VRI - Corn Product Response to Irrigation and Population - Mingo, KS and Bethune, CO

Trial Overview

  • With the increase in limited irrigation due to reductions in pumping capacity or restrictions on the amount of water producers are able to pump over a certain period of time, it is imperative that Monsanto tests products under varying irrigation rates to supply better corn product recommendations by irrigation level.

Research Objective

  • The objective of this study was to determine the yield response of key DEKALB® brand corn products for the region based on planting population and irrigation amount.
Soil Type
Previous Crop
Tillage Type
Planting Date
Harvest Date
Potential Yield
Planting Rate
Mingo, KS
Silt loam
Strip tillage
250 bu/acre
24K, 30K, 36K, and 42K
Bethune, CO
Silt loam
Strip tillage
250 bu/acre
24K, 30K, 36K, and 42K

Site Notes:

Ten DEKALB® corn products were planted at 24K, 30K, 36K, and 42K (K = 1,000) seeds/acre (s/a) under 100% full irrigation (100% FI) and 50% of full irrigation (50% FI).The yield goals were 250 bu/acre for the 100% FI treatment and 190 bu/acre for the 50% FI treatment.Corn products and planting rates were replicated three times under the 100% FI and 50% FI treatments.Each location was irrigated with a center pivot system with nozzles placed within the crop canopy.For the Mingo, KS site: rainfall = 12.0 inches, ET = 29.0 inches, 50% FI = 6.3 inches, and 100% FI = 11.0 inches.For the Bethune, CO site: rainfall = 18.0 inches, ET = 24.0 inches, 50% FI = 5.0 inches, and 100% FI = 8.0 inches.The Mingo location had slight hail damage at the V8 growth stage.



Understanding the Results

  • In all products averaged across both locations, the yield for the 100% FI treatment was greater than the yield in the 50% FI treatment and the yields also increased with greater planting densities.
  • Across planting rates, the long-season products (106 RM and above) out-yielded the early-season products (105 RM and below) by 27.6 bu/acre under the 100% FI treatment and 8.7 bu/acre in the 50% FI treatment.
  • Late-season standability was assessed in all products through a push test. Standability was higher under the 100% FI treatment than in the 50% FI treatment, but stalk strength decreased as the populations increased.
  • Under 100% FI, yield was maximized or plateaued at 36K seeds/acre for most products. The highest yields were achieved with DKC60-67RIB, DKC64-34RIB, and DKC56-45RIB brand blends. Under 50% FI, where lower populations are desired, DKC55-84RIB, DKC60-67RIB, DKC63-21RIB, and DKC64-34RIB brand blends provided the highest yield per thousand (YPT) at 24K to 30K seeds/acre.

What Does This Mean for Your Farm

  • Farmers should carefully consider corn product selection and planting rate based on the irrigation capabilities in each field to help maximize their return.
  • While yield typically increases with increased irrigation, farmers should weigh the cost of applying extra water against the potential profits from increased yield, especially when yield-limiting conditions occur.
  • Monsanto intends to continue these trials to evaluate corn product response to irrigation level and planting population under changing environmental conditions for the 2018 season.