Protein crops grown locally without chemicals would reduce the cost of producing organic milk and meat. Protein crops would also provide an alternative to farmers seeking replacements for traditional crops and production methods. This project evaluated the yields and cultural requirements of organically grown winter field peas and soybeans. Plots were grown with and without irrigation, yields recorded, nutrient content measured, and economic potential determined. Field scale crop production and animal feeding trials followed in 2006-07. This crops can benefit organic crop rotations and be fed economically to animals.
Develop alternative crops, especially those high in protein, which can be grown organically by local farmers and used in the region by local animal producers. A subsequent feeding trial evaluated:
1. acceptability of minimal processed field peas and Oregon soybeans to dairy cattle, and
2. milk production and intake of a total mixed ration (TMR) when these proteins replaced the entire conventional protein supplement.
A high protein crop suitable for production locally without chemicals would reduce the cost of producing organic milk and livestock. It would reduce the import of nutrients from the Midwest to the West. Crops for use as protein supplements would provide an alternative to farmers seeking replacement crops for traditional crops and production methods.
Growing Trials. The soybean trial was conducted on an silt loam soil (pH of 7.5, 1.9 percent organic matter) previously planted to wheat. The field was disked twice, moldboard plowed, ground hogged twice, and bedded to 30-inch rows in the spring of 2005.
Three Oregon State University soybean lines were planted in plots 4 beds wide by 25 ft long. The plots were arranged in a randomized complete block design with six replicates. The seed was planted on June 2 at 200,000 seeds/acre in 3 rows on each 30-inch bed using a plot drill with disk openers. The rows were spaced 7 inches apart (Fig. 1). Rhizobium japonicum soil implant inoculant was applied in the seed furrow at planting along with the seed. Emergence started on June 10. The trial was irrigated with a mini-sprinkler system (R10 Turbo Rotator, Nelson Irrigation Corp., Walla Walla, WA). Risers were spaced 25 ft apart along the flexible polyethylene hose laterals that were spaced 30 ft apart and the water application rate was 0.10 in/hr.
The field was irrigated when the soil water tension at 8-inch depth reached 50 centibars (cb). Soil water tension was monitored by six granular matrix sensors (GMS, Watermark Soil Moisture Sensors Model 200SS, Irrometer Co., Riverside, CA) installed in the bed center at 8-inch depth. Sensors were automatically read three times a day with an AM-400 meter (Mike Hansen Co., East Wenatchee, WA). The last irrigation was on September 10.
The field was hand weeded on July 8 and on July 19. The field was sprayed with Aza-Direct® (azadirachtin) at 0.025 lb ai/ac and Success® (spinosad) at 0.19 lb ai/ac on July 21, July 29, August 3, August 17, and August 26 for control of lygus bugs, stinkbugs, and spider mites. Aza-Direct® and Success® are approved for organic crop production according to the Organic Materials Review Institute (O.M.R.I., Eugene, OR).
The middle two beds in each four-bed plot were harvested on October 10 using a Wintersteiger Nurserymaster® small plot combine. Beans were cleaned, weighed, and a sub-sample was oven dried to determine moisture content. Samples of each cultivar were sent to Oregon State University for analysis of crude fat and crude protein. Crude fat was analyzed using ether extraction and crude protein was analyzed using a copper catalyst Kjeldahl method. Moisture at the time of analysis was determined by oven drying at 100°C for 24 hours. Dry bean yields; crude fat, and crude protein were corrected to 13 percent moisture. Variety yield and seed counts were compared by analysis of variance. Means separation was determined by the protected least significant difference test.
In late October, 2005, varieties of winter field peas were planted in dryland plots at the Columbia Basin Ag Research Center near Pendleton, OR. The plots were conventional tilled to incorporate a summer cover crop and no herbicide was used.
Based on the yield and composition data, the soybean variety ‘M12’ and field pea variety ‘Universal” were grown in acre plots in 2006 and 2007 for an animal feeding trial later in 2007. A request for a no-cost extension to the proposed timeline was approved.
Feeding trial. Twenty-one Holstein cows in early lactation were assigned at random to one of three diets based on current milk production, dry matter intake, and familiarity with the individual Calan® feeding gates. Cows were fitted with electronic transponders that allowed them into one and only one feeding station. They were fed a standard total mixed ration (TMR) in the individual gates for 3 days prior to starting the trial. One group of seven cows continued on the regular TMR for the next 10 days (days 4 through 14). This group is noted as SOYDIST. The other two 7-cow groups received a TMR equivalent to the herd TMR, but without the soybean/distillers grain. Either extruded soybeans (SOY) or extruded filed peas (PEAS) were hand mixed into each cow’s TMR immediately before the morning feeding. The three diets were isonitrogenous and isocaloric. Cows were fed approximately 75 pounds of the TMR with added protein supplements in the morning and 50 pounds without added supplement in the mid-afternoon. Daily refusals were weighed and discarded. Total intakes, number of meals, size and length of meals, and eating rate were measured using scales under the feed bins and data collection computer software. Milk production was recorded for each milking for 15 days before, throughout the 3-10 day feeding periods, and 15 days after supplement feeding using electronic flow meters and data collection software.
At 14 days, each seven-cow group was rotated to the next alternate ration. This was done again at 24 days so each cow received 10 days of each diet over the 30 day trial. Diets are shown in Table 4 and nutrient composition of soybeans and field peas is shown in Table 5. Ingredients and nutrient composition of the commercial pellet fed to all cows is in Table 6. Milk yield and cow DMI was measured daily. Average body condition score was estimated on Day 14, and Day 34.
