Malheur Experiment Station Information for Sustainable Agriculture

SOYBEAN PERFORMANCE IN ONTARIO IN 2007

Clinton C. Shock, Erik B.G. Feibert, and Lamont D. Saunders

Malheur Experiment Station

Oregon State University

Ontario, OR

Introduction

Soybean is a potentially valuable new crop for the Pacific Northwest. Soybean can provide raw materials for biodiesel, high quality protein for animal nutrition, and oil for human consumption, all of which are in short supply in the Pacific Northwest. In addition, edible or vegetable soybean production can provide a raw material for specialized food products. Soybean is valuable as a rotation crop because of the soil-improving qualities of its residues and its nitrogen (N₂)-fixing capability. Because high-value irrigated crops are typically grown in the Snake River Valley, soybeans may be economically feasible only at high yields. The most common rotation crop in the Treasure Valley is irrigated winter wheat, so soybeans need to be competitive with winter wheat. Through breeding, selection, and the development of appropriate cultural practices, we have succeeded in achieving high yields.

Soybean varieties developed for the midwestern and southern states are not necessarily well adapted to Oregon's lower night temperatures, lower relative humidity, and other climatic differences. Previous research at Ontario, Oregon has shown that, compared to the commercial cultivars bred for the Midwest, plants for eastern Oregon need to have high tolerance to seed shatter, reduced plant height and lodging, increased seed set, and higher harvest index (ratio of seed to the whole plant).

M. Seddigh and G.D. Jolliff at Oregon State University, Corvallis, identified a soybean line that would fill pods when subjected to cool night temperatures. This line was crossed at Corvallis with productive lines to produce 'OR 6' and 'OR 8', among others. At this point, the development moved to Ontario, Oregon. The latter two lines were crossed at our request for several years with early maturing high-yielding semi-dwarf lines by R.L. Cooper (USDA, Agriculture Research Service, Wooster, OH) to produce semi-dwarf lines with potential adaptation to the Pacific Northwest. Selection criteria for F₂ and subsequent lines at the Malheur Experiment Station (MES) included high yield, zero lodging, zero shatter, low plant height, and maturity in the available growing season. We specifically chose seed lines with clear hilum so that off colors would not contaminate possible food products with off colors. Also, we selected for light seed coat and seed color to allow the widest possible food product manufacture.

In 1992, 241 single plants were selected from 5 F₅ lines that were originally bred and selected for adaptation to eastern Oregon. Seed from these selections was planted and evaluated in 1993; 18 F₆ selections were found promising and selected for further testing in larger plots from 1994 through 1999. Through these years of breeding and selection we successfully reduced plant height, reduced plant lodging, and increased yields. Of the 18 lines, 8 were selected for further testing.

In 1999, selections from one of the advanced MES lines were made by P. Sexton at the Central Oregon Agricultural Research and Extension Center (COAREC) in Madras, Oregon to help maintain germplasm true to type. Sixteen of these selections made in Madras were chosen for further testing. In 2000, we made further selections from six of our 1992 MES lines and from OR-6 to help maintain germplasm true to type.

Starting in 2005, a new planting configuration was used. The old planting configuration had one plant row on a 22-inch bed. The new planting configuration has 3 rows on a 30-inch bed. Our objective is to provide a more uniform distribution of the plants over the soil surface. The more uniform plant distribution resulted in higher yields, perhaps due to improved access to light, nutrients, and water for individual plants. The new planting configuration retains the same seeding rate of 200,000 seeds/acre as the old configuration.

This report summarizes work done in 2007 as part of our continuing breeding and selection program to adapt soybeans to eastern Oregon and includes the added yield enhancements achieved by changing the planting configuration. Our soybean reports from the last decade are available at our station web site <http://www.cropinfo.net>. There is a search function on the home page that will conveniently find all of our recent reports dealing with soybeans by using the key word "soybean".

