ISSUE 3    May 18, 2006

FLAX PLANTING DATES

How late can flax be planted and still get fairly good yields? It was noted in the May 15, 2006 NASS-USDA Crop and Weather report that flax was only 38% planted in North Dakota. How late can we be planting flax and still have a reasonable yield for profitability? Below are research results from flax seeding date studies conducted and averaged over 9 years at the North Central Research Extension Center at Minot, ND.

Flax Seeding - Minot, ND

Seeding period

Average* Yield bu/A

% Early seeded date

1st (Early-May)

24

100

2nd (Mid-May)

22

93

3rd (Late-May)

18

79

4th (Early-June)

16

68

5th (Mid-June)

11

48

6th (Late-June)

4

16

Early June planted flax was 8 bu/A less than early May planted flax. These data suggest that all flax should be planted between late April to May 15 to ensure maximum yield potential. Good seedbed preparation, adequate shallow seed placement to moisture, weed control and fertility management also will contribute to high flax yields. Yield goals of 30+ Bu/A are not unrealistic for well managed flax production.  Any flax planted after the end of May perhaps is not economically feasible unless current prices or loan value is considerably higher.

 

NODULES ON FIELD PEAS

Field peas that have been emerged for 2 to 3 weeks should have nodules forming on root hairs of both the primary root and lateral roots. Nodulation is the symbiotic relationship of bacteria on the pea roots, can be seen and should be checked for healthiness of nodules. Healthy nodules actively fixing nitrogen for the plant are pink or red inside. White, brown or green nodules indicate that nitrogen-fixation is not occurring. If the pea plants appear yellow and the roots appear not to be nodulated, then its suggested to get the field top-dressed with nitrogen. Nitrogen fertilization after planting is not generally recommended as too high levels of nitrogen fertilizer applied can and will inhibit nodule formation and ability to fix N for the legume plant for later grain development and protein content of the seed. One really should let nature take its course and let the nodules fix the N for the growing legume plant.

When checking the health of nodules also check root proliferation, and look for any root rot diseases or insect damage. Diseased roots will have low nodule formation. Its also highly suggested to not physically pull the plants since root hairs will slough off along with the nodules you are checking. Itís best to dig plants up with small spade or trowel. The roots should be shaken gently to remove the soil or can be soaked and washed in a pail of water or taken back to the farm and sprayed carefully with a hose to get a better observation of the roots and nodules forming. Its suggested to check and sample 5 different locations of the field for nodule development. Also one should go back and check again just before the flowering stage to insure that the N fertility for the legume will be adequate. Nitrogen fixation ceases with the onset of pod formation in peas and lentils. Good nodulation and N fixation not only benefits the growing crop but also is most beneficial to the crop that will follow in next years rotation. These principles and methods of checking for nodules are also suggested for lentils, chickpeas and soybeans.

 

USEFUL CROP INFORMATION WEB SITES

2005 Variety Performance Information
http://www.ag.ndsu.nodak.edu/aginfo/variety/index.htm

Small Grains Information:
Includes: Hard Red Spring Wheat, Durum Wheat, Winter Wheat, Oats, Rye and Triticale.
http://www.ag.ndsu.nodak.edu/aginfo/smgrains/

2006 ProCrop Agronomic Data Base
http://www.ag.ndsu.edu/procrop/procrop.htm

Row Crops and Oilseeds Information:
Includes: Sunflower, Soybeans, Canola, Flax, Corn and Dry Edible Beans.
http://www.ag.ndsu.nodak.edu/plantsci/rowcrops/main.htm

Crop Production Information - General
http://www.ag.ndsu.nodak.edu/cropprod.htm

2006 Crop Budgets
http://www.ext.nodak.edu/extpubs/ecguides.htm

Weed Control Guide
http://www.ag.ndsu.nodak.edu/weeds/w253/w253w.htm

NDSU Research/Extension Centers Information-
http://www.ag.ndsu.edu/research/recenthp.htm

Northern Crops Institute
http://www.northern-crops.com/

North Dakota Agricultural Statistics Service- USDA
http://www.nass.usda.gov/Statistics_by_State/North_Dakota/index.asp

