ISSUE #511

511 - Cultivation and P Use in 2009


The first Roundup Ready® beet crop has raised numerous questions about how to manage it. Concerns have been rates and timing of Roundup applications, tank mixes with herbicides and insecticides, and impact of environment on weed control. The need to cultivate has also been much discussed. Very high fertilizer costs are also a subject of many conversations. Agriculturists have provided answers to most of these questions in a timely manner.

Will cultivation increase yield and quality of the 2008 crop?

The need to cultivate answer is YES if:

  • Weed escape competition could reduce yield
  • Weed escapes are thought to be herbicide tolerance or resistant
  • Light textured (sandy) soil surfaces have been sealed off by heavy rains
  • Dust reduced Roundup weed control

The need to cultivate answer is NO if:

  • Few or no weeds could be controlled with cultivation
  • Occasional weed escapes are not considered tolerant or resistant to herbicides
  • Fields have heavy soils that crack on drying - next rain infiltrates
  • Cultivation causes ruts and harvesting difficulty
  • Rhizoctonia has been a problem in the field


No Need to Cultivate Roundup Ready® Sugarbeets

Dr. Alan Dexter evaluated the need to cultivate Roundup Ready® and Liberty Link sugarbeets in 1997, 1998 and 1999. The data for Roundup Ready® trials is shown in the table below.

Influence of cultivation on yield of Roundup Ready® sugarbeets at 5 locations from 1997-1999

Number of CultivationHarvest PopulationSugar (%)Yield (T/A)RSA (lbs)
0 127 15.3 23.4 6254
2 122 15.1 23.7 6208
5 119 15.2 22.6 5938
  • Cultivation reduced stand significantly at 4 of 5 locations
  • Percent sugar was not effected in any year
  • Tonnage was significantly reduced at 2 of 5 locations
  • RSA was significantly reduced at 2 of 5 locations
  • Cultivated sugarbeet never resulted in a significant increase in revenue per acre
  • Research was conducted on Wheatville loam and Fargo clay soil types.

Starter Fertilizer (Banded Phosphorus) Leads the Way in Promoting Emergence and Early Plant Growth

The dual advantage of Banded Phosphorus is increased revenue per acre and lower fertilizer costs. Fertilizer savings could be $20/acre in 2009. Yield increases up to 1 ton/acre.

Research Conducted at NWROC by Dr. Al Sims and Dr. Larry Smith in 1999-2003

  • 3 gallons of 10-34-0/acre applied in-furrow gave maximum root yields.
  • Additional broadcast Phosphorus was not needed
  • 45 to 60 lbs/acre of 18-46-0 were required to maximize yields
  • Research conducted on both low and high Phosphorus testing soils