Materials and Methods

The 2007 trial was conducted on an Owyhee silt loam (pH of 8.0 and 1.2 percent organic matter) previously planted to wheat. One hundred and seventy-two pounds of phosphate (P₂O₅), 100 lb sulfur (S), 5 lb iron (Fe), 5 lb manganese (Mn), 2 lb copper (Cu), and 1 lb of boron (B) were broadcast in the fall of 2006. After fertilization, the field was disked twice, moldboard plowed, groundhogged twice, and bedded to 30-inch rows. On May 15, 2007, Micro-Tech^® herbicide was applied at 3 lb ai/acre and the field was harrowed to incorporate it.

Five commercial cultivars, 5 older lines selected at MES in 1992, and 29 lines selected in 1999 and 2000 were evaluated; these 39 selections were arranged in 10-ft by 25-ft plots in a randomized complete block design with four replicates. The seed was planted on May 16 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). Bradyrhizobiumjaponicum inoculant (Cell-Tech^®, EMD Crop BioScience, Brookfield, WI) was applied to the seed before planting. Emergence started on May 21.

The field was furrow irrigated when the soil water tension at 8-inch depth reached 50-60 centibars (cb). To understand how to irrigate using soil water tension as an irrigation criteria, see our extension brochure (Shock et al. 2005) listed below. 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).

For lygus bug, stinkbug, and spider mite control, the field was sprayed with Lannate^® at 0.9 lb ai/acre on July 15,dimethoate at 0.5 lb ai/acre on August 3, and Comite^® at 2 lb ai/acre on August 10.

Plant height and reproductive stage were measured weekly for each cultivar. Prior to harvest, each plot was evaluated for lodging and seed shatter. Lodging was rated as the degree to which the plants were leaning over (0 = vertical, 10 = prostrate). The middle two beds in each four-bed plot were harvested on October 16 using a Wintersteiger Nurserymaster small plot combine. Beans were cleaned, weighed, and a subsample was oven dried to determine moisture content. Moisture at the time of analysis was determined by oven drying at 100°C for 24 hours. Dry bean yields were corrected to 13 percent moisture. Variety lodging, plant population, yield, and seed count were compared by analysis of variance. Means separation was determined by the protected least significant difference test.

Results and Discussion

The soybeans in 2007 were planted earlier than in the past and emergence started on May 21, the earliest since 2002. Plant height and lodging in 2007 were on average the highest since 2005 (Tables 1-3). In 2007, only two varieties had lodging of 5 or less on a scale of 1 to 10. The increased plant height and lodging in 2007 could have been due to the earlier emergence, longer vegetative growth stage before floral induction in early to mid-July, and more degree day units. Lodging has also tended to be higher on average with the new planting arrangement.

Yields in 2007 ranged from 49.1 bu/acre for '909' to 69.8 bu/acre for 'M12' (Table 1). Several of the lines had seed counts sufficient for the manufacturing of tofu (<2,270 seeds/lb). Several lines combined high yields, little lodging, and early maturity. Under the new planting arrangement, started in 2005, lines 'M1', M12, 'M13', 'M16', and '608' have had yields higher than 65 bu/acre, lodging less than 8, and seed counts less than 2,270 seeds/lb.

Figure 1. Soybean planting configuration used in 2005-2007, Malheur Experiment Station, Oregon State University, Ontario, OR.

Summary

We have found over the years that high soybean yields can be achieved in the Treasure Valley by employing varieties selected for the environment, high planting rates, modest fertilization, use ofBradyrhizobium japonicum inoculation, proper May planting dates, appropriate irrigation, and timely control of lygus and spider mites.

References

Shock, C.C., R.J. Flock, E.B.G. Feibert, C.A. Shock, A.B. Pereira, and L.B. Jensen. 2005. Irrigation monitoring using soil water tension. Oregon State University Extension Service. EM8900 6pp. http://extension.oregonstate.edu/catalog/pdf/em/em8900.pdf

Table 1. Performance of soybean cultivars in 2007. Cultivars are ranked by yield, Malheur Experiment Station, Oregon State University, Ontario, OR.

Table 2. Performance of soybean varieties from 2005 to 2007. Cultivars are ranked by average yield. Malheur Experiment Station, Oregon State University, Ontario, OR.

Table 3. Performance of soybean varieties from 2005 to 2007, Malheur Experiment Station, Oregon State University, Ontario, OR.

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Last updated  Tuesday June 17, 2008 .