Establishment and Growth of Self-Seeded Winter Cereal Cover Crops in a Soybean–Corn Rotation

Abstract

Perpetuating cereal cover crops through self-seeding may increase adoption by reducing risk and cost. Winter rye (Secale cereale L.), wheat (Triticum aestivum L.), and triticale (× Triticosecale Wittmack) were used to develop self-seeding cover crop systems in a soybean [Glycine max (L.) Merr.]–corn (Zea mays L.) rotation. Cereals were planted and managed chemically and mechanically in varying configurations. The objectives were to (i) quantify temporal establishment patterns after one cycle of self-seeding, (ii) quantify shoot biomass, N uptake, and seed production growing concurrently with corn, and (iii) quantify cover crop establishment after two cycles of self-seeding. Final plant densities for most species by treatment combinations were fully established within 1 wk after soybean (Cycle 1) harvest. Fall green ground cover after soybean was consistently higher with wheat and ranged from 16 to 61%. Straw biomass the following July ranged from 50.4 to 79.1 g m−2 in wheat, 20.1 to 39.3 g m−2 in triticale, and 0.0 to 52.7 g m−2 in rye. Combined spring and maturity maximum N uptake was 20.7, 21.2, and 35.0 kg ha−1 for triticale, wheat, and rye. Cycle two cover crop seed production was greatest in wheat and ranged from 559 to 1280 seeds m−2. Wheat also consistently had greater self-seeding plant establishment after two cycles than rye and triticale, which ranged from 5 to 21% of the original plant densities and 19 to 64% of the cycle one plant densities. Future research on self-seeding cereal cover crops should focus on efficient technologies for seed dispersal.