Economic returns from three‐year crop rotations under low precipitation in Pacific Northwest

Abstract

Some producers in the inland Pacific Northwest (PNW) are interested in diversifying the traditional 2‐yr sequence of winter wheat (Triticum aestivum L.) (WW)–summer fallow (SF) with oilseed crops to capture break crop effects. The objective of this study was to compare production costs and economic returns of 2‐yr sequences with those of intensified 3‐yr sequences at a low‐precipitation (<300 mm) site where the long‐term rotation has been WW‐SF. A 5‐year (2014–2018) cropping sequence study was conducted that included summer fallow with intensive tillage (SF) and reduced tillage (RTF) in 2‐yr rotations with WW; and RTF in 3‐yr rotations with WW, winter canola (WN; Brassica napus L.), or spring carinata (SC; Brassica carinata A. Braun) as a primary crop and spring wheat (SW), spring barley (SB; Hordeum vulgare L.), or SC as a secondary crop. Reduced tillage fallow increased WW yields by 14% compared with SF. Production of WN and SC in WN‐SW‐RTF and SC‐SW‐RTF, expressed by equivalent WW yield, was 42%, and 35% of WW in WW‐RTF vs. 67% needed to compensate for 1/3 less cropping with WW. Production of SC in WW‐SC‐RTF was 21% of WW in WW‐RTF vs. 33% needed to compensate. Mean net returns over total costs were negative with WW‐RTF least unprofitable at −US$162 ha−1 followed by WW‐SB‐RTF at −$167 ha−1, WW‐SF at −$180 ha−1, WW‐SC‐RTF at −$191 ha−1, SC‐SW‐RTF at −$205 ha−1, and WN‐SW‐RTF at −$229 ha−1. Including oilseeds in 3‐yr rotations with WW and fallow apparently may be less profitable than WW in 2‐yr rotations with fallow.