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United States Department of Agriculture

Agricultural Research Service


Location: Vegetable and Forage Crops Production Research

2010 Annual Report

1a.Objectives (from AD-416)
Objective 1: Identify optimal strategies for incorporating bioenergy crops into irrigated Pacific Northwest Region cropping systems. • Sub-objective 1.A. Evaluate the impacts of harvest of C3 and C4 grass perennial biomass crops and the removal of crop residues on carbon sequestration, nutrient dynamics, and soil quality in irrigated Pacific Northwest crop rotations. • Sub-objective 1.B. Determine the efficacy of co-products from agricultural-based energy production on weed and disease control and soil fertility improvement in irrigated crop production systems. Objective 2. Identify optimal combinations of management practices to lower total production costs while maintaining market quality of irrigated potato-based production systems. • Sub-objective 2.A. Determine the impact of reduced tillage on soil conservation/erosion soil physical properties, the mechanisms controlling carbon and nitrogen cycling, and trace gas (CO2, N2O, CH4) fluxes and C sequestration and the yield and quality response of potato and rotational crops. • Sub-objective 2.B. Evaluate the effects of deficit irrigation practices on potato yield and tuber quality. • Sub-objective 2.C. Validate the ARS Potato Growth Simulation Model for the irrigated inland Pacific Northwest region. Objective 3. Develop ecologically-based management strategies that enhance vegetable yields and soil quality in irrigated organic production systems. • Sub-objective 3.A. Quantify key soil agroecological processes (carbon and nitrogen cycling) and application rates of organic amendments that optimize physiological development (nitrogen capture, plant growth rate) of potato under irrigated organic cropping systems. • Sub-objective 3.B. Integrate hybrids with weed suppressive traits into organic specialty crop production systems.

1b.Approach (from AD-416)
Long-term sustainability of potato production in the Pacific Northwest will depend not only on balancing the physiological production requirements, but also overcoming additional constraints to system productivity and profitability. Assessing sustainability and the basic interactions among system components are multifaceted tasks that require long-term studies integrating a multidisciplinary approach to understand system constraints and also provide data needed to support evaluation of impacts of specialty crops by system modelers. Improved cropping systems will be developed that reduce erosion, reclaim excess N, build organic matter, and suppress pests and improve soil and environmental quality and economic viability. Application of conservation tillage to specialty cropping systems will be investigated to evaluate improving environmental, biological and economic sustainability. With the expansion of the bioenergy industry in the U.S. and state and regional mandates for biofuel blending have made biofuels a high priority issue for the USDA. The expansion of the biofuel industry on potato and other specialty crop production will be investigated. The projected growth of the ethanol and biodiesel industries in the PNW will produce large quantities of organic-based co-products. These co-products are much greater than what can be utilized locally as a source of animal feed, so alternative value added uses will be investigated. The use of these co-products could be used to offset the high costs of nutritional and pest control requirements of potato and specialty crops. The demand for organic produce continues to expand and is of increasing interest to PNW growers. Managing weeds and providing adequate nutrients are the two major production issues for organic producers. Economical and environmentally friendly solutions are needed for organic producers to increase production efficiency by management of weeds and nutrients. Formerly 5354-21660-001-00D (8.08).

3.Progress Report
Measurements of above- and below-ground productivity, nutrient export, and C sequestration were made using a combination of field and laboratory studies. Measures of C-sequestration potential by laboratory incubations and 13C analyses were completed for both 2008 and 2009 soil samplings. A field trial evaluating the application of agricultural-based energy co-products (e.g. oil-seed meals, distillers grains, anaerobic digested dairy manures) to reduce the application of synthetic fertilizers was established at the USDA-ARS Field Station in Paterson WA. Second year assessments of the soil nutrient, potato quality and efficacy of each bioenergy co-products are being analyzed. Field trials evaluating weed suppression in organic onions with Sinapis alba seed meal were completed. Sweet corn hybrids differing in weed tolerance and weed suppressive ability are being evaluated among two levels of cultivation in a second year field trial. The influence of biochar on herbicide activity of atrazine and metribuzin was tested using greenhouse oat bioassays. Completed measurements of wind erosion and dust (i.e. PM10) emissions under the reduced and conventional tillage and crop. The studies of greenhouse gas production have been completed and peer-reviewed manuscript published. The field research on the effects of deficit irrigation practices on potato yield and tuber quality has been completed and analyses of data from the field trials are in progress. Potato and corn field experiments under different nutrient management are in progress. Plant samplings are taken at various growth stages for measurement of biomass and nutrients accumulation and partitioning. These data will be used for field validation of crop simulation models.

1. Biochar Research. Biochar is being promoted for its potential to improve soil properties, fertility and carbon sequestration in soil. How this material might impact agricultural soils within temperate regions is largely unknown. Validation of biochar as a beneficial soil amendment and carbon sink would add important economic value to the pyrolysis process and spur adoption. ARS researchers from the Vegetable and Forage Crops Research Unit, Prosser, WA evaluated five bio-chars made from five waste feedstocks for their influence on the soil properties and C sequestration potentials. Biochar was found to increase soil pH, water holding capacity and soil C pools. A 168 pp report was published on line at This information is being requested by local and state economic development agencies as well as growers, consultants and other researchers.

2. Dairy manure as an energy and fertilizer source. The common practice for disposal of dairy manure is application of lagoon water to adjacent agricultural fields which results in nutrient leaching to groundwater or runoff losses to waterways. ARS scientists at the Vegetable and Forage Crops Research Unit, Prosser, WA developed technology to utilize dairy waste as a source phosphorus fertilizer. The co-product, biochar made from the pyrolysis of manure was applied to dairy waste water to capture nutrients. The addition of biochar removed 68% of the phosphorus and 14% of the nitrogen from the dairy waste water within 15 days of application. Dairies in Washington State could produce 230,000 tons of nutrient enriched biochar a year from manure reducing leaching and runoff losses.

