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United States Department of Agriculture

Agricultural Research Service

Research Project: Increasing Inland Pacific Northwest Wheat Production Profitability

Location: Soil and Water Conservation Research

2011 Annual Report


1a.Objectives (from AD-416)
The goal of this research project is to identify cultural practices and technologies that improve economic viability and environmental sustainability of inland PNW dryland wheat production systems. The specific objectives are fourfold and include:

Objective 1: Develop cropping practices for improving crop water use in dryland production systems and landscapes across PNW agroecological zones. (Pullman all of Obj 1) Sub-objective 1A: Optimize crop establishment practices and crop water use for improving the performance of winter canola. Sub-objective 1B: Improve stand establishment methods for spring canola to minimize weed competition and increase crop water use. Sub-objective 1C: Contrast fall-planted facultative wheat and spring-planted wheat for abilities to suppress weeds and increase yield, profitability, and crop water use. Sub-objective 1D: Determine effects of Russian thistle on crop water use, and production costs and quality of forage spring triticale.

Objective 2: Evaluate cropping system diversification strategies (forage and biofuels) for increasing agronomic performance of agricultural landscapes across PNW agroecological zones. Sub-objective 2A: Determine productivity and profitability of integrating alternative forage and biofuel crops into wheat-based production systems. (Pullman) Sub-objective 2B: Determine production potential of perennial biofuel and forage crops incorporated as riparian buffers in agricultural landscapes. (Pendleton)

Objective 3: Assess how new optical light reflectance spectrometers (advanced technology) can be used to increase cropping system performance in agricultural landscapes. (Pendleton – all of Obj 3) Sub-objective 3A: Apply information from on-combine yield monitors and optical sensors into site-specific nitrogen (N) application thereby improving grain quality and yield, and N use efficiency of cereal crops. Sub-objective 3B: Assess the quantity and quality of wheat residue at site-specific field locations across farm fields. Sub-objective 3C: Measure and map determinants of grain quality value (i.e. test weight, protein concentration, and foreign weed material), and apply this information into grain segregation on a combine harvester.

Objective 4: Synthesize available crop and cropping systems research across PNW agro-ecological zones to assess biophysical production factors influencing cropping system performance and ecosystem services. Sub-objective 4A: Compile and summarize existing databases of dryland crops and cropping systems to calibrate and corroborate process-oriented models. (Pendleton) Sub-objective 4B: Utilize existing datasets and process-oriented models to spatially evaluate the suitability of past, present, and future cropping system strategies. (Pullman). Replaces 5356-13210-002-00D (10/08). NP216 Cross-location project associated with Pullman, WA, 5348-22610-002-00D (Young).


1b.Approach (from AD-416)
Field experiments will assess the production potential of perennial bioenergy and forage crops in lower, middle, and upper slope positions. Biomass will be harvested at each slope position. Soil/air temperature and rainfall will be measured daily. Soil samples will be analyzed for water content and soil organic matter. A water gradient experiment will study the effect of the water-by-N interaction on grain protein and yield of spring wheat. A second experiment will compare economic returns from precision vs. conventional uniform N placement. Precision N placement uses yield and protein values from the water gradient study to compute the total N required for a following crop. Previous year’s plots of the water gradient study will be replanted. N fertilizer will be applied to half of plots based on N factors computed from previous protein/yield measurements (precision N placement), and to remaining plots based on single uniform N rate (uniform N placement). Uniform and precision N placement will be compared in terms of uniformity in grain protein. Dollar returns will be determined using a partial budget analysis of market quotes and production costs. Grain yield and N supply will be computed for each plot and averaged to arrive at N use efficiency for each N placement strategy. The bulk tank of a combine will be divided into two bins. An optical sensor will sense grain protein and control a mechanism that diverts grain into a bin for ordinary grain or one for high quality grain. Site-specific measurements of grain protein and yield will be used to determine the dollar value of grain. Partial budget analysis will be conducted to compare the profitability of wheat production with and without grain segregation. The water gradient study will provide a wide range in values for yield, grain protein, plant height, and straw yield. Linear regression will be used to develop straw yield prediction equations that include terms for yield, protein, and plant height. Models will be evaluated by comparing predictions against actual measurements obtained from fields. On-combine measurements of grain yield, protein, and straw yield will be obtained using a yield monitor, optical grain quality sensor, and crop height sensor. Maps of straw yield will be used with current price quotes to estimate the net value of straw. Dollar returns will be contrasted with contract payments that would be received under conservation programs if straw is retained. Amount of carbon to maintain soil organic C at current levels will be estimated using the C sequestration model CQESTR. From this, the amount of straw that may be removed while maintaining soil quality will be assessed. Long-term studies will be examined to assess their value for calibration and corroboration of various simulation models (CQESTR, C-Farm, CropSyst, and RZWQM2). For RZWQM2, relevant soil, weather, and plant growth parameters will be calibrated from available data that have measured values of phenology, biomass, and leaf area at different stages, and yield. Modeling will extend study results for a more diverse set of weather conditions and soil types across the region.


