Corn Product Response to Irrigation and Population

Trial Overview

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  • 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.
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Research Objective

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  • 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.
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Location
Soil Type
Previous Crop
Tillage Type
Planting Date
Harvest Date
Potential Yield
Planting Rate
Battle Creek, NE
Loamy sand
Soybean
Reduced tillage
05/14/2016
10/08/2016
 
 
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Site Notes:

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Eight DEKALB® brand corn products were planted at 24K, 30K, 36K, and 42K (K = 1,000) seeds/acre (s/a) under 100% full irrigation (100% FI) and 75% of full irrigation (75% FI).  The trial was irrigated with a center pivot system with drop nozzles placed above the crop canopy. Rainfall = 10.3 inches, 75% FI = 7.25 inches, and 100% FI = 9.8 inches. The trial was intended to be a comparison of 100% FI verses 50% FI; however, due to variable rate irrigation equipment failure on July 30, subsequent irrigation events were all at 100% FI, resulting in a rate closer to 100% FI verses 75% FI at the end of the season. The amount of irrigation applied per pass prior to July 30th was 0.70/0.35 inches (100% FI/50% FI treatments, respectively).At planting, the site had approximately 3.5 inches of plant available water in the top 3 feet of the soil profile. The site received approximately 1.5 inches of rainfall in June, 2.5 inches in July, and 1.5 inches in August.Corn products and planting rates were replicated three times under the 75% FI and 100% FI treatments.Weeds were controlled and very little lodging was observed prior to harvest.
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Understanding the Results

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Table 1. Yields by corn product, planting population, and irrigation treatment at Battle Creek, NE
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  • Averaged across all products and planting populations, yields were 19.3 bu/acre higher for the 100% FI treatment than the 75% FI treatment.
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  • Averaged across all planting populations, DKC62-77RIB brand blend had the lowest yield response (5 bu/ac) between the 100% FI and 75% FI treatments, while DKC59-50RIB brand blend had the highest yield response (37.8 bu/ac).
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  • Increasing the planting population from 24K to 30K seeds/acre provided the largest yield increase across most products at either irrigation treatment.
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  • In the 75% FI treatment, DKC60-67RIB, DKC60-88RIB, DKC63-60RIB, and DKC64-34RIB brand blends yielded the highest at 30K seeds/acre, yields of DKC58-06RIB and DKC61-54RIB brand blends peaked at 36K seeds/acre, and yields of DKC59-50RIB and DKC62-77RIB brand blends were maximized at 42K seeds/acre.
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  • In the 100% FI treatment, DKC60-88RIB and DKC61-54RIB brand blends yielded the highest at 30K seeds/acre, yields of DKC62-77RIB, DKC63-60RIB, and DKC64-34RIB brand blends peaked at 36K seeds/acre, and yields of DKC58-06RIB, DKC59-50RIB, and DKC60-67RIB brand blends were maximized at 42K seeds/acre.
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What Does This Mean for Your Farm

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  • Producers should carefully consider corn product selection and planting rate based on the irrigation capabilities in each field to maximize their return.  
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  • While yield typically increases with increased irrigation, producers should consider the costs of applying extra water against the potential profits from increased yield, especially when yield-limiting conditions occur.
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  • These data suggest that the planting population should be at least 30K seeds/acre, even at reduced irrigation levels, as there is a consistent yield and profit penalty with under-planting, regardless of product selection.
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  • Monsanto intends to continue these trials to evaluate corn product response to irrigation level and population under changing environmental conditions for the 2017 season.
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