SOYBEAN PERFORMANCE IN ONTARIO IN 2006
Clinton C. Shock, Erik B.G.
Feibert and Lamont D.
Malheur Experiment Station
Oregon State University
Soybean is a potentially valuable new crop for the Pacific Northwest. Soybean could 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 could 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 and lodging, reduced plant height, 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. Its objective was to provide a more uniform distribution of the plants over the soil surface. The new planting configuration had 3 plant rows on a 30-inch bed. The more uniform plant distribution resulted in higher yields, perhaps due to improved access to light, nutrients, and water for individual plants.
This report summarizes work done in 2006 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 2006 trial was conducted on a Owyhee silt loam (pH of 7.6 and 0.9 percent organic matter) previously planted to wheat. Twenty-one lb N, 100 lb P, 100 lb S, 2 lb Cu, and 1 lb of boron were broadcast in the fall of 2005. In the fall of 2005, after fertilization, the field was disked twice, moldboard plowed, ground-hogged twice, and bedded to 30-inch rows. On May 26, 2006, 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. The 39 selections were evaluated in 10 ft by 25 ft plots arranged in a randomized complete block design with four replicates. The seed was planted on May 24 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. Emergence started on May 30.
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 Carzol at 0.69 lb ai/acre on July 24 and on July 29, and with dimethoate at 0.5 lb ai/acre and Comite at 1.6 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 7 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
Consistent with previous years, 2006 soybean production at Ontario included inoculation with Rhizobium strains specific to soybeans, control of pests (especially lygus bug and spider mite), modest fertilization, and consistent irrigation. Lack of inoculation or lack of pest control compromises the crop. Heavy fertilization, especially with N, has resulted in severe lodging in growers fields and poor recovery of beans.
Yields in 2006 ranged from 64.4 bu/acre for 'M92-085'' to 81.9 bu/acre for 'Lambert' (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.
On average, yields in 2005 and 2006 were higher than in the previous 3 years (Table 2), possibly as a result of the modified planting configuration. The planting configuration used previously had seeds planted in single rows on 22-inch beds. In 2005 and 2006 there were 3 rows on a 30-inch bed (Fig. 1).
Figure 1. Soybean planting configuration used in 2005 and 2006, Malheur Experiment Station, Oregon State University, Ontario, OR.
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 of Rhizobium japonicum inoculation, proper May planting dates, appropriate irrigation, and timely control of lygus and spider mites.
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. EM 8900 6p. http://extension.oregonstate.edu/catalog/pdf/em/em8900.pdf
Table 1. Performance of soybean cultivars ranked by yield in 2006, Malheur Experiment Station, Oregon State University, Ontario, OR.
|Cultivar||Origin||Days to maturity||Days to harvest maturity||Lodging||Height||seeds/lb||Yield|
|days from emergence||0-10||cm||seeds/lb||bu/acre|
|Cultivar||2005||2006||Average||Days to maturity||Lodging||Height||Seed count|
|--------------- bu/acre ---------------||0-10||cm||seeds/lb|