Winter Pea: Promising New Crop for Washington's Dryland Wheat-Fallow Region

Abstract

A 2-year tillage-based winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) rotation has been practiced by the vast majority of farmers in the low-precipitation (<300 mm annual) rainfed cropping region of east-central Washington and north-central Oregon for 140 years. Until recently, alternative crops (i.e., those other than WW) so far tested have not been as economically viable or stable as WW-SF. A 6-year field study was conducted near Ritzville, WA (292 mm avg. annual precipitation) to determine the yield and rotation benefits of winter pea (Pisum sativum L.) (WP). Two 3-year rotations were evaluated: WP-spring wheat (SW)-SF vs. WW-SW-SF. Winter pea yields averaged 2,443 vs. 4,878 kg/ha for WW. No fertilizer was applied to WP whereas 56 kg N and 11 kg S/ha were applied to WW. Winter pea used significantly less soil water than WW. Over the winter months, a lesser percentage of precipitation was stored in the soil following WP compared to WW because: (i) very little WP residue remained on the soil surface after harvest compared to WW, and (ii) the drier the soil, the more precipitation is stored in the soil over winter. However, soil water content in the spring was still greater following WP vs. WW. Soil residual N in the spring (7 months after the harvest of WP and WW) was greater in WP plots despite not applying fertilizer to produce WP. Spring wheat grown after both WP and WW received the identical quantity of N, P, and S fertilizer each year. Average yield of SW was 2,298 and 2,011 kg/ha following WP and WW, respectively (P < 0.01). Adjusted gross economic returns for these two rotation systems were similar. Based partially on the results of this study, numerous farmers in the dry WW-SF region have shown keen interest in WP and acreage planted WP in east-central Washington has grown exponentially since 2013. This paper provides the first report of the potential for WP in the typical WW-SF region of the inland Pacific Northwest (PNW).

New winter crops and rotations for the Pacific Northwest low‐precipitation drylands

“…Size of individual plots was 5 by 30 m (Figure 8). A detailed description of all field operations for the experiment are reported in Schillinger (2017) and are summarized here. For the WW-SW-F treatment, fertilizer was applied for WW.…”

“…Current WP cultivars have an upright growth habit (i.e., they do not lay down or lodge) and can be planted and harvested with drills and combines used for wheat production. Finally, WP is a reliable crop that provides consistently decent yields in both wet and dry crop years (Schillinger, 2017).…”

Integrating Historic Agronomic and Policy Lessons with New Technologies to Drive Farmer Decisions for Farm and Climate: The Case of Inland Pacific Northwestern U.S.

“…As an example, advancement of chickpea (Cicer arietinum) storage, transportation and marketing in the region has greatly expanded iPNW chickpea production, driven by high prices (Maaz et al, in press). Similarly, the varietal development of edible winter dry peas promises to expand legume acreage into the drier agroecological zones, due to their greater yield potential and ability to survive harsh winters (Schillinger, 2017). Fall-sown dry peas and lentils are well-adapted for direct seeding into standing stubble and increasing demand for cover crop pea seed provides production incentive.…”

“…Replacing spring crop sequences with fall-sown winter hardy crops intensifies rotations by providing overwinter soil cover with increased yield potential (Schillinger, 2017;Stöckle et al, 2017). Fall-sown crops mature earlier than spring-sown crops, thereby avoiding heat stressors and water deficits that may occur later in the growing season.…”

“…Yet, it also exhibited poor N balances (Pan et al, 2001) and it was found to be economically less viable than conventional wheat-fallow (Young et al, 2015), thus judged to be an overall lose-neutral scenario. These findings have led to evaluations of diversified crop rotations with winter canola and winter peas (Young et al, 2014;Schillinger, 2017) produced in concert with minimum or no-tillage (Figure 6). …”