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ISSUE 2  May 10, 2001

 

LATE PLANTING AND CROP MATURITY

Since the 2001 planting season is off to a very slow start, being 10-14 days behind last year, readers may wish to note the approximate crop maturity differences. Below is a listing of the average days to physiological maturity of many crops grown in North Dakota. Early Killing frosts, plus extreme high temperatures at flowering time are the most limiting factors of high yields.

Crop

Days

Crop

Days

Barley
Oats
HRSW
Durum
Wheat
Field Peas
Corn
Canola
Mustard

70-85
82-98
83-98
85-100
85-95
90-110
85-100
85-100
80-95

Soybean
Sunflower
Dry beans
Proso Millet
Buckwheat
Sugarbeet
Triticale
Lentils
Crambe

95-110
90-110
90-110
70-90
70-80
frost
75-85
80-90
85-95

Time required for maturity varies with variety or hybrid, seeding date, geographic region and available growing degree days. A shortage of growing degree days can increase days required for maturity. Corn, soybean, sunflower and millet are especially sensitive. Relative maturities for major crop hybrids and varieties are listed in the respective NDSU variety performance circulars.

 

SOLID SEEDING CONFECTION SUNFLOWER

Research results of NDSU oilseed sunflower trials have shown yield differences between solid seeding and conventional row spacings (30"). In fact most NDSU research studies indicate higher yields of 5 to 25% with narrow rows compared to conventional row spacings. Higher yields were achieved with even stand establishment and good weed control. Also there havenít been any differences in other agronomic traits such as oil content, plant height, dry down, or test weight being reported.

What about confection sunflower? The most important concern for confection sunflower besides the yield is the impact of narrow rows on seed size and quality. Research was conducted on row spacing with confection sunflower at the NDSU North Central Research Center, Minot, ND.

Confection sunflower at 18,000 plants per acre at 4 row spacings, NDSU North Central Research Extension Center, Minot, ND 1996-97.

Row spacing

Lodging

Head diameter

Test weight

 
6 in
12 in
18 in
30 in

%

13.0
15.3
7.2
6.1

inch

12.4
11.5
11.7
12.7

lb/bu

27.8
27.5
27.4
27.3

 

- - - - - - - - Seed Size- - - - - - -

 

Row spacing

>18/64

>20/64

>22/64

Yield

 
6 in
12 in
18 in
30in

%

54
47
48
56

%

19
15
14
16

%

6
3
4
3

lb/ac

1689
1392
1646
1604

There were little if any differences between row spacings with head diameter, seed size, test weight, and yield. There is a trend that as row spacings narrow from 30 inches lodging increases. Plant population for confection sunflower in narrow rows should be similar to conventional row spacings, approximately 18,000 to 20,000 plants per acre. A good weed control program is essential. The most important consideration is even stand establishment which leads to proper drill calibrations. Calibration to minimize skips and doubles is very important. Keep in mind that the distance between seeds increases within the row as the row spacing decreases. An example would be a producer that conventionally seeds confections at 18,000 plants per acre in a 30-inch row would calibrate for an optimum distance of 10.5 inches between seeds in a row. Solid seeding a 7.5 inch spacing at 18,000 plants/acre would result in an optimum distance of 42 inches between seeds in a row.

Duane R. Berglund
Extension Agronomist
dberglun@ndsuext.nodak.edu

 

COMPENSATING FOR LATE PLANTING IN SMALL GRAINS

It is approaching mid May and planting progress is way behind. Questions are rolling in about when and how much to increase seeding rates on small grains. I want to discuss briefly why increased seeding rates would be considered.

Most every planting date study on spring seeded small grains indicates that delayed planting results in decreased yield. Why? Small grains are cool season crops and really donít like hot temperatures, especially during early vegetative periods of growth.

A wheat or barley plant that has an extended period of relatively cool (60į to 75į F) moist conditions between emergence and jointing will tiller and develop an extensive root mass. The more tillers a plant produces the greater the yield potential of that plant. If the plant is subjected to high temperatures during early growth fewer tillers are produced and the plant enters its reproductive stage in less time.

As planting is delayed the likely hood that a small grain crop will be subjected to hot temperatures during early growth increases. This can be compensated for in part by increased seeding rates. However, delayed planting will not always result in reduced yield. In some years hot temperatures do not occur until July, well after a small grain crop has flowered. This is most often true in years with a late spring like this year.

Now the question is, "When is late and how much should seeding rates be increased?" Because there is obvious variation from year to year an exact date of when seeding rates should be increased does not exist. If you see two different calendar dates from two sources, they are not necessarily conflicting. The date I consider as late is May 15. Typically small grains seeded after this date will yield less than when seeded earlier. To compensate for reduced tillering I generally recommend increasing seeding rates 1.5 percent for each day past May 15 a small grain crop is planted. If you are south of I94 you may want to start increasing seeding rates on May 10 and if you are north of US hwy 2 you may want to delay increasing seeding rates until May 20th. Increased seeding rates above 20% of normal should be the upper limit.

Keep in mind that as yield potential is reduced expected yield goals should be adjusted accordingly when figuring how much nitrogen to apply. This is especially true when raising malting barley. If your yield potential is reduced by 20% because of late planting and you apply enough nitrogen to meet your original yield goal the end result could very easily be high protein and loss of malt quality.

Another frequent question is, "Its late in the season, should I switch to a earlier maturing wheat variety?" Donít waste and extra day or two chasing down a different variety. The time lost finding a different variety will typically not justify the extra effort. If you have it on the farm it may provide a benefit.

Michael D. Peel
Small Grains Extension Agronomist
mpeel@ndsuext.nodak.edu


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