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Information for Buckwheat Growers

Northeast Buckwheat Growers Newsletter

No. 24 September 2007
Edited by Thomas Bjorkman, Cornell NYSAES, Geneva NY

Field Day on August 28, 2007
The thirteenth annual Northeast Buckwheat Field Day was held August 28 at the New York State Agricultural Experiment Station research farm. A lively group of farmers attended, having excellent discussions about water management, field preparation, fertilizer, harvesting, and health benefits of buckwheat. One group stayed after the field day to learn more about Dr. Curt Petzoldt's use of buckwheat in integrated pest management.

There were several field demonstrations. One showed the effect of varying the seeding date. Planting early results in uneven fruit set and ripening. A May 15 seeding had few ripe seeds and many immature ones at 105 days. The very oldest seeds were falling off. Maturation was more promising in middle to late June. The standard early July planting was just filling, so it could not be evaluated. The soil on May 15 was too cool for rapid and even emergence, so this planting suffered from gaps that had filled with lambsquarters. Stand establishment was faster the later it was planted. August was best, although that is too late for a seed crop.

A demonstration of field preparation for double cropping showed that no-till into vegetable residue failed for the third year in a row. The soil was too hard. However, incorporation of crop residue and a short wait for decomposition (a week or less) gave an excellent buckwheat stand. This no-till demonstration was a good contrast to photos that Terry Bistrovich provided of his no-till farm, where the buckwheat stand using his Haybuster drill was uniform and vigorous. Good no-till doesn't happen at once, but when it is in place, the results can be excellent.

Production notes: harvest ideas
There is no way to know how soon to harvest by looking at a field from the road. The plant often has many green leaves, and sometimes even flowers, when it is ripe for harvest. Leaf drop is associated with temperature, nitrogen, water, and daylength, but it is not associated with seed ripening. The only way to know is to hold clusters of seeds in your hand.

Check ripeness by pulling all the full seeds off several plants. Individual plants are often quite different from each other, and the top and middle of the plant have different maturity. Usually, the most mature clusters are about 1/4 of the way from the top.

For windrowing, filled seed that is turning from green to brown will mature in the swath. More mature seed will be held in the swath.

For direct cutting, the goal is to let the seeds mature as much as they can, but to harvest before they fall off. Unfortunately, that happens quickly, especially after a frost. Starting about September 20, check the heads every few days. If you can easily pull the seeds off with your hand, it is ready to harvest. If you can shake them off the plant, they are too mature and you need to harvest immediately. When seeds come off too easily, the combine will scatter them across the field. Be aware that the seeds come off more easily in the afternoon, when the peduncles have dried a bit. Correct for that effect when sampling, and use it to adjust for the maturity by choosing the time of day to harvest.

Windrowing. Broadcasting seed can be useful for supporting the windrow because it will not fall between rows. In drilled fields, the windrow can be held up better if it is harvested at an angle to the drilled rows. This is particularly useful if the plants are short, as they were in dry areas this year.

Windrowing without dedicated equipment. At an earlier field day, growers described how they modified a haybine for windrowing. It involved opening it up completely with wood blocks to avoid crimping the stems and beating the seeds off the plants. The swath should be held high enough that there is good air circulation underneath. If wind and rain push it to the ground, seeds will sprout, the leaves will rot, and the combine won't be able to pick it up.

For picking up the windrows, a standard small grain head can be used if the windrows are high enough. The reel is kept in the disengaged upper position. The head runs a few inches below the bottom of the windrow. The drawback is that stems are recut, and the small stem pieces are hard to separate from the grain in the combine. Since the stems have high moisture, the load needs to be cleaned quickly so that it does not heat up. A local seed or grain cleaner, or the mill receiving the grain can do that separation.

Combine settings. The reel speed is more important than with buckwheat than with many other crops. Because the more mature seeds come off easily, the reel speed needs to be matched precisely to the ground speed. The plant should be cut high without shaking, and laid gently on the table. The cylinder speed recommended by combine manufacturers is low. In part, that is because it does not take much action to remove the seeds, but it also prevents splitting of the hull and bruising the seed.

Research news
If buckwheat plants are stunted by drought before flowering, they never really recover to produce a good yield. The reason is found in a new publication from the buckwheat research team in Leuvain, Belgium. Valerie Cawoy and her coworkers traced the development of young plants to see what the fate of the flowers was when water shortages were imposed at different times. Even though flowers first open about 30 days after sowing, the main-stem flower clusters are all developed between 14 and 21 days after sowing. This is about when the first true leaf is fully expanded. These clusters are responsible for most of the yield of buckwheat raised in the Northeast. Water stress during this period reduces the number of flowers in each early cluster. It also reduces the amount of pollen, which is already in borderline supply.

