Final Report for LNE98-113
Project Information
The strong increase of markets for local organic milk and bread wheat presents opportunities and challenges to growers. Optimizing the supply of grains and protein supplements to serve either animal ration formulation or human consumption is a basis for this study. There are several dimensions to the issue that have changed dramatically in the three years of this project. The demand for grain throughout the Northeast into Quebec and New Brunswick has grown dramatically. One grain mill in New Brunswick, just over the border of Maine, has reported a onefold increase in demand in just ten years. At the same time supply lines have formed to deliver quality, non-local grains and supplements into the region.
One premise of this study is that economic factors dictate that quality wheat grown in the region will be diverted into human food chain markets from potential animal rations. This is especially the case considering the high value of wheat and other grains that go into regional baked breads. However, working against this trend are quality factors. These may be loosely defined as protein x fungal issues. These factors may act to shift grains back away from human consumption markets and in the time of this study this has become very evident.
There is no simple way to assess the impact of re-directing grain to animal usage based on failure to achieve benchmarks for quality in human consumption. In comparing spring with winter wheats we find less planting and weed pressure for winter varieties, but protein is lower. Fungal spoilage potential is high for wheats harvested later in the summer (spring varieties later than winter), or stored under less-than-optimal conditions (over 65% relative humidity). For small-seeded Vicia faba beans explored as alternative protein sources, satisfactory growth was dependent on a very ample supply of potassium (more than would be needed for grain) and proper inoculation. Botrytis fungi (chocolate spot) was observed only sporadically. Thus study concludes that agronomic and meteorologic factors are likely to be the most significant deterrents for alternative wheat and bean rotations in the Northeast.
Introduction:
There is a rapidly growing market in the Northeast for organic milk and wheat products. Organic milk growth has been at least initially limited by availability of affordable organic grain rations. Therefore it is important to optimize the growing of grains and beans. However, an overriding concern is that, given the dynamics of the organic marketplace, other factors play an important role in determining which organic products may be economically delivered to farms versus human consumption. One example is that organic soybeans will always be sold into human food chains due to the significantly higher value there. Therefore, protein rations could include lower value but suitable crops such as Vicia faba, previously used elsewhere by organic growers, for mixed rations. Furthermore, some mechanism for screening on quality must exist for wheat and other grain products; otherwise, it is very likely that human consumption demand will completely preclude that local grown wheats enter animal markets at all, putting dairy growers back into the same situation.
There is no simple way to assess the impact of redirecting grain to animal usage based on failure to achieve benchmarks for quality in human consumption. In comparing wheats, one guideline is to achieve less weed pressure, yet the tradeoff may be protein that will be lower. This needs to be measured against the markets.
Another obective concerns reducing fungal spoilage, which may be high for wheats harvested later in the summer (spring varieties later than winter) or stored under less-than-optimal conditions (over 65% relative humidity). A goal with regard to alternative proteins sources such as small-seeded Vicia faba beans is satisfactory growth, a sufficient supply of potassium (more than would be needed for grain) and proper inoculation to achieve N-fixation.
Cooperators
Research
During the 1999, 2000, and 2001 growing seasons we evaluated yield, moisture, protein, quality, and mold condition of selected grains and in 2001-2002 we looked at faba beans. We felt we had to do many very basic evaluations since these crops are very unusual in this region. There is very little infrastructure for grain growing, especially as regards access to equipment. For small-scale wheat plots like we employed, selection of suitable technologies to handle harvesting and threshing is problematic. We imported small-scale Japanese ”Cecoco” equipment and travelled to Switzerland to look at small-scale equipment used by the relatively small (<20 ha) organic growers who have managed in some cases quite well. An important need coming out of this project is routine and rapid measurement of grain moisture. A new technique to measure grain moisture by using relative humidity determined with hand-held meters was used. This is compared to the relatively expensive hand-held grain detectors based on conductivity (of moisture) such as sold by John Deere. Elevators purchase very expensive and accurate models of these devices. Another part of this project was the development of a spoilage detection approach by rapid and inexpensive measurement of grain CO2- respiration. Midwest grain scientists who have been working on grain CO2 tests provided insights and assistance. The working hypothesis is to use respiration to determine what is called “remaining storage life.” The remaining storage life determined for wheats harvested in Maine under typical conditions gave values of 150 down to as little as 30 days. A grading system based on harvest/storage moisture and respiration traits would help select wheats for animal ration markets, although animals should be considered as susceptible to mycotoxins. Vomitoxin concentration (a mycotoxin from Fusarium) is frequently used in the trade, yet alone is not enough to safeguard wheat quality. Mustiness alone, the perception of the off-putting flavor of it, is a deterrent in grain sales, and all growers and purchasers we worked with routinely sniff their grains. Wheat moisture equilibration constants show that at atmospheric RH above 65%, significant moisture related mold problems may ensue in harvest and storage.