3. Biochar affects the activity of two herbicides. Biochar is being utilized as a soil amendment in various cropping systems and may impact the activity of herbicides. Researchers at the Vegetable and Forage Crops Production unit in Prosser, Washington found that adding biochar reduced the activity of two common herbicides used in potato and corn production, which could result in poor weed control. This information can be utilized by producers to modify herbicide rates and prevent weed control failures when utilizing biochar as a soil amendment.

4. Impact of deficit irrigation on potato production and quality. Potato tuber yield and quality are impacted by irrigation and nitrogen (N) management. Deficit irrigation, meaning a 20% reduction in total amount of water applied, resulted in 7-24% tuber yield reduction compared to that of the plants received standard irrigation, where daily water loss from the soil and plants is replenished daily. Yield reduction in deficit irrigation was generally attributed to reduction in large weight tubers, >0.227 kg/tuber. This study demonstrated that modest deficit irrigation, of only 20% total water applied, can result in significant reduction in net returns under high productive growing conditions in the Northwest.

5. Weed-free Crop Rotation reduces Corky Ringspot. Corky ringspot disease (CRS) of potato is caused by tobacco rattle virus (TRV) and vectored by stubby root nematode and makes tubers unmarketable. CRS is present in approximately 5% of the potato acreage of the Columbia Basin and soil fumigation, costing $200/acre, is currently the only method of control. Researchers at the Vegetable and Forage Crops unit in Prosser, WA completed research demonstrating that growing weed-free alfalfa cleanses CRS from soil. Weed hosts of TRV and stubby root nematode were identified, that when present in the crop rotation, prevented the cleansing of TRV from the nematode population. Growers can utilize this research to eliminate or lesson the need for costly soil fumigation, saving approximately $1.5 million dollars to the industry.

6. Weed control important in the eradication of potato cyst nematode. The potato cyst nematode, Globodera pallida (PCN), a restricted pest in the United States, was first reported in Idaho in 2006 and the U.S. government and Idaho State Department of Agriculture hope to eradicate it from infested fields. Eradicating PCN will require depriving the nematodes of their hosts (potatoes, tomatoes, and various weeds) over a protracted time period. The host status of PCN found in Idaho has not been documented and is unknown. Host suitability tests were conducted on common weeds found in the PNW potato production region. Reproduction of PCN occurred on hairy nightshade (Solanum physalifolium) biotypes from Idaho and Washington. Cutleaf nightshade (S. triflorum) (biotypes from Idaho and Washington), black nightshade (S. nigrum) (Washington biotype), bittersweet nightshade (S. dulcamara) (Idaho biotype) were relatively poor hosts of PCN. PCN did not produce new cysts on redroot pigweed (Amaranthus retroflexus), kochia (Kochia scoparia), and common lambsquarters (Chenopodium album). Control of hairy nightshade during the eradication of potato cyst nematode from infested fields will increase the likelihood of success.

5.Significant Activities that Support Special Target Populations
Presented a talk at the 2010 Yakama Nation: Roots for Productivity Workshop in Toppenish, WA. The talk described methods and technologies to increase and improve soil fertility and the quality of soil organic matter. The annual meeting was attended by 60 farmers, crop consultants and researchers from throughout the Yakima Valley and Columbia Basin of Washington and covers a wide variety of specialty crop production issues.

Review Publications
Paramasivam, S., Richards, K.A., Alva, A.K., Sajwan, K.S., Afolabi, J., Richards, A.M. 2009. Evaluation of Poultry Litter Amendment to Agricultural Soils: Leaching Losses and Partitioning of Trace Elements in Collard Greens. Journal Of Water Air And Soil Pollution. 202: 229-243.

Alva, A.K., Marcos, J., Stockle, C., Reddy, V., Timlin, D.J. 2010. A Crop Simulation Model for Prediction of Yield and Fate of Nitrogen in Irrigated Potato Rotation Cropping System. Journal of Crop Improvement. 24: 142-152.

Paramasivam, S., Jayaraman, K., Wilson, T.C., Alva, A.K., Kelson, L., Jones, L.B. 2009. Ammonia Volatilization Loss from Surface Applied Livestock Manure. Journal of Environmental Science and Health. 44: 317-324.

Wang, Q., Li, Y., Alva, A.K. 2010. Growing Cover Crops Improve Biomass Accumulation and Carbon Sequestration: A Phytotron Study. Journal of Environmental Protection. 1: 73-84.

Alva, A.K. 2010. Techniques to Enhancing Sustainable Nutrient and Irrigation Management for Potatoes. Journal of Crop Improvement. 24:281-297.

Macconnell, C.B., Collins, H.P. 2009. Utilization of Re-processed Anaerobically Digested Fiber from Dairy Manure as a Container Media Substrate. Acta Horticulturae. 819: 279-286.

Stockle, C.O., Nelson, R.L., Higgins, S., Brunner, J., Grove, G., Boydston, R.A., Whiting, M., Kruger, C. 2010. Assessment of climate change impact on Eastern Washington agriculture. Climatic Change. Available:

Young, S.L., Pierce, F.J., Streubel, J.D., Collins, H.P. 2009. Performance of solid-state sensors for continuous, real-time measurement of soil CO2 concentrations. Agronomy Journal. 101:1417-1420.

Moore, A.D., Alva, A.K., Collins, H.P., Boydston, R.A. 2010. Mineralization of nitrogen from biofuel byproducts and animal manures amended to a sandy soil. Communications in Soil Science and Plant Analysis. 41:1315-1326.

Last Modified: 4/18/2014
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