fertilizer up to 48 kg P 2 O 5 /ha -1 . Furthermore, the medium yielding varieties; Sakha102 and Sakha106 performed better with P level of 36 kg P 2 O 5 /ha -1 . The application of phosphorus for rice after heavy phosphorus consumer crop and high pH soil is imperative to fetch high rice grain yield.

The present research was conducted to study the influence of organic and inorganic sources of nutrients as well as antioxidant on rice quality. The experiment was designed in split-split plots with four replications, where main plots were assigned to nitrogen (0, 55, 110 and 165 kg N ha−1) and sub plots were allocated to compost (0, 3.5 and 7 tons ha−1), while the sub-sub plots were assigned to ascobien (control, spraying with ascobien in two times at 15 and 30 days after transplanting (DAT), spraying with ascobien three times at 15, 30 and 45 DAT). The result indicated that grain quality traits were significantly influenced by the organic and inorganic fertilizers, and ascobien. The percentage of hulling, milling and amylose were positively and significantly influenced by nitrogen, organic and antioxidants application. Most of studied characters produced the highest values with the organic fertilize were combined with nitrogen and antioxidants. Application of 110 kg N ha−1, 7 t ha−1 compost and two or three spraying of ascobien, 110 kg N ha−1 or 3.5 t ha−1 compost and three times spraying and 55 kg N ha−1, 7 t ha−1 compost and two times spraying could be recommended for optimum grain quality of Sakha106 rice variety. It can be concluded that compost along with the foliar application of ascobien can be saved from 50 to110 kg N ha−1, without reducing grain quality. It can be the key to reduce the need for chemical fertilizers and decrease the cost of production with keeping healthy soil.