We experimented with the small seed field bean (Vicia faba) based on earlier reports from Nova Scotia and Europe about viability of this cultivar for alternate protein (Patriquin, 1981; Vogtman et al, 1978). Faba bean production was evaluated in 2 field trials using 7 different varieties of faba bean: Ackerperle, Minnesota Horse Bean, Diana, Aladin, Petit Tick, Outlook, and Hertz Freya. We compared to soybeans as a standard control protein. A second trial evaluated effects of potassium fertilization and inoculation.
In our Maine trials, faba beans grew faster than soybean until mid-summer, partly because they favor cooler conditions. They produce copious, upright biomass with total plant yield (in green manure terms) ranging from 5-9 tons/acre. At harvest, faba beans had greater stover (stem/leaves) residue than did soybeans (approximately 1.5 t/a as versus 1.1 t/a for soybeans). Needless to say, to be used in an animal rations, faba beans no not have to be heat-treated. Faba seed protein however is significantly lower than soy (33% vs. soy of 40%).
Ackerperle consistently outyielded the other faba bean varieties. The lowest yielding were with Diana and Petit Tick. However, under favorable circumstances, yields did not exceed 20-25 bu/acre. Yield were significantly affected by soil pH, inoculation, and supply of potassium. Application rates of 100 lb/a K supplied via Sul-Po-Mag increased yield more with faba beans than soybeans, and with potassium, our faba beans (Ackerperle) closely compared to soybean yield.
Inoculuation with suitable sub-strains of Rhizobium leguminosarum must be carefully practiced since faba requires a differnt incoculaum than that normally found in seed supply stores. Inoculation increased yield in all our plots by an average of 160%.
A field experiment was established in Mt Vernon, Maine to test a variety of grain and bean scenarios. The soil test across the site at five locations is given in the table above. A light topdressing of 7 t/acre finished compost was applied to the field estimated to provide 10 lb/a available N after fall tillage. The respiration rate and pH along with moderate-high organic content suggested this soil would release about 36-44 lb N/a per year. Thus, with a light application of compost (or previous plowdown of a legume/hay) the nutrient-nitrogen requirement of our crop is met.
We evaluated spring and winter grown wheats. All winter wheats were varieties selected from organic growing in Switzerland, provided to us by wheat breeder Dr. Peter Kunz. These were Pollux, Atar, Asita, Alkor and Sirius. As far as we could determine, these varieties would be available through an international seed house in Germany. Seeding rate in experimental plots of 1000sq.ft. each were 126 lbs/acre broadcast and lightly disced and rolled.
All varieties germinated well in early fall sowing of September 26 and developed good to excellent stands. The variable density can be seen the following summer. We lightly disced the plots in the spring after tillering which is a practice used by european organic growers to reduce wheat growth. Tillering was an important aspect of growth and weed suppression. Modern varieties not necessarily suited to organic production are those that tiller very little, and typically organic growers selected for plants with excellent tillering. We had low to high tillering and the best yield quality was seen in the case of the Asita variety with high density and heavy tillering.
Plant height plays an important role in grain quality, in that the higher plants are less susceptible to fungal pressure and may better out compete weeds. Modern varieties for conventional farming may be moderately dwarfed and therefore presume significant weed control. Our varieties ranged in height from 72 to 103 cm, which is excellent. This compares to a variety of wheat trials in the maritime province showing 70 to 101 cm prior to harvest (Scott, 1998). Average wheat heights for Iowa winter wheats is about 28- 34” (71 - 86cm). It is a tradition in European organic wheat practice (especially with biodyanmic growers) to select for the tallest grain varieties, some wheats exceeding 120cm.
Our yields were on the average to below average scale judging from other trials in the Northeast. This is most likely due to some stands loss from light discing for weed control. In many trials, weeds create such pressure in organic wheat plots that the subsequent crops are compromised. The use of winter wheats which results in good stand development where annual weeds winter kill prior to spring growth is one strategy. The bushel test weights were respectable. Iowa winter wheat test weights in 2002 ranged from about 55-58 lbs. At 60#/bushel weights the yield range for our winter wheats was only from about 16 to 30 bu/a, or about half that reported for western winter wheat.
