Location:2013 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:
This is the final report for this project which has been replaced by 5354-21660-003-00D, "Enhancing Sustainability of Irrigated Specialty Crops and Biofuel Feedstock Production". 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 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 have been completed. 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 silage 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. Organic potato production trials were completed on a certified organic field to evaluate a series of organic fertilizers and bioenergy co-products. Economic assessments were not completed however we are soliciting an agriculture economist from Washington State University to assist in data analysis of the organic potato production studies. Field trials comparing sweet corn hybrid tolerance to weeds under different weed management levels including nonchemical approaches applicable to organic farming have been completed and manuscripts published.
1. Soil microbial population response to land conversion. A native shrub–steppe ecosystem converted to a series of irrigated organic agricultural fields was evaluated for biological indicators that signaled changes in soil processes during the initial stages of land conversion. Cultivated fields had greater microbial populations and were more biologically active compared to native sites. Microbial characteristics were influenced more by conversion of the native ecosystem to an irrigated agroecosystem and the addition of compost than by the length of time of cultivation. This research benefits organic growers developing production systems on new farmland and provide them insights on how manage soil microbial populations.
2. N uptake by potato under irrigated organic cropping systems. Organic production systems have been shown to improve soil organic matter and stimulate nutrient cycling through enhancement of the soil microflora. Nitrogen released from each of eleven commercial organic fertilizers and compost amendments averaged 25 lb N/acre from April through August, with minor differences between fertilizers. Petiole P and K were maintained above recommended levels throughout the season. This study provides organic potato growers information on the nutrient availability of a diverse array of commercial organic fertilizers. The fertility value of fertilizers tested was shown to be similar, providing organic potato growers’ useful information on fertilizer performance rather than testimonials provided by fertilizer suppliers.
3. Competition between crop and weed plants likely co-occurs in many sweet corn fields. In field studies, two hybrids with different levels of tolerance to weed competition were planted at five seeding levels and grown in the presence and absence of wild proso millet. The crop’s ability to tolerate intraspecific and interspecific competition was additive for time to silk, ear number, ear mass, and gross profit margin to the processor. Hybrids showed differential tolerance to interspcific competition, at the seeding levels tested neither hybrid was consistently more tolerant to intraspecific competition. These studies suggest that greater seeding levels could be utilized by growers to maximize marketable ear number and mass, and gross profit margins to the processor.
4. Weeds lower yield and quality of potatoes left uncontrolled. Three new herbicides were tested in potato to determine potato tolerance and weed control. Pyroxasulfone and saflufenacil applied preemergence alone and in tank mixes with currently labeled herbicides did not injure potatoes. Pyroxasulfone controlled barnyardgrass, hairy nightshade, and redroot pigweed equal to or greater than currently labeled herbicides. Saflufenacil controlled common lambsquarters, hairy nightshade, and redroot pigweed at one of two sites equal to that of currently labeled herbicides. These studies indicate that pyroxasulfone and saflufenacil could be useful herbicides for weed control and management of herbicide resistant weed populations in potatoes.Felix, J., Boydston, R.A., Burke, I. 2012. Response of direct-seeded dry bulb onion to simulated glyphosate drift with variable rates and application timings. Weed Technology. 26:747-756.