Assessment of Fourth Rule Irrigation on Sunflower-water Productivity in Clay Soils of North Nile Delta, Egypt

The field trial was conducted during the two successive summer sunflower seasons 2021 and 2022 at Sakha Agricultural Research Station (Egypt).in north of the Nile Delta. This work aimed to was to assess the suitability of the fourth rule irrigation in clayey soils. Obtained results revealed that front of irrigation water reaching the end of the cultivated furrows (Trt. A) is the most suitable surface watering such clayey soils. By executing that technique of Trt A compared with two, three and four folds of front irrigation time, several advantages could be achieved such as; high yields of seeds, oil and protein. Moreover, a pronounced amount of water saving as well as the highest values of water productivity (WP) of each unit of consumed water (WP) and/or productivity of irrigation water (PIW). Meaningfully, that fourth rule of irrigation is not suitable and applicable in irrigating the clayey soils of the middle north Nile Delta.