CORN AS AN ALTERNATE CROP FOR EASTERN WASHINGTON

 

Brian Lewis, Field Agronomist

Pioneer Hi-Bred International, Inc.

CCA, America Society of Agronomy

 

Adopting a new crop can be complicated by many factors such as varying soil types, topography and weather conditions. Over the past two years, a group including growers, Pioneer Hi-Bred, the McGregor company, Monsanto, Washington State University and extension have evaluated non-irrigated ("dryland") corn in eastern Washington.

We were fortunate to have two quite different growing seasons during this effort. In 1996, we experienced a cold spring followed by extremely hot temperatures in the summer. In 1997 we experienced a bit more heat during the spring but did not have the extreme temperatures of July and August the preceding year. 1996 corn yields were lower when compared to 1997. Ideal conditions for corn would be a warm spring with normal rains followed by a moderate summer, then a dry October.

Can dryland corn become a successful crop in eastern Washington? Here are some things to consider to make corn successful on your farm:

TILLAGE SYSTEM

It is not the intent of this paper to discuss the practice of no-till, as this will be handled by other speakers. However, moisture conservation is important in growing any dryland crop, and corn is no exception. A no-till system conserves moisture more efficiently than any other tillage system. No-till has its greatest advantage on farm land that is well drained, sloping, and free of severe compaction. No-till is likely the best tillage system for growing corn successfully in eastern Washington.

ROTATION

The practice of no-till has been most successful under a diversified crop rotation. A diversity of crops, unlike similar specie crops, breaks disease, insect and weed cycles. Spring barley is a cool season grass like wheat. Corn, a warm season grass, is quite different. Corn would offer two distinct advantages over spring barley in the rotation. First, Take-all, Rhizoctonia root rot and Cephalosporium stripe are three cereal diseases not hosted by corn. Winter annual grasses which host soil-borne pathogens of wheat and barley are more easily controlled in corn than spring cereals. Second, corn also has a different growing season than barley, which allows improved weed control options, especially on winter annual grasses, through cultural practices and herbicides.

PLANTING DEPTH

A seeding depth of 1½ inches and a firm seed bed are the goals in achieving optimum corn stands. Deeper seed placement (2½ inches or more) may cause emergence delays while shallow seeding depths (one inch or less) may allow the seed to dry out. When seeding is too shallow, secondary roots are set closer to the soil surface. This makes the corn plant more susceptible to drought. Also, pheasants and mice may find seed more easily when corn is seeded shallow.

Under no-till conditions, soils are wetter at planting time than with other tillage systems. Side-wall compaction can be a problem in wet soils. Fluted coulters and spoked press wheels can be used when planting to mitigate side-wall compaction. Applying pre-plant fertilizer on 30-inch centers under the seed row can aid in breaking up compaction and provide a good seed growing environment. This practice is successful in the Midwest.

PLANTING DATE

Planting dates can affect corn yields significantly. Generally, earlier planted corn yields better than corn planted later. With earlier planting dates, corn grows during the cooler part of the season when moisture stress is less likely.

Corn seed germination and growth will not occur until the soil temperature is 500 F. or higher. If planted too early, corn germination can be delayed to where it becomes susceptible to insect and pathogen invasion. Significant stand losses can occur from these pests.

Most of our corn strip trials in eastern Washington over the last two years have been planted during the first two weeks in May. Are earlier planting dates possible? I think a reasonable goal is April 20 to 25 for warmer regions like Walla Walla, and May 1 to 7 for colder regions like St. John, Washington. Again, these recommendations are based on two years of observations. These recommendations could change with future observations and data.

CORN HYBRID SELECTION

Corn hybrid selection is important. Hybrids vary in their response to the environment. Key traits for corn hybrids under a dryland system are stress tolerance, early growth, maturity and yield potential. Corn hybrids need to mature properly, requiring realistic planting and harvest dates. Hybrids requiring too full a season will not mature until late in the fall and carry unacceptable grain moisture levels. Hybrids bred for a very short season, on the other hand, may not achieve optimum yields.

