Water is the main limiting factor for agricultural expansion in arid and semi-arid regions as well as Egypt. So two field experiments were carried out during 2015 and 2016 summer season at the experimental farm of Sakha Agricultural Research Station, Egypt to enhance water productivity of rice using irrigation intervals, transplanting methods and weed control treatments. Strip split-plot design with three replicates was used in infested weedy soils. Irrigation intervals were in the horizontal plots, it was irrigate every three days as a farmer practices (I 1), every six days (I 2) and every nine days (I 3). Transplanting methods were located in vertical plots contained; transplanting in flat soil as a traditional method (M 1) and transplanting in bottom of raised-bed (M 2). While weed control treatments were assigned in sub-plots, it was penoxsulam (Granite) 24% SC (W 1), penoxsulam + orthosulfamuron 50% WG (Kelion) (W 2), thiobencarb50% EC (Citron) fb penoxsulam (W 3), weedy check (W 4) and hand weeding twice (W 5). Results showed that treatment of I 1 was the best in weed management, rice dry weight, number of panicles/m 2 , number of filled grain/panicle, 1000-grain weight and grain yield. Irrigation treatments of I 2 and I 3 saved about 20.7 % and 29.9 % of irrigation water compared to I 1 , while the highest productivity of irrigation water (PIW) were recorded by treatment of I 2 compared to I 1 and I 3. The lowest fresh and dry weights of total weeds and the highest values of rice dry weight, number of panicles/m 2 , number of filled grains/panicle, 1000-grain weight were recorded by M 1 as compared to M 2 , in addition rice grain yield of M 1 was increased by 7.1 % compared to M 2 as mean of the two growing seasons. Transplanting method of M 2 saved about 21.2 % of irrigation water and increased PIW by 18.4 % compared to M 1. The best weed management beside the highest values of number of panicles/m 2 , number of filled grain/panicle, 1000-grain and grain yield of rice were obtained by W 3 compared to rest weed control treatments and it take the descending order W 3 > W 5 = W 2 > W 1 > W 4 in the two seasons of study. The interaction of I 2 X M 1 X W 3 was superior treatment for rice grain yield. But, under shortage of water, increasing irrigation water productivity of rice could be achieved by the superior interaction of I 2 X M 2 X W 3 because it resulted in the highest irrigation water productivity of rice to be 0.98 kg m-3 .

This study was conducted at the Experimental Farm of rice department, Sakha Agricultural Research Station, Egypt during 2015 and 2016 summer seasons to investigate the effect of recommended doses from Stomp (pendimethalin 50% EC) and Rainbow (penoxsulam 2.5% OD) herbicides on weed control, microbial activities and rice productivity under drill-seeded rice cultivation. Total bacterial count, N 2 -fixing bacteria, N 2 -fixing cyanobacteria, nitrifiers and sulfate-reducing bacteria were counted at different periods of crop growth. Dry weight of Echinochloa crus-galli, Echinochloa colona, Ammania baccifera and total weeds were measured at 45 and 60 DAS. Paddy rice dry weight at 45 and 60 DAS, number of panicles, panicle weight and grain yield were determined. The results revealed that total bacterial count, nitrogen-fixing bacteria, native N 2 -fixing cyanobacteria and nitrifying bacteria were increased with penoxsulam application, while sulphate reducers were decreased in both seasons compared with application of pendimethalin and the untreated control. Penoxsulam application significantly decreased dry weight of Echinochloa crus-galli, Echinochloa colona and total weeds. While increased rice dry weight, number of panicles/m 2 , panicle weight and grain yield of rice in the two growing seasons.

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