In a dry year like 2007, it was helpful to conserve soil moisture. If the soil is friable enough for buckwheat roots to grow, by 2 weeks they are down into the moist soil and supply the small plants with enough water.

  • Cawoy, V., S. Lutts, J-F. Ledent and J-M Kinet. 2007. Resource availability regulates reproductive meristem activity, development of reproductive structures and seed set in buckwheat (Fagopyrum esculentum) Physiologia Plantarum 131:341-353.

Conserving soil moisture
In many parts of the region, soils were rather dry by the time buckwheat was ready to plant. Dry soil causes uneven emergence and early water stress can hurt seed production even if rain returns, as described in the research news above.

How does one conserve moisture for better buckwheat establishment? It is helpful in any year to till the ground 3-4 weeks before sowing buckwheat. Tillage that early reduces the amount of water loss compared to tilling at the end of June. It also breaks the capillary movement of deep water to the surface where it can evaporate. Rolling the surface lightly can reduce moisture loss, but if it is rolled heavily, the soil will compress enough that the moisture wicks out again.

Harrowing a couple times in the weeks before sowing is often useful for soil condition and weed control, but it also dries the soil considerably. If you are trying to conserve soil moisture, keep any harrowing extremely shallow.

At planting, a risk decision has to be made. If the surface soil is too dry for germination, a deep harrowing can bring moist soil up to aid germination, but can spell disaster if significant rain does not come in a week or two.

After planting, it helps to compress the surface of the soil enough to reduce drying "ventilation" around the seeds, to encourage capillary movement of moisture from nearby, and to increase the amount of moisture-carrying soil that is in contact with the the seed. Nate Herrendeen of CCE Niagara County has seen packing after drilling make soil moisture more uniform through the field and make the stand impressively even.

In dry years, buckwheat growers on the heaviest soils often do very well because the high water-holding capacity can pull the crop through long dry spells. Dry years are also when established no-till growers reallys see a big benefit.

Health and buckwheat
Celiac. People with celiac disease can't eat any grains because they contain gluten. Buckwheat is naturally gluten-free, but not all buckwheat products are gluten-free. This fact has put buckwheat on the questionable list in some celiac guides. An influential new list definitely has buckwheat in the approved and safe foods category. Birkett Mills and Bob's Red Mill are producers highlighted for having dedicated processing facilities as well as testing for gluten. Northern Quinoa Corp. is noted for having dedicated equipment.

  • Raymond, N, J. Heap, S. Case. 2006. The gluten-free diet: an update for health professionals. Practical Gastroenterology. Sept. 2006. p. 67-92.

Allergy-free dough. In contrast to celiac, some people are allergic to a protein in buckwheat, so they can't eat buckwheat. A group at Osaka Prefectural University has found a way to remove that protein so that even allergic people can get its other health-promoting benefits. The team fermented buckwheat groats with the same microbe used to turn soybeans into tempeh. They found that the problem protein broke down in less than a day. The texture of the dough made from the fermented buckwheat was a lot softer, and didn't make a satisfactory noodle by itself. They are working on ways to make products with this new hypoallergenic and healthy buckwheat with tempeh.

  • Urisu, T. Adachi and N. Morita. 2006. Hypoallergenic buckwheat production by Rhizopus oligosporus and its application to soba noodle. Food Research International 39: 598-605. doi:10.1016/j.foodres.2005.12.003.

Cancer chemotherapy. The hunt for natural anticancer compounds has come to buckwheat. Some plant phenolics are expected to have the property of inhibiting cancer cell growth a lot more than healthy cells. Buckwheat hulls are high in phenolics, so one research team made various phenolic extracts of buckwheat hulls and tested them against a number of different cancer cells. Several extracts appeared to inhibit cancer cell growth by 80% but healthy cells by only 30%. They intend to further purify and identify the active compounds, expecting that they may able to produce a chemotherapeutic material at very low cost.

  • Kim, S.H., C-B Cui, I-J Kang, S.Y. Kim, S-S. Ham. 2007. Cytotoxic Effect of Buckwheat (Fagopyrum esculentum Moench) Hull Against Cancer Cells. Journal of Medicinal Food 10: 232-238.


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