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

Abstract

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 highrate 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 aft er 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 NO 3 -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 NO 3 -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 oft en less than 10% with monocropping but was usually greater than 30% with double-cropping. Th e primary environmental concerns identifi ed for monocrop corn silage were soil NO 3 -N buildup and inadequate ground cover. Doublecropping addressed each concern but oft en decreased forage production.

Corn Nitrogen Fertilization Requirement and Corn-Soybean Productivity with a Rye Cover Crop

“…Krueger et al (2012) indicated that corn yield decrease with RCC was likely a result of the rye-corn rotation affecting corn growth rather than RCC effects on soil supply of PAN, which could have been the case in our study and was confirmed by the relatively small differences in soil profile NO 3 -N between no-RCC and RCC. Corn grain yield decreased as RCC biomass increased.…”

“…However, research has found differing annual crop yield responses with RCC. Corn grain and silage yield decreases have been reported with use of RCC (Raimbault et al, 1990;Kessavalou and Walters, 1997;Thelen and Leep, 2002;Singer and Kohler, 2005;McDonald et al, 2008;Kramberger et al, 2009;Salmerón et al, 2011;Krueger et al, 2012;Reese et al, 2014). A 15% corn yield increase was observed in 2 out of 3 yr in a study conducted on sandy soils in Wisconsin with no N application to the RCC and with low RCC biomass production .…”

On-farm environmental assessment of corn silage production systems receiving liquid dairy manure

“…Results confirmed that, when planted after corn silage harvest, a rye cover crop can provide environmental benefits (Krueger et al 2010;Krueger et al 2011;Krueger et al 2012) without impacting subsequent corn yield even in a cold climate (Krueger et al 2011). Rye/corn silage cropping systems prevented soil NO 3 -N accumulation and reduced soil solution NO 3 -N concentration compared with corn silage alone, while also increasing ground cover and soil organic C (SOC) relative to corn silage without a cover crop (Krueger et al 2010;Krueger et al 2011;Krueger et al 2012). However, when rye was allowed to grow until it could be harvested for forage (i.e., forage double-cropping), significant reductions in subsequent corn silage yield occurred, primarily resulting from soil moisture and NO 3 -N depletion that increased with greater rye growth.…”

“…With its short growing season, corn silage provides little vegetative cover much of the year (Krueger et al 2012), which leaves the soil prone to erosion by wind and water Abstract: Increased corn (Zea mays L.) silage and manure production accompanying the proliferation of large dairies has prompted concern regarding their environmental impacts. The objectives of this on-farm, field-scale study were (1) to quantify environmental impacts, e.g., soil chemical properties and offsite nutrient transport, of corn silage production with dairy manure application on artificially drained soils and (2) to assess the environmental benefits of and agronomic constraints on the adoption of winter rye (Secale cereale L.) cover cropping by a large dairy in west central Minnesota.…”

“…Winter rye can scavenge excess soil NO 3 -N (Jewett and Thelen 2007) and reduce NO 3 -N leaching (Kaspar 2007;Strock et al 2004), while rye biomass returned to the soil can maintain or increase soil carbon (C) (Kaspar et al 2006;Kuo et al 1997). Rye can increase fall and spring ground cover compared with winter fallow (Krueger et al 2012), which can reduce soil erosion (Kaspar et al 2001) and off-site nutrient transport. Still, farmers are hesitant to plant cover crops because of associated costs, lack of information, and time constraints arising from the limited growing season in the Upper Midwest, and as a result, cover crop adoption rates are low in the region, with only about 18% of farmers having used cover crops (Singer et al 2007).…”