On-farm environmental assessment of corn silage production systems receiving liquid dairy manure
2013
Krueger, E. S. | Baker, J. M. | Ochsner, T. E. | Wente, C. D. | Feyereisen, G. W. | Reicosky, D. C.
Increased corn silage and manure production accompanying the proliferation of large dairies has prompted concern regarding their environmental impacts. Our objectives were (1) to quantify soil chemical properties and offsite nutrient transport under field-scale corn (Zea mays L.) silage production and high-rate manure application on artificially drained soils and (2) to assess the environmental and agronomic impacts of a winter rye (Secale cereal L.) cover crop within this cropping system near Morris, MN. From 2007-2009, corn for silage was grown on two adjacent 65 ha fields with rye planted after corn on one field in 2007. Manure was fall applied annually at average total N and P rates of 410 and 98 kg ha-1, respectively. Drainage NO3-N concentration was reduced from 53 mg L-1 before rye to 38 mg L-1 after rye, but rye had no apparent effect on DRP concentration or drainage volume. Annual NO3-N and dissolved reactive phosphorus (DRP) loads averaged 52 and 0.8 kg ha-1 yr-1, respectively. Soil nutrient accumulation did not occur, and soil organic carbon (SOC) and total nitrogen (TN) were maintained or increased with or without rye. Rye reduced spring soil NO3-N by 46% compared with winter fallow but did not impact Olsen P. Rye increased ground cover, but corn dry matter (DM) yield was 16% lower after rye than after winter fallow. Offsite nutrient transport and limited ground cover with corn silage production suggest alternative management strategies are needed, but possible corn DM yield reduction after winter rye makes it a risky option.
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