3.Progress Report
Progress was made on all of the first two objectives and their subobjectives. Under Objective 2B, we made significant progress in monitoring perennial biofuel and forage crops for growth and development, and measuring growth determining factors and crop yields. This information was acquired for the low-, intermediate-, and high-rainfall zones in the inland Pacific Northwest. Under Objective 3A, we made significant progress in comparing conventional uniform N and spatially variable N placement in terms of agronomic and economic returns. Progress was also made in developing and optimizing standard protocols for molecular analysis of regional soils, and collecting soil samples for microbial diversity and functional gene analyses relative to determining N mineralization and fertilizer use efficiency. Under Objective 3B, we compiled an extensive database consisting of wheat protein levels and yields from numerous hard red spring and soft white winter wheat fields in Oregon and Montana. Stepped price functions, grain protein, and grain yield distributions were used to calculate the profit maximizing cutoff value between two lots of grain segregated on the basis of protein concentration. We made significant progress in determining whether there were profit opportunities for growers from grain segregation by protein concentration. Under Objective 3C, we made significant progress in estimating straw yield from maps of grain yield, grain protein, and crop height, and determining amounts of marketable straw beyond soil conservation needs. We made progress in investigating Light Detection and Ranging (LIDAR) for ability to estimate wheat biomass from measurements of average crop height over a profile scanning in front of a moving combine.


4.Accomplishments
1. Increasing yield and economic returns from intensive cropping under no-tillage. Under intermediate rainfall (14 to 18 in.), growers in northeastern OR are interested in using spring crops to intensify their cropping systems. ARS scientists in Pendleton, OR, compared crop yields, production costs, and economic returns of an intensive, 4-yr rotation under minimum tillage with cultivation by chiseling, sweeping, and rod weeding; versus no-tillage with chemical control. The rotation was fallow-winter wheat-dry spring pea-winter wheat in which a spring broadleaf crop is included to aid in the control of winter annual weeds and reduce pathogen levels of soil-borne cereal diseases. Production using no-tillage was significantly more effective at reducing runoff and soil erosion, with no reduction in yield, and was substantially less costly in labor and fuel requirements than production using minimum tillage. These results indicate that no-tillage has the potential to be economically viable for intensive cropping in the intermediate rainfall region of northeastern OR.

2. Measuring wheat nitrogen (N) status using a green scanning laser. Remote sensing of crop canopy reflectance is useful for determining crop N status and applying N fertilizer in accordance with plant N demand. However, soil background reflectance can confound remote sensing, especially during early stages of crop growth. To overcome this problem, researchers at ARS in Pendleton, OR, and University of Idaho co-investigated the capability of a green laser scanner to quantify levels of leaf chlorophyll in spring wheat. The laser scanner measured the intensity of reflected laser light within a mm-scale instantaneous field of view at a sampling rate of 50,000 points per second. Laser readings were more highly correlated with leaf chlorophyll during early crop growth stages than hand-held chlorophyll meters and tractor-mounted light sensors. This creates opportunities for growers to further improve their N management.


Review Publications
Long, D.S., Scharf, P.A., Pierce, F.J. 2011. Narrow-width harvester for switchgrass and other bioenergy crops in experimental plots. Agronomy Journal. 103:780-785.

Williams, J.D., Long, D.S. 2011. Intensive crop rotation yield and economic performance in minimum tillage and no-tillage, in northeastern Oregon. Crop Management. Available: http://plantmanagementnetwork.org/cm/element/sum2.aspx?id=9430

Long, D.S., Engel, R.E. 2011. Computing wheat nitrogen requirements from grain yield and protein maps. In: Clay, D.E., Shanahan, J.F., editors. GIS applications in agriculture. Vol 2. Boca Raton, FL: CRC Press. p. 321-335.

Eitel, J.U., Vierling, L., Long, D.S., Hunt Jr, E.R. 2011. Early season remote sensing of wheat nitrogen status using a green scanning laser. Agricultural and Forest Meteorology. 151:1338-1345.

Eitel, J.U., Vierling, L., Long, D.S., Litvak, M., Eitel, K.C. 2011. Simple assessment of needleleaf and broadleaf chlorophyll content using a flatbed color scanner. Canadian Journal of Forest Research. 41:1445-1451.

Williams, J.D., Wuest, S.B. 2011. Tillage and no-tillage conservation effectiveness in the intermediate precipitation zone of the inland Pacific Northwest, United States. Journal of Soil and Water Conservation. 66(4):242-249.

Eitel, J.U., Vierling, L., Long, D.S. 2010. Simultaneous measurements of plant structure and chlorophyll content in broadleaf saplings with a terrestrial laser scanner. Remote Sensing of Environment. 114:2229-2237.

Last Modified: 7/30/2014
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