Document Type : Research Paper
Authors
1
Department of Water Engineering, Sari Agricultural Sciences and Natural Resources University
2
Assistante Professor, Cotton Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran
3
Professor, Department of Water Engineering, Sari Agricultural Sciences and Natural Resources University
4
Professor, Water Engineering Department, Sari Agricultural Sciences and Natural Resources University
5
assistant professor, Golestan agricultural and natural resources research and education center
Abstract
In order to investigate the effect of different methods, levels and salinity of irrigation water on cotton, a two-year experiment was carried out at the Hashemabad Cotton Research Station in Gorgan city. The experiment was performed in a randomized complete block design with three replications. So, four salinity levels of irrigation water (1, 4, 8, 12 dS/m) as main factors, four different levels of irrigation water (33, 66, 100 and 133% of water requirements) was considered as the first factor and two irrigation methods (complete irrigation and Partial Root Dry irrigation/PRD) were considered as the second factor. The results showed that compared to control, cotton yield decreased by 41%, 22% and 19%, in 12, 8 and 4 dS/m salinity, respectively. The water use efficiency was reduced at rate of 30, 18 and 16 percent. As the salinity of irrigation water increased, the average weight of the boll, fiber index, earliness and the fibers decreased significantly. As the moisture level increased, the yield of cotton, average boll weight, the number of seed in a boll and the number of bolls increased significantly. In additional the water use efficiency of the 133, 100 and 66% treatments compared to 33 percent decreased by 32, 16 and 10 percent, respectively. The cotton yield under133, 100 and 66% treatments decreased by 32%, 16% and 10%, respectively, compared to the 33% of the water requirement. Although PRD reduced crop yields by 15 percent compared to full irrigation treatment, but the water use efficiency increased by 36%.
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