Idaho Crops & Soils: Sugar Beets Research Update

Nitrogen and Water Management for Optimized Sugar Beet Yield and Sugar Content

Principal Researchers: Olga Walsh and Sanaz Shafian

Affiliation: Olga Walsh, University of Idaho

Address: 29603 U of I Lane, Parma ID 83660; (208) 291-6218

Principal Contact Email: owalsh@uidaho.edu

We are grateful to the Snake River Sugarbeet Research and Seed Alliance LLC and the Amalgamated Sugar Company for funding and supporting this project.

INTRODUCTION

Sugar beet (SB) production profitability is based on maximizing three parameters: beet yield, sucrose content, and sucrose recovery efficiency. Efficient nitrogen (N) and water management are key for successful SB production. Nitrogen deficits in the soil can reduce root and sugar yield. Overapplication of N can reduce sucrose content and increase nitrate impurities which lowers sucrose recovery. Application of N in excess of SB crop need leads to vigorous canopy growth, while compromising root development and sugar production. Changes in SB varieties and management practices warrant re-evaluation of N management. TASCO and the USDA-ARS found that in 60% of evaluated SB fields, application of N did not increase sucrose yield. This suggests that residual soil N from past applications and in-season N mineralization was adequate and indicates that growers could maximize sugar yield and save money by applying less N. Due to recommendation to have all N applied and plant-available by 4-6 leaves, it is imperative to determine the appropriate N application rates for N responsive fields early in the season. Appropriate irrigation amount and timing can optimize SB yields while minimizing disease pressure, water costs and N leaching. Excessive irrigation can increase SB root weight, but lower sugar content. Defining the optimum water and N fertilizer levels should be done on a regional basis, utilizing locally grown varieties and taking into account local management practices. Remote sensing is a promising tool for in-season N and water management and in-season prediction of SB yield and quality, which in turn can improve the economic returns to SB growers and processors. Crop sensors can accurately measure SB biomass production and top N content. Spectral indices are correlated with N rates applied to SB can be used for in-season prediction of SB yield and quality and to make N management decisions.

List of Objectives

The goal is to improve water and N use efficiency for agronomically, economically, and environmentally sustainable SB production by combining traditional and novel, state-of-the-art methodologies.

1. To analyze the effects of water and N fertilizer rates on SB yield and quality,

2. To explore the potential of using ground- and aerial-based (UAVs) data for SB N and water content monitoring,

3. To access the feasibility of predicting SB root yield and recoverable sugar using hand-held and UAV-based sensors, and

4. To conduct extension outreach focused on water and nutrient management in SB, remote sensing, and UAV use for crop monitoring.

Sugar beet planting, April 18, 2019