Responses of Sugarbeet to Deficit, High-Frequency Sprinkler Irrigation. II. Sugarbeet Development and Partitioning to Root Growth1
- An N. Hang and
- D. E. Miller2
The water requirement of sugarbeet (Beta vulgaris L.) has been studied extensively throughout the western states. However, there is limited information about the response to prolonged deficit irrigation, particularly on sandy soils with low water-holding capacity. The present study was conducted to determine the effect of deficit, daily sprinkler irrigation on rates and growth characteristics of sugarbeet grown on loam and sandy soils (Xerollic Camborthids and Xeric Torripsamments, respectively). On loam soil, irrigation rates less than estimated evapotranspiration (Et) did not significantly affect the leaf blade petiole or top/root ratio until 4 to 8 weeks after they were initiated. Afternoon wilting of leaves was observed at the 15, 17, 39, and 41% Et irrigation rates, but they regained turgor during the night. After about 8 weeks of 15 and 17% Et irrigation rates specific leaf weight increased significantly. Top and root growth rates increased as the amount of water applied increased. Partitioning to root growth was maximum (75.8%) at irrigation rates equivalent to about 58% estimated Et. On sandy soil, irrigation rates less than estimated Et depressed growth, and shortened leaf life cycle. Leaf blade petiole and top/root ratio were not affected until after 6 weeks of deficit irrigation. Low irrigation rates depressed leaf expansion and resulted in very high specific leaf weights. Top and root growth rates increased with water application up to rates equivalent to 100% estimated Et. Maximum partitioning to root growth of 74.4% occurred at 100% irrigation rate. Increasing irrigation to 115% estimated Et gave no increased benefits. In both soil types, leaf blade petiole and top/root ratios were generally affected later and much less by drought than were leaf area, specific leaf weight and crop growth rate.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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