Hybrid maturity can affect the water use efficiency of dryland corn as much as stress tolerance. Some shorter season hybrids may yield more than fuller season hybrids because they reach the critical flowering stage earlier in the season when temperatures are typically cooler. Early growth is an important agronomic trait. However, stronger early growth does not correlate to higher corn yields. Early growth becomes more important when corn faces challenging seed bed conditions. That is why conducting strip trials each year with hybrids of varying maturity and agronomics is important for properly evaluating potential hybrids for an area.

Data from the last two years indicates that in most areas of eastern Washington, 75 to 82 CRM hybrids seem to maximize our growing season, and they potentially pollinate before the hottest part of the summer. The table below compares Pioneer® brand hybrid 3970, a 77 CRM hybrid, to other hybrids of equal and longer maturity. Notice 3970 has a slight yield advantage over fuller season hybrids over the last two years.

Table 2. Pioneer 3970 compared to other hybrids in eastern Washington for the two year average(1996, 97).

Pioneer 3970 Compared to 3970 Yield Compared to Yield 3970 Yield Advantage
3970 (77 CRM) 39K72 (75 CRM) 64.6 64.1 0.5 (11 comp.)
3970 3941 (82 CRM) 65.5 62.7 2.8 (12)
3970 3905 (87 CRM) 76.7 74.4 2.2 (8)

Pioneer 3970 was 4.3, 0.3 and 1.3 points drier in grain moisture than 3905, 39K72 and 3941 respectively.

What a difference one year can make. The following table shows yields for various hybrids for 1996, 1997, and the two-year average.

 

Table 2. Corn yields in bushels per acre for 1996, 1997, and two-year average for selected hybrids in eastern Washington.

Hybrid 1996 1997 2-Year Avg.
39K72 (75 CRM) 31.0 82.3 57.1
3970 (77 CRM) 45.1 78.4 59.5
3941 (82 CRM) 46.2 75.8 63.1
3905 (87 CRM) 52.4 75.3 69.1
3893 (89 CRM) 51.7 74.7 67.0

 

PLANT POPULATION

Planting rates for the Dayton, Colfax and Walla Walla strip trial locations were approximately 21,000 seeds per acre for both 1996 and 1997. However, near Starbuck, Washington, a side-by-side, non-replicated population study was conducted. In this study, we compared two Pioneer hybrids planted at 15,000 and 21,000 seeds per acre. Table 3 shows there was a slight yield advantage for both hybrids to 15,000 kernels per acre versus 21,000.

 

Table 3. Hybrids 3970 and 3984 compared at two different plant populations. Yields are in bushels per acre. The tested area has an average 14 inches of annual precipitation.

Hybrid YLD @ 15K YLD @ 21K Advantage of 15K
3970 43.8 36.6 7.2
3984 39.8 37.8 2.0

 

Further testing will be needed to fine-tune plant population recommendations. For now, a good rule of thumb would be to drop 1,000 seeds per acre for every inch of average annual precipitation.

CORN HERBICIDES

Many herbicides are available for use in corn. However, in dryland no-till corn, some herbicides have limited use because of their soil incorporation requirement. Other herbicides may have limited use because of their rotational crop restrictions.

Wild oats, Russian thistle and some winter annuals can be troublesome weeds in corn. Banvel herbicide controls most broadleaf weeds when applied according to label recommendations. For wild oats and grasses, Accent herbicide performs well in no-till corn. Accent has a short rotation interval for most subsequent crops. Atrazine herbicide is another option for controlling wild oats and broadleaf weeds when growing continuous corn. Please refer to herbicide labels when selecting herbicides for your farm.

SOIL FERTILITY

What does dryland corn require for plant nutrients? EC 750, January 1996, Fertilizer Recommendations Guide, Cooperative Extension Service, South Dakota University, is an excellent publication to start with when determining fertilizer needs for dryland corn. Our 1997 corn trials received approximately 110 to 140# N, 20-30# P2O5, and 10-15# S per acre.