Irrigated soybean yields in 2005 ranged from 55.7 bu/ac for ‘M9’ to 57.2 bu/ac for ‘M12’ (Table 1).
Yields in this trial were substantially lower than for the same cultivars in a trial under conventional production practices in another field at MES. Yield differences between the conventional and organic systems may be explained by differences in irrigation systems, soil types, and planting dates. The conventional system was furrow irrigated. Lack of experience in irrigating soybeans with the mini-sprinkler system resulted in a drier average soil water tension for the organic system (34.4 cb) than the conventional furrow irrigation system (28.2 cb). The field used for the organic system had soil with a history of lower productivity than soil used in the conventional production system. The later planting date of the organic soybeans resulted in emergence 10 days later than the conventional soybeans, so the soybeans developed during a later and less favorable time of year. The conventional soybeans reached maturity on September 6 and the organic soybeans reached maturity on September 16. In spite of these differences, it is clearly feasible to produce organic soybeans at Ontario, Oregon.
Grain yields of the winter pea varieties ranged from 1900 to 3000 lb/ac. Spring peas produced about 700 to 1100 lb/ac at Pendleton and 300 to 600 lb/ac at Moro. Winter pea lines yield 1200 to 1900 lb/ac more than spring types. The variety ‘Universal’ appears to yield well under both dry and wet years but the yield was not significantly different from Badminton and Mozart under dry and wet conditions. We, therefore, will recommend all three varieties to growers.
Dry matter intake did not differ by protein source. Likewise, general body weight and estimated body condition scores were similar for cows on all rations throughout the trial. It was evident that cows lost some weight through the trial due to the heavy milk production. This is common in early lactation animals. Dry matter intake would not be expected to differ due to similar nutrient concentrations of the diets and similar body weight and production level of the cows. There was a tendency for lower intake in the second feeding period (d15-d25) for all cows. However, daily intake variations were greater and weighing error was partly to blame.
Total intake as-fed and on a dry matter basis were excellent for all three diets. Values for each are shown in Table 2 and compared to values for mid-lactation Holsteins recorded in a previous trial. Each group tended to drop about 20 pounds as-fed intake the day they were first switched to a new diet. Intake recovered to pre-supplemented levels by the third day of the feeding period. Several cows ate for shorter times and had smaller meals during this intake depression while the others ate as often and as long but at a slower rate of consumption. It is common for cattle to experience an adjustment when feed sources change. Having the protein supplement in a mechanically mixed ration would likely overcome this minor problem.
Milk yield did not differ by protein source. Average milk production was just over 50 pounds per day across all groups. Milk production and dry matter intake are summarized in Table 3.
Soybeans and winter peas are a potentially valuable new crop for Oregon. Soybean could provide a high quality protein for animal nutrition and oil for human consumption, both of which are in short supply in the Pacific Northwest. In addition, edible or vegetable soybean production could provide a raw material for specialized food products. Soybean is a valuable rotation crop because of the soil-improving qualities of its residues and its nitrogen (N2) -fixing capability. Because of the high-value irrigated crops typically grown in the Snake River Valley, soybeans may be economically feasible only at high yields. Locally grown proteins could cut the cost of protein for organic livestock production by half while giving local organic growers a reasonable value crop for rotation on irrigated and non-irrigated land.
Peas can be grown in a mixture with barley, oat, triticale or wheat. Peas are an excellent N fixing crop (30lb/ac/yr from vine residue) and have great potential as a green manure crop instead of fallow. Peas can return more than 80 lb N/ac to soil if tilled in mid-season. The response of pea to moisture is similar to wheat.
Educational & Outreach Activities
Feibert, E.B.G., C.C. Shock, and L.D. Saunders. 2006. Soybean Performance in Ontario in 2005. Oregon State University. Malheur Experiment Station Special Report 1070: 201-206
Feibert, E.B.G., C.C. Shock, and L.D. Saunders. 2006. Organic Soybean Production in Ontario in 2005. Oregon State University, Malheur Experiment Station Special Report 1070: 207-209
Machado, S. and B. Tuck. 2006. Alternative Rotation Crops in 2005 Dryland Agriculture Research Report, Oregon State University. Columbia Basin Ag. Research Center. OSUES Special Report SR1061.
An update on yields and quality of the protein sources was presented to the Western Organic Dairy Producers Alliance members in October, 2007. There were about 60 producers and dairy suppliers in attendance. This summary of research will be adapted to posting on the developmental eOrganic website sponsored by eXtension.
Price ranges from $5.50 to >$11.00/cwt for conventional winter field peas result in potential gross returns of $82.50 to $165.00/1500 lb/ac. Organic prices are about twice as much. With today’s higher price for wheat, it is the most profitable dryland crop. With soybeans at the current farm price of $8.35 a bushel, income would be $459 per acre with a 55 bushel yield. Today’s prices for feed grade organic beans are $17.00 in Seattle and $16.50 in San Francisco. Again, the gross returns will be about twice as much for organic production corrected by any difference in yield.
There has been no adoption yet. The study has just been completed and conventional crops are at all-time high prices. Growers are not considering alternative crops at this time.
Areas needing additional study
There is room to improve yields of organically grown protein sources. Irrigation and manure timing can be improved. Combination of a winter-grown forage crop with the spring-planted proteins could increase feed production while maintaining soil organic matter. Weed control will continue to be a challenge. Development of organically-acceptable natural allelopathic chemicals could be helpful.