Impact of Changing Irrigation Method and Planting Spacing on Water Productivity, Yield and Application Efficiency of Sugar Beet in Miandoab Plain

Sugar beet is one of the main products with high water requirement in Urmia Lake basin. Planting spacing and irrigation method of sugar beet has an important impact on increasing irrigation efficiency, crop yield and physical water productivity of this crop. In order to investigate the effect of planting spacing on irrigation efficiency, physical water productivity and crop yield, a field study was conducted on two pilot farms (A and B) in Miandoab irrigation network under farmer’s management during 2017. In this study a part of each farm was considered as control (common planting spacing and border irrigation) and the other part was considered as treatment (change the planting spacing and surface irrigation method from border to furrow irrigation). The control part of the farm included a low height groove inside the border and at 50 cm intervals (IA-C and IB-C) and the treatment part of each farm included two-row crop planting of sugar beet (so-called 40×60 cm: IIA-T and IIB-T) and furrow irrigation. According to the results, the maximum water application efficiency was obtained about 77.2% in IIA-T and the lowest efficiency was obtained about 10.2% in IB-C. The average irrigation efficiency (in 12 irrigation) in IIA-T and IIB-T were 54.5% and 51.1%, respectively and in IA-C and IB-C were 38.7% and 39.3%, respectively. Based on the results, by changing the planting pattern from common spacing to two-row (40×60) and irrigation method from border to furrow, the average water consumption reduced about 29.7% and the average yield increase from 64.3 to 74 ton/ha (increase by 15.2%). Also, the average physical productivity of sugar beet increased from 3.75 to 6.47 kg/m3 (increase of 2.71 kg/m3).