HARVEST

Corn harvest was accomplished with a John Deere combine provided by Tumac Machinery in Walla Walla, Washington. Most of the corn strip trials were harvested from late September to the middle of October. Some corn strip trials were harvested with a wheat head, but header loss can be high as 20% with that equipment. Yield losses are minimal when a corn head is used.

MARKETING

Marketing is the final step in evaluating the merits of a crop. Most growers are very interested in the agronomics of a possible new alternative crop (growth, herbicides, fertilizers, planting and harvesting dates). But for a moment, think in reverse. Consider first the local demand for the final product and the ease of marketing. Like wheat, corn is commodity crop and needs no special contract to market.

 

BUDGETING

The budget below attempts to analyze and estimate yield levels that may be required to make corn profitable in eastern Washington. This is an estimate of projected returns over chemical, fertilizer, seed and grain drying costs. Unknown yield potential and unforeseen factors could alter this estimate greatly.

 

 

DRYLAND CORN BUDGET

RETURN OVER FERT., CHEM., SEED, &

GRAIN DRYING COSTS IN $ PER ACRE

               

YIELDS IN BUSHEL/AC.

OR TONS/AC.

  BUSHELS  

40

60

80

100

120

  TONS  

1.1

1.7

2.2

2.8

3.4

               
PRICE $ /BUSHEL  

3.00

       
  /TON  

107.1

       
               
FERTILITY lbs./Ac.

22.50

32.50

42.50

52.50

62.50

Aqua-N $.28/lb.

N

48

72

96

120

144

P-10-34-0 $.50/lb.

P2O5

15

20

25

30

35

S-THIOS $.31/lb.

S

5

7.5

10

12.5

15

               
SEED    

11.90

14.90

17.80

20.80

23.80

YLD LEVEL

 

Seeds/Ac.

         

40 BU.

 

12,000

         

60 BU.

 

15,000

         

80 BU.

 

18,000

         

100 BU.

 

21,000

         

120 BU.

 

24,000

         
               
HERBICDE  

18.00

18.00

18.00

18.00

18.00

Pre-Plant: 3/4 lb. ai Atrazine. + 8 oz. Roundup          
Post emergent: 4 oz. Banvel + 1 pt. Buctril          
               
GRAIN DRYING  

5.60

8.40

11.20

14.00

16.80

22% MOISTURE            
$.02/PT./BU.            
               
TOTAL INPUT    

58.00

74.00

90.00

105.00

121.00

COSTS              
               
TOTAL    

120.00

180.00

240.00

300.00

360.00

INCOME              
               
RETURN OVER  

62.00

106.00

150.00

195.00

239.00

COSTS            

Conclusions

The ultimate goal in a cropping system is profitability.. Will corn be a profitable crop in your rotation system? The answer depends on several factors, as outlined.. We have learned a great deal the past two years about growing corn in eastern Washington. Potential for profitability appears favorable. However, expected yield potential still needs additional years of data and further study. What yields can you expect to achieve over various soils and conditions on your farm? We plan to conduct more strip trials over additional conditions and environments in 1998 and answer this question more fully and confidently.

Adopting a new practice or crop on your farm can be slow. Growers also need to evaluate the equipment needed to make a new enterprise successful. A corn head and planter are two pieces of equipment growers may need to purchase to grow corn successfully in eastern Washington. Using equipment other than that which is specifically recommended for planting and harvesting of corn has been largely unsuccessful.

Another factor to consider when evaluating corn as a rotational crop in eastern Washington is that it provides diversity in the crop rotation not available with current crops grown in this area. Also, corn is a commodity crop that requires no special contract.

The best thing a grower can do is use all the information that he has available to him. To stay in business in today’s rigorous farming environment, you must continually become more efficient. This may include evaluating new crops and determining their potential on your farm.