Rye–Corn Silage Double-Cropping Reduces Corn Yield but Improves Environmental Impacts

• Published in: Agronomy journal 2012-07, Vol.104 (4), p.888-896
• Main Authors: Krueger, Erik S, Ochsner, Tyson E, Baker, John M, Porter, Paul M, Reicosky, Don C
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; autumn; Biological and medical sciences; Cereal crops; continuous cropping; Corn; Corn silage; corn soils; crop yield; dairies; double cropping; Environmental impact; fertilizer rates; forage; forage production; Fundamental and applied biological sciences. Psychology; nitrate nitrogen; planting date; rye; Secale cereale; silt loam soils; soil organic carbon; soil solution; spring; vegetation cover; Zea mays
• ISSN: 1435-0645; 0002-1962; 1435-0645
• DOI: 10.2134/agronj2011.0341

Recent proliferation of large dairies has prompted concern regarding environmental impacts of associated corn silage production and high-rate manure application. Our objectives were to compare environmental impacts and forage production of monocrop corn (Zea mays L.) silage and rye (Secale cereal L.)–corn silage double-crop systems with multiple corn planting dates and high-rate manure application near Morris, MN. From 2007 to 2009, corn for silage was seeded into a silt loam as a monocrop in early and mid-May and as a double-crop after rye in mid-May and early June. Manure was fall applied annually at average total N and P rates of 393 and 109 kg ha−1, respectively. Double-cropping reduced total forage dry matter (DM) yield 2 of 3 yr and reduced corn DM yield 15 to 25%. Soil NO3–N to 90 cm accumulated at an average rate of 71 kg N ha−1 yr−1 with monocropping, but accumulation was not observed with double-cropping. Soil organic C concentration from 0 to 5 cm increased in the monocrop (18%) and double-crop (26%) systems over 3 yr. Average soil solution NO3–N concentration was high with monocropping (52 mg L−1) and double-cropping (37 mg L−1), but estimated leaching load averaged only 8 kg ha−1 yr−1. Fall and spring ground cover was often less than 10% with monocropping but was usually greater than 30% with double-cropping. The primary environmental concerns identified for monocrop corn silage were soil NO3–N buildup and inadequate ground cover. Double-cropping addressed each concern but often decreased forage production.