NDSU Extension Service Biotechnology Information
http://www.ag.ndsu.nodak.edu/biotech/

North Dakota Foundation Seed Program
http://ag.ndsu.nodak.edu/aginfo/seedstock/fss/

NDAWN-NDSU Weather Information site:
http://ndawn.ndsu.nodak.edu/  

Duane Berglund
Extension Agronomist
duane.berglund@ndsu.edu

 

EFFECT OF ENVIRONMENT ON GROWTH, DEVELOPMENT AND YIELD OF SMALL GRAINS

Much of the small grain crop has been planted and based on the latest (May 14th) USDA Crop, Livestock and Weather Report, about a third of the crop has emerged. In areas of the state where planting was not delayed by too much moisture, the weather has been favorable for small grain establishment and early growth. When a crop is well managed the weather during the growing season is usually the major determinant of the type of yield obtained. This can be observed in the huge year to year and location to location variation in yields even when similar varieties and management practices are utilized. In the absence of irrigation, options for managing key environmental variables such as available soil water and air temperature are limited. Small grains are cool season grasses and yield is favored by cool temperatures that prolong developmental phases. For example, a significant amount of the variation in irrigated wheat yields (mean of the HRS wheat variety trial) over the past six years in Carrington can be attributed to the length of the period (the longer the period the cooler the temperature) between the 5-leaf stage and flowering (see following graph). That is one reason that early planting is recommended as it increases the probably that key developmental stages occur during relatively cooler temperatures. Drought can be common in ND and affects plant development by inducing stomatal closure, reducing the rate of photosynthesis and increasing plant temperature which shortens developmental phases. The impact of these stresses on small grain yield and yield components differs depending on when they occur during the growth cycle of the plant. The following describes how temperature and water stress impacts small grain development and yield at key growth stages.

Emergence to Four-Leaf Stage

During the vegetative phase of development, from emergence to about the four-leaf stage, growth is directed towards new leaves and tillers. All leaves that will emerge on the main stem are initiated during this stage. Tillering begins at about the 2-leaf stage but tillers do not become visible until the 3rd to 4th leaf stage. The total number of leaves (typically 8) that will develop is primarily determined by the genetics of the variety and is rarely altered by the environment. The only yield component that is "fixed" at this stage of development is plants ft-2. Yield potential is generally not adversely affected during this phase except by severe moisture stress or very high temperatures.

Four-Leaf to Jointing

At the four-leaf stage, the plant switches from vegetative to reproductive development as the growing point begins forming the spike. Shortly after the six-leaf stage the main stem begins to elongate (begins jointing). Spikelet numbers are fixed in this relatively short period of about 10 days between the four-leaf stage and jointing. Though tiller development can continue beyond this stage, most tillers that produce spikes that contribute to yield will form by the beginning of jointing. Drought stress and elevated temperatures can reduce the number of spikelets that develop and induce tiller mortality. The impact that temperature can have on spike development at this stage was brought home to me during a recent visit to northern Mexico, where enabled by the prolonged cool period from planting to jointing, spikes typically developed more than 20 spikelets.

Jointing to Anthesis

During the period from jointing to anthesis tillers that cannot be supported by the plant die and the number of spikes per plant and the number of florets per spikelet become fixed. Most physiologists seem to agree that yield is most affected by stress during this phase. Any stress that will reduce the rate of photosynthesis (i.e. high temperatures, drought, foliar diseases, competition from weeds) will impact yield potential by reducing the number of tillers that survive and the number of florets that will be fertile. It is in the previous growth stage that most of the potential components of yield are developed but it is during this growth stage the components that will actually contribute to yield are fixed.

Anthesis to Physiological Maturity

After anthesis the number of kernels per plant is fairly well established, though some kernel abortion can occur early in the grain filling process. Any stress that will reduce the rate of photosynthesis can impact the weight of the kernel. High temperature and drought during this stage typically produces kernels with low seed and test weight.

Joel Ransom
Extension Agronomist - Cereal Crops
joel.ransom@ndsu.edu


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