ISSUE #473

473 - Coping With Excess Rainfall


Comprehensive Drainage Plans The Answer

Excessive growing season rainfall is becoming commonplace in Eastern ND and Western MN. Overland flooding, standing water in depressional areas and saturated soils have caused serious sugarbeet losses almost every year since 1993 in some parts of the Red River Valley. Crop losses will be severe in parts of several counties in 2005.

Drainage Objectives and Benefits

  • 473.1Earlier planting
  • Better stand establishment
  • More uniform fields
  • Less plant disease
  • Improved sugarbeet storage
  • Reduced soil compaction
  • Improves ability to harvest
  • Better utilization of water
  • Increased crop production
  • Less power required for field operations
  • Controls surface water runoff without erosion
  • Increased revenue per acre

Drainage Maps

A successful drainage improvement plan must remove excess water efficiently to reduce crop damage and improve yields. New RTK technologies enable growers to make detailed topographic maps with sub-centimeter accuracy. They show field elevation, depressions, field watersheds and water flow paths that clearly define problem areas in a field. Then drainage maps can be successfully prepared.

Drainage Calculator

American Crystal has a drainage calculator that will assist in determining how much crop production and revenue you are losing from inadequate drainage of your fields. Using satellite images to create a drainage map will show the number of acres per zone by reflectance value that is under producing (low value= poor drainage) in each year of crop rotation.

  • The calculator shows the value of improving inadequately drained portions of the field.
  • Drainage maps utilize prior years satellite imagery
  • Puts a value to a field with drainage problems
  • Not a stand alone drainage tool

 Fig 2. Excess water causes sprangling     Fig 3. Leveling fields

473.2 473.3



Subsurface tile drainage is an alternative to consider. Tile drainage is costly but has proven successful for some Red River Valley farmers.

Assistance Available

Your Agriculturist can assist you with field drainage plan development. Make plans now to collect data during grain harvest.

Cercospora Information

Check out NDAWN and for the latest daily infection value information.

Tiling Facts


  • Increases crop revenue
  • Less crop variation
  • More timely planting
  • Reduces soil erosion
  • Reduces Phosphate loss
  • Improves water qualityv


  • Increased Capital costs $350-$500/A
  • Increases soil infiltration
  • May transport Ag chemicals
  • Can reduce water table


Late Season Weeds Threatens Some Fields

Late season weed competition is more apparent in 2005 than anytime in the last 5 years. Left uncontrolled these weeds will cause yield loss, harvesting difficulty and sugar losses in storage piles.

Why Late Season Weeds In 2005

  • Uncontrolled late germinating weeds
  • Less crop competition in fields with poor stands
  • Problems maintaining spray schedules around rain events
  • Weed escapes from POST herbicides

Late Season Weed Control Options

  • Hand labor
  • Mowers, shredders, cutter bars
  • Defoliators
  • Over the top chemical application (Roundup is not legal to apply this way)
  • Electrical discharge system

University of Nebraska Research - Dr. Robert Wilson

Tall weeds including corn, sunflower, Kochia and Lambsquarter at one weed per 5 feet of row competed with beets. The study treatments were, hand labor, mowing and Roundup all applied on August 3 and August 17. Results were as follows:

  • Uncontrolled weeds reduced yield by 41%
  • Hand labor gave 94% weed control and maximum yields of 24T/A
  • Allowing weeds to grow two extra weeks before the mowing treatment reduced yield by 23%
  • Roundup controlled weeds, but reduced stands by 49% and root yield by 51%
  • Cutting weeds twice in early and mid-August reduced yield loss from 10 ton per acre to 2.3 tons

Late Season Weed Control Results at NDSU/U of MN

Dr. Alan Dexter and graduate students Richard Evans and Dennis Rasmussen conducted similar research in the 1970's and 1980's. A summary of results follows:

  • Over the top Roundup reduced stand by 14 to 34% and yield by 50 to nearly 75%
  • Hand weeding reduced stand by 4-8%
  • Hand weeding increased yields by 300 to 900 lbs. RSA
  • The electrical discharge system gave 500 to 700 lbs/A RSA yield increase
  • Mowing early gave greater yield increase than later mowing in July
  • Mowing short increased yields more than mowing higher
  • Hand labor gave best control of late season weeds and best yield increases

The best control at the lowest cost for late season weeds is most likely to mow them in late July or early August and a second time in mid to late August.

Contact your Agriculturist for assistance with late season weed control.