Determination of Alfalfa Water Productivity in Different Regions of Iran

In this study, volume of irrigation water, water productivity, and yield of alfalfa were measured in 300 farms in Zanjan, Fars, Chaharmahal and Bakhtiari, Hamedan, East Azerbaijan, Semnan, Khorasan-Razavi, Isfahan, West Azerbaijan, Central, Qazvin and Kerman provinces under farmers management and surface and sprinkler irrigation, various water sources, different water salinities, soil conditions, and varieties, during the growing season of 2018-2019. The results showed that the difference between average volumes of water applied by farmers, yield, and water productivity, in the studied sites were significant at 1% probability level. The average amount of applied water by farmers was 8502, 8901, 9226, 9459, 11481, 12796, 14311, 14821, 15198, 15916, 18351 and 23920 m3/ha, respectively, and the average was 13284 m3/ha. The dry yield of alfalfa varied from 2500 to 30000 kg/ha with an average of 13841 kg/ha. Irrigation water productivity varied from 0.2 to 4.5 and its average was 1.28 kg/m3. The average irrigation water plus effective rainfall productivity for alfalfa was 1.19 kg/m3. The results showed that the average applied water and alfalfa yield in surface and sprinkler irrigation methods were 15076 and 10653 m3/ha, respectively, (p<1%). These results showed that in sprinkler irrigation method, applied water was 30% less and irrigation water plus effective rainfall productivity was 41% higher. Accordingly, in order to reduce the volume of irrigation water and improve alfalfa water productivity, it is recommended to use sprinkler method in suitable climatic conditions where irrigation water is of good quality and the technical criteria of design, implementation, operation, and economic considerations are met.