investigation the effect of surface and subsurface drip irrigation methods and irrigation interval on yield quality and quantity of cotton

given the scarcity of water resources using modern methods of irrigation in agriculture will be inevitable. today, process improvement, development and use of drip irrigation practices as one of the most advanced methods of irrigation in agriculture is increasing. so this study was conducted to determine the impacts of irrigation interval and drip irrigation method and their interactions on yield, water use efficiency and quality characteristic of cotton in kashmar agricultural research station, khorasan razavi province. the study was carried out during 2006-2008. experimental design was a completely randomized design with four replications. treatments were included irrigation intervals (2, 4 and 6 day) and drip irrigation methods (surface and subsurface drip irrigation). the results showed that the irrigation methods had significant effect on yield and water use efficiency (p≤ 0.01). there was significant difference between yield in surface and subsurface drip irrigation that was 3074 and 3988 kg/ha, respectively. water use efficiency was 0.349 kg/m3 in subsurface drip irrigation that was greater than surface drip irrigation. the highest yield and water use efficiency in drip irrigation and subsurface irrigation 4 days, 4315 kg/ha and 0.375 kg/m3 respectively and the lowest with 2 days 3107 kg/ha and 0.265 kg/m3, respectively. yields in irrigation intervals of 2, 4 and 6 days were 3491, 3725 and 3364 kg/ha, respectively, with no significance difference. the highest water use efficiency and yield were obtained in subsurface irrigation method with 4 days interval as 4315 kg/ha and 0.375 kg/m3 respectively, while the least water use efficiency and yield was obtained in surface irrigation method with 2 days interval as 3107 kg/ha and 0.265 kg/m3, respectively. finally, using subsurface drip irrigation with irrigation every 4 days was chosen as the best treatment.