Grain Yield and Returns from Intercropping Wheat and Flax

Intercropping hard red spring wheat (Triticum aestivum L.) with flax (Linum usitatissimum L.) could offer advantages over monocropping in dry regions of northern latitudes. Our objective was to determine if wheat yield could be maintained while also producing an economic yield of flax. Two high yielding wheat cultivars, 'Amidon' and 'Grandin', were sown at 65 lb/acre in a monoculture and intercropped with 'Linton' flax sown at 32 lb/acre. North Dakota dryland management was used in 1989 and 1990, but supplemental irrigation also was evaluated in 1990. Intercrop patterns included establishment of both crops in the same row, in alternate rows, and in plots where flax was broadcast seeded into wheat. An additional intercrop pattern was included during 1990; flax and wheat were seeded in rows perpendicular to each other. Compared with sole cropping, intercropping reduced flax yield more than 90%, and sometimes reduced wheat yield by almost 25% (P < 0.05). Economic returns were generally greater for a monoculture of wheat or flax than for intercrops. Land equivalent ratios (LERs) failed to indicate any advantage for intercropping. This study shows that an economic flax yield is not produced when a monoculture wheat population (app. 20 plants/sq ft) is established in a wheat-flax intercrop. Work is needed to determine if the economic performance of wheat-flax intercrops is improved when the seeding rate for wheat is considerably less than in a monoculture.