This project plan describes cropping systems research conducted jointly by the Soil and Water Conservation Research Unit (Pendleton, Oregon) and the Land Management and Water Conservation Research Unit (Pullman, Washington). The purpose of this project is to advance oilseed production reliably into drier areas in the Columbia Plateau of the interior Pacific Northwest (PNW). Specific objectives are listed below. Objective 1: Identify cultural practices for expanding oilseed production in the drier acreage portions of Columbia Plateau (Pullman, all of Obj 1). Sub-objective 1A: Assess the effectiveness of crop residues and the stripper header for maintaining soil moisture for tillage-based and chemical fallow systems. Sub-objective 1B: Identify best varieties and crop management practices for optimizing seed yield and quality attributes, and managing weeds in spring oilseeds. Objective 2: Identify and evaluate dryland cropping systems comprised of cereals and oilseeds that can be used to produce biofuels and derive environmental benefits (Pendleton all of Obj 2). Sub-objective 2A: Evaluate the yield performance of cereal-based rotations that include oilseeds. Sub-objective 2B: Determine whether diversified wheat-oilseed rotations compared to WW-SF provide belowground benefits derived from changes in microbial communities. Sub-objective 2C: Measure dust and PM10 emissions from diversified crop rotations. Sub-objective 2D: Determine the effect of crop sequences on overwinter infiltration, rain capture, and soil water storage for spring crops. Sub-objective 2E: Calibrate and use SWAT to determine potential changes in crop productivity, hydrology, and sediment loads resulting from a shift from conventional to diverse cropping systems. Objective 3: Compare farm income from conventional winter wheat-summer fallow with diversified cropping systems (Pendleton and Pullman). Objective 4: Conduct life cycle assessments of different cultural practices and dryland cropping systems to evaluate resource use, energy efficiency, water consumption, greenhouse gas (GHG) emissions, and waste production (Pendleton and Pullman).
(Pullman only) 1A: Hypothesis-Soil moisture will be increased in chemical fallow by planting winter triticale and harvesting with a stripper header compared to a winter wheat-tillage fallow system. The study consists of four cropping/harvesting systems in a randomized complete block design with four replications. The systems include; the traditional fallow-winter wheat with wheat harvested using a conventional header, chemical fallow-winter wheat with wheat harvested with a stripper header, chemical fallow-winter triticale harvested with a conventional header, and a stripper header. The long-term goal of this study is to plant winter canola into chemical fallow when soil moisture is 4 to 6 cm from the surface compared to summer fallow where soil moisture is >13 cm deep. Data collected includes crop yield and biomass, gravimetric soil water content (spring and post-harvest) to 1.8 m, organic matter and, soil profile NO3-N and NH4-N to 1.2 m. Water use efficiency will be determined by the ratio of crop yield to spring soil water content minus post-harvest soil water content. Soil water content will be corrected for precipitation. Three 1.8 m soil cores per plot will be composited by 0.3-m increments at each sample date. Analyses of variance (ANOVA) of crop yield, biomass, organic matter, and soil N will be performed using a generalized linear mixed model in PC-SAS with crop rotation as the fixed effect, and replication and crop rotation x replication as random effects. How soon winter canola can be planted will depend on how much residue is produced and how much moisture is received. 1B: Hypothesis—Herbicide-resistant spring canola planted in narrow rows will improve crop yield and oil quality compared to either the same varieties planted in wide rows or spring carinata planted in both row spacings. This study will compare the grain yield and oil quantity of two spring oil seed crops, B. napus canola and B. carinata, planted in two row spacings. Oilseed crops include; “Genuity” early and late maturing spring canola B. napus; “InVigor” spring canola B. napus; and, “Resonance A100” spring B. carinata. “Genuity” spring canola is resistant to Roundup and “InVigor” spring canola is resistant to Liberty herbicides. “Resonance A100” is not an herbicide resistant variety of spring carinata. Crops will be planted mid-April with a JD9400 no-till drill at 5.5 kg/ha in row spacings of 17 and 34 cm. Treatments will be replicated 4 times and arranged in a RCB design. Varieties are main plots and row spacings are split-plots. Crop populations will be determined by counting plants in 2 rows in five 1 m lengths in each plot. Crop yield will be determined by machine harvest. Oil quality and quantity will be determined using a scaled oil extractor to simulate industrial scale processing. ANOVA of crop yield and seed oil content will be performed using a generalized linear mixed model in PC-SAS. Fixed effects will be crop, row spacing, and their interaction. Field experiments are subject to weather variances and the studies may have to be extended in duration. Random effects will be replication and crop x replication. Objectives 3 and 4 will be joint efforts.
During FY15 we conducted winter canola variety trials throughout the low-rainfall, winter wheat production area; winter canola establishment in high residue, stripper header conditions; and management of feral rye in winter canola. These research projects all support Objective 1 to identify cultural practices for expanding oilseed production in the drier acreage portions of the Columbia Plateau. Fourteen canola varieties were planted at three locations in Washington. Varieties were from two university breeding programs, European countries, and private seed companies. Varieties included herbicide tolerant varieties as well as conventionally bred varieties. In general, establishment was >4.0 (1 being poor and 5 being excellent) for most varieties at all locations. We are conducting collaborative research with Washington State University and Adams and Rock Lake Conservation Districts to evaluate the use of a stripper header to increase residue to retain soil moisture. In the fall of 2014 we no-tilled winter canola into 3-ft high standing winter triticale stubble harvested with a stripper-header. Because of hot, dry fall conditions, stand establishment in the tall, stripper header stubble was only 35%, however stand establishment in the traditional fallow was 0%. Spring canola was replanted into the treatments and subsequently was killed by frost.
1. Feral rye control in winter canola. Feral rye is a winter annual grass weed that reduces winter wheat yield >30% and costs U.S. wheat growers $27 million per year. An ARS agronomist at Pullman, Washington, conducted a study from 2010 to 2014 to evaluate the efficacy of three herbicides on feral rye control and winter canola yield. Canola yield and weed control varied with environmental conditions and feral rye density, but in general, fall plus spring applications of quizalofop and glyphosate effectively and consistently increased yield and controlled feral rye. With the integration of winter canola into this region, an opportunity exists to manage feral rye while improving grower diversity and sustainability.