Location:2012 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.
3. Progress Report:
Measures of the soil C-sequestration potential of irrigated switchgrass production were completed. A manuscript was submitted and was published in the Soil Science Society America Journal. A field trial established in 2008 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 has been completed. Final assessments of the soil nutrient, potato quality and efficacy of bioenergy co-products are being analyzed. Three manuscripts on the use of biochar in soil have been published. Onion field trials for weed suppression have been completed. Mustard meal derived from three S. alba genotypes differing in glucosinolate content were evaluated. Studies of greenhouse gas production in reduced tillage and sillage corn production have been completed and two manuscript published. Validation of the SPUDSIM potato growth simulation model for the irrigated inland Pacific Northwest region gas been completed. Second year potato trials were established on a certified organic field to evaluate a series of organic fertilizers and bioenergy coproducts. Manuscript being prepared on two year field trial comparing sweet corn hybrid tolerance to weeds under different weed management levels including nonchemical approaches applicable to organic farming.
1. Greenhouse gas emissions from soil amended with anaerobic digested dairy manure. Dairy production in the Pacific Northwest has grown steadily over the past decade resulting in large concentrations of animal wastes. These wastes have been implicated in the decline of surface and subsurface water quality as well as an increase in the production of greenhouse gases when used as a soil amendment. Field studies showed that emission rates of greenhouse gases (GHG) were significantly less (60%) than the emission value proposed by the International Panel on Climate Change (IPCC).
2. Biochar amended with dairy effluent maintains recommended phosphorus levels. We demonstrated that biochar amended with dairy effluent applied at 2.5 Ton/acre maintained recommended soluble P levels (1000 ppm) in Ranger and Umatilla potato variety petioles through 60 days after emergence. Biochar additions improve soil pH, water holding capacity and soil C pools. Removal of nutrients by biochar from dairy storage lagoons and used as a supplemental fertilizer off site is a beneficial strategy to reduce nutrient contamination around dairies and supply nutrients for potato production.
3. Biochar added to soil reduces bioavailability of atrazine and metribuzin. We demonstrated that biochar added to two soils reduced the bioavailability of both atrazine and metribuzin. Reduction in herbicidal activity was the result of increased sorption of both herbicides by biochar. This information also allows producers to adjust herbicide rates to counter the reduction in herbicide activity when electing to amend soil with biochar.
4. Identifying herbicide resistant weeds. Weed seed were collected from escape weeds in potato fields throughout the Columbia Basin and were tested for dose response to metribuzin. Fifteen of 27 pigweed biotypes and 8 of 25 common lambsquarters biotypes were resistant to metribuzin ranging from 2 to 142 fold more herbicide required to provide 90% control compared to the susceptible biotype. This information provides producers with knowledge to improve herbicide selection and weed management practices that delay, prevent, and manage herbicide resistant weeds.
5. Minor yield losses in potato using deficit irrigation. Cost of potato irrigation in the Columbia basin is approximately 10% of total cost of production. Yield reduction in Ranger Russet and Umatilla Russet cultivars was 7 to 10% with 14 to 17% deficit irrigation as compared to the yield with irrigation to replenish full evapotranspiration. Major yield loss with deficit irrigation was associated with reduction of >8 oz size tubers.
6. Polymer coated fertilizers reduce N fertilizer rates. Pre-plant application of 200 lbs N/acre as polymer coated urea PCU, (Complete or 50/50 mix of PCU/urea) produced similar tuber yield (about 35 tons/acre) of Umatilla Russet cultivar as compared to that with conventional fertilization practices of 300 lbs N/acre, i.e. 100 lbs N/acre urea pre-plant and five fertigations of UAN at 200 lbs N/acre.
7. Low frequency fertigations (application of fertilizer) more efficient than high frequency. Under conventional nitrogen management for potatoes in the lower Columbia Basin, the optimal N management is 100 lbs N/acre as urea pre-plant soil applied plus 200 lbs N/acre in five fertigations as UAN at two weeks interval, four weeks after seedling emergence. Increased frequency of in-season fertilization (i.e. 10 or 20) failed to provide any additional benefits.
Lange, B., Mahmoud, S., Wildung, M., Turner, G., Davis, I., Baker, R., Boydston, R.A., Croteau, R. 2011. Improving peppermint essential oil yield and composition by metabolic engineering. Proceedings of the National Academy of Sciences. 41:16944-16949.