All the wheats above produced good test loaves in baking trials. However, the local mill purchasing wheats for baking has established a 13.5% margin for protein, with some allowance down to 12% (personal communication, R Libby).
Wheats that do not meet a threshold for protein (or mold count--see later discussion) may be sent to animal production. However, an animal feed mill would ideally be present in the same region. This continues to be an issue in Maine for organic production, where most the ration for dairying is now provided by corn/soybean blends from outside the region.
Nitrogen removal in grains for the yield and nitrogen content as above described will be only 22 to 38 lb/a. Straw will yield approximately 1.5-2x the amount of grain depending on stem length and with less than half the N content (or about 0.9%) the potential N-removal per acre would be about an additional 20 lb/a. Thus, for our samples the total grain + straw N-budget/acre assuming removal of all residues with the grain is 38 to 65 lb/a N. This is to be assumed to be on the low side since our yield with better management could be higher.
We did not perform extensive economic assessments for the given set of yield data. However, we estimate variable costs to be up to $90/acre, including compost, seeds, supplemental fertilizers and mechanical weeding. At $0.12/lb price for organic bread wheat, and at our given yields, the return over variable costs is likely to be on average around $100/acre, and would only reach $300/acre at a yield of 55 bu/acre.
Several other trials of wheat (spring) and other farmer trials were assessed in this project. In the first spring, we planted 4 varieties of spring wheat recommended out of New Brunswick mills. These included Bellvedere, Walton, Pollet and Grandin. The plants were visually scored during the season and yields estimated from small plots and protein determined.
In conducting these studies, we found moisture to be an evident issue. We also performed extensive respiration trials to assess the moisture conditions on or just after harvest. Several of the grains clearly had moisture properties at and above the threshold of safe levels (<=14%). In some cases, in mid-western wheat growing, wheat over 14% will not be purchased. Yield of the Woods End varieties ranged from 0.8 to 1.1 ton/ac (38-50 bu/ac) with Grandin outperforming several others. This is a popular variety in New Brunswick organic production, having originated in North Dakota. Grandin also achieved the highest protein of the tested varieties, and Woods End Grandin was higher than all other farms tested and also slightly higher than New Brunswick trials previously reported Grandin highest protein 15.9% (Jennifer Hart, personal communication). Grandin, however, is not as tall a wheat as Walton is, which also did well. Gunner had the tallest aspect in trials at other sites, good for outgrowing weeds, but was a much later maturer, putting it at the end of the acceptable moisture spectrum.
Project Outcomes
Impacts of Results/Outcomes
The foregoing studies by Woods End and evaluation of grains from other farms have shown that both winter and spring wheats can be grown successfully but with varying constraints. A significant aspect that has emerged is that spoilage may be a primary driver in how grains are used.
Optimal time of sowing, whether winter or spring, are influenced by soil type and local climatology and also by the amount of expected weed pressure. Nutrient management will influence yield and in turn the nitrogen (=protein) content of the grains which may significantly affect choices for end use. Presently, in Maine, a system has evolved where the possibility exists that a significant but variable amount of lesser-grade wheat (by milling-baking standards) could be diverted to animal management.
Possibly a more scientific approach in quality management could be made by applying the concept of “days remaining in storage” (Stroshine, Purdue University), based on careful assessment of likelihood of spoilage at time of harvest and first storage. This approach uses grain qualities, primarily respiration to determine the nearness--or distance to--the threshold where time becomes of the essence for disposal of a grain product. Failing that, time-to milling-baking markets, on-farm use for forage/grain mixes would be most appropriate.
Woods End Research Laboratory has previously developed a gel technology for detecting carbon-dioxide gasses under field conditions which is currently used to accurately measure the rate of carbon-dioxide (CO2) evolution in samples of soil (USDA, 1998). For composts the test is important to indicate when the product is finished since active composts may harm soils and plants. Used for soils, the “Solvita” test enables ecologists and farmers to estimate carbon turnover rate, an important indicator of soil fertility (Doran et al., 1998).
Based on literature review, we determined that respiration assessment of grains is a viable concept to represent potential and actuality of spoilage. Therefore, we have used these CO2 soil kits to assess storability of grain products.
This innovation is proposed to fill the gap that exists with regard to rapid detection technology for assessing spoilage conditions in grains such as corn and wheat (Stroshine, 1995). The chief characteristic of spoilage of grain is the after-harvest growth of fungi in dependence on moisture. This mold growth may be barely visible but is accompanied by production of tell-tale amounts of CO2. Our goal, therefore, is to adapt the existing respiration approach to easily and effectively detect this carbon dioxide respiration. This work is accomplished by surveying conditions in harvested grains at moisture contents typical of commercial storage. The objective is that Solvita tests may be routinely performed on samples to predict both previous damage as well as storability defined as the amount of time grain may remain in storage without dangerous spoilage.
