Enhancing Water-Limited Corn Success After 2012 Drought

Enhancing Water-Limited Corn Success After 2012 Drought

April 12, 2013

As we get close to planting corn (and I write this watching the snow fall in mid-April), it is a good time to make management decisions for the upcoming planting season. While many have probably made up their minds and several prior CropWatch articles on seeding rate and water management have already give some insight, it would be prudent to keep in mind that these recommendations are based on the best information we have available. In the case of planting rate and planting date recommendations, these come from previous data.

While using past data is critical for success, it should be used cautiously as a reference point. Even data from last year—a year in which many, if not all, of our dryland producers suffered yield loss due to drought—may not be a good reference point for decision making if we see the same in-season conditions this year. As the writer George Santayana wrote, those who fail to learn from history, are doomed to repeat it. But I'd like to note: those who fail to think critically about history, also are doomed to failure.

Last year we started the season with a fairly good soil moisture profile in most of the state. Unfortunately, we are not as fortunate this year. Many growers with no restrictions on water allocations are or are considering the use of pre-irrigation prior to planting to start to build the soil moisture profile. Many who have irrigation restrictions are considering crops other than corn.

For many though, neither of these are good options, either due to lack of irrigation, restrictions on irrigation, or an inability to switch to a different crop due to a variety of reasons (e.g., marketing and contracts to seed availability). If you're planning to grow corn under dryland or reduced water allocation conditions, Table 1 may be helpful in determining corn population. (This table is from the NebGuide, Recommended Seeding Rates and Hybrid Selection for Rainfed (Dryland) Corn in Nebraska, G2068.)

The recommendations are still very good, but do keep history in mind. Last year there was good soil moisture at planting for these populations. This year the soil moisture profile is much lower and the risk of yield failure going into the season is much greater.

Lastly, growers should remember that the recommendations are generic. Every grower should consider these factors along with their own experience as elevation, soil type, temperatures (air and soil), crop rotation, irrigation availability and capacity, residue, and other agronomic input decisions can vary greatly across the state. Each of these factors will play a role in the success of this year's crop.

Greg Kruger
Extension Cropping Systems Specialist, West Central REC


Table 1. Suggested harvest populations for moisture and residue conditions at planting on silt loam soils in Nebraska. Even distribution of residue is assumed.

Area
Mid-Season Corn (skip-row)
Short-Season Corn (skip-row)

With 2,000 lb/ac wheat residue or 4,000 lb corn/sorghum, or 55% residue cover and 2 feet of subsoil moisture.
Western
-------------------------- Do not plant corn --------------------------
Central
12,000
(11,000)
13,000
(12,000)
Eastern
16,000
(15,000)
17,000
(16,000)
 
3,500 lb/ac wheat residue or 7,000 lb corn/sorghum or 90% residue cover and 4 feet of subsoil moisture.
Western
10,000
(9,000)
11,000
(10,000)
Central
14,000
(13,000)
15,000
(14,000)
Eastern
18,000
(17,000)
19,000
(18,000)
 
5,000 lb/ac wheat residue or 100% residue cover and 6 feet of subsoil moisture.
Western
12,000
(Same)
13,000
(Same)
Central
15,000
(Same)
16,000
(Same)
Eastern
20,000
(Same)
21,000
(Same)

  1. 100 lb of residue are produced for each bushel of winter wheat and 50 lb of residue are produced for each bushel of corn or sorghum produced.
  2. For continuous no-till, the residue could be a combination of the winter wheat residue and corn or grain sorghum residue.
  3. Requires equipment that can plant or drill through residues.
  4. Long-season corn hybrids are not recommended. If used, reduce plant population.