Water Use and Yields of Sugarbeets Over a Range from Excessive to Limited Irrigation

Abstract

AbstractWater use and sucrose yield of sugarbeets (Beta vulgaris L. cv. USH 10) as a function of decreasing water applications were investigated to determine if sucrose yield per unit of water use would increase with limited irrigation. The sugarbeets were fall‐planted in a silty clay soil and irrigated uniformly for 6 weeks to establish seedling stands and to wet soil to the 152‐cm depth. Thereafter, 102 mm water was applied whenever cumulative ET from sugarbeets growing in an adequately watered weighing lysimeter reached 91, 102, 112, 122, 133, or 143 mm water. Soil was sampled to the 152‐cm depth, in 30.5‐cm increments, before each irrigation after 12 November and at harvest. Water use was calculated from changes in soil water content between irrigations and applied water.Water applications, after the initial uniform applications, varied from 609 to 940 mm in six to nine irrigations plus 25 mm rainfall. Water use was linearly related to lysimeter ET. During differential treatment, water use varied from 11% above to 23% below the amount needed to replace lysimeter ET. Total seasonal water use varied from 900 to 1,195 mm. Lysimeter ET averaged 67% of pan evaporation after leaves completely covered the soil. Neither sucrose content nor yield was affected by irrigation treatments. Sucrose yields averaged 13 and 18 metric tons/ha on 14 May and 24 June, respectively. With limited irrigation, sucrose yield per unit of water use increased as much as 22% above the treatment that matched lysimeter ET. The soil salinity did not increase sufficiently to require immediate leaching for any of the treatments.