Collaborating throughout this project has been Dr. Richard Stroshine in the department of Agricultural and Biological Engineering at Purdue University. Dr. Stroshine, a national expert on grain spoilage, is conducting parallel studies using corn samples in which the moisture is artificially augmented to induce obvious degradation. Purdue has provided Wood End test samples of the same grain batches. Incorporated into this report are selected data from Dr. Stroshine’s key trials to date (Stroshine, 2000).
In order that a field-test CO2 rate test may be commercially useful, the test result at any moisture content should accurately and reliably reflect the degree of degradation of the sample, regardless of any recent changes in moisture content (MC), either by the owner or in the testing laboratory. With this in mind we have conducted CO2 tests on several grain types, at MCs both as-received and adjusted to standardized levels of 13-22%, and compared these results to laboratory Solvita tests conducted by Stroshine. In addition, in order to provide independent corroboration of fungal contamination, analyses for ergosterol content have been carried out on the same samples. Finally, we have included estimates of grain condition, based on known details of the harvest condition and storage history of each particular sample.
Our major findings include the following:
Tests on fresh grains showed Solvita results sharply increasing in the range of MC corresponding to spoilage threshold conditions of equilibrium relative humidity (ERH) of 75-85%.
Freshly harvested wheat gave Solvita results indicating CO2 rates proportional to MC and increasing about 5-fold in the range of 14-16.5% MC.
Wheat and corn stored for one to three years had Solvita results proportional to MC at the time of testing, and increasing about fivefold in the range of 13-16% MC.
Wheat and corn stored for one to three years and tested at adjusted moisture of 14 and 15% had Solvita results that corresponded to the known history in storage.
Estimates of condition (based on known details of storage history) of 12 corn samples correlates very strongly and highly significantly with Solvita results performed as-received and at adjusted MC of 14 and 15%.
The independent fungal contamination test for ergosterol content showed good correlation with Solvita results on as-is and moisture adjusted grain. Ergosterol is a fungal cell-wall component which we used in the study to ultimately determine presence of fungi on grains.
The impact from these studies is likely to be twofold.
1) The results of these trials may act to bolster confidence in winter wheats. Winter varieties of wheat, though lower in protein, may help organic growers significantly with regard to annual weed control and wet-soil planting conditions encountered with spring wheats.
2) A grading system for wheat may be devised based on test traits and level of partial spoilage or storage history.
Economic Analysis
We did not perform extensive economic assessments for the given set of yield data. However, we estimate variable costs to be up to $90/acre, including compost, seeds, supplemental fertilizers and mechanical weeding. At $0.12/lb price for organic bread wheat, and at our given yields, the return over variable costs is likely to be on average around $100/acre, and would only reach $300/acre at a yield of 55 bu/acre.
Farmer Adoption
We were generally pleased with the ability to grow small-seeded faba beans which can compete well with soybean on an agronomic scale, and prefer a cooler season as we have in Maine. Faba beans have been described in the alternative farming literature for over a decade and have not taken off. They require a very sufficient supply of moisture and especially potassium and must be properly inoculated with an alternative vetch-type inoculum. With 25% less protein than soy beans, their value in the rotation and relative cost must be carefully weighed.
In the time of this study, between 1998-2002, the situation of feed-grain supply into Maine for organic production has changed dramatically. Growers who attempted to grow grains have found now a ready supply via a Canadian miller. Other growers found weed pressure from wheats and fungal conditions at or around the time of harvest to represent very grave risks. However, growers who place a high value on development of self-sustained systems, fitting the central philosophy of organic farming, also remain very interested in testing grain/bean rotations that may serve their needs and provide some market flexibility. It is hoped that this study will contribute to the continued exploration.
Areas needing additional study
Our studies indicate that, for wheat production, moisture management in pre-harvest and post-harvest times will be a major factor of acceptability of this crop in the marketplace; it will also partly or largely determine if the crop will be used in lower-value animal rations. Because the latter event may appear accidental rather than planned, it is difficult to lay out a strategy. By using our respiration approach to predict post-harvest spoilage potential, growers can select for grains that need to be marketed immediately vs. those that will store well. If immediate markets do not exist for high-spoilage potential grains, then animal rations should be considered. In many cases, millers prefer to work with growers who possess suitable on-farm storage. Thus any spoilage potential may be an absolute bar to use in high value milling-baking markets.