47-17 Double Cropping with Pea-Barley Biculture and Early-Maturing Corn As a Low N Alternative to Sole-Crop Corn in Minnesota.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Agricultural Practices to Improve Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emission Oral

Monday, November 7, 2016: 1:45 PM
Phoenix Convention Center North, Room 226 C

Daniel Raskin, 1991 Buford Circle, University of Minnesota, Saint Paul, MN, M. Scott Wells, 1991 Upper Buford Cir, University of Minnesota, St Paul, MN, Julie Grossman, Horticultural Sciences, University of Minnesota, St. Paul, MN and Craig C. Sheaffer, Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN
Abstract:
Double-crop systems with cool season forages can increase yields and land- and resource- use efficiency over sole-crop summer annual rotations. Commonly, a cool-season forage crop is followed by a primary, warm-season crop. Minnesota’s short growing season limits growing degree units (GDU) and limits yield, necessitating a double-crop system that prioritizes economic value rather than season extension. This study assessed whether the combination of high value, forage, early maturing corn varieties, and reduced N fertilizer inputs constitutes a viable, low N-input double crop system for Minnesota. Two double-crop (DC) and one sole-crop (SC) rotations where studied from 2014 to 2016 at three locations in Minnesota. In DC rotations, a pea- (Pisum sativum L.) barley (Hordeum vulgare L.) bi-culture was double-cropped with early-maturing hybrid (DC-HC) or semidwarf (DC-SD) corn varieties as a primary crop. In SC rotation, full-season hybrid corn (SC-HC) was planted with no preceding forage. Corn was supplied with 6 N rates (0 to 224 kg N ha-1). Biomass yield, N uptake, and residual soil N were measured for each yield component. Mean biomass yield of DC-SD was low (1.8 Mg ha-1) and showed no response to N rate. Corn yielded less biomass in DC-HC (8.2 Mg ha-1) and DC-SD (1.8 Mg ha-1) treatments yielded compared to SC-HC (16.3 Mg ha-1). Biomass yield deficits lowered corn N demand in DC-HC treatments so that N rates >166 kg N ha-1 did not limit biomass yield in DC-HC treatments, where SC-HC corn was limited by N rate in three of four site-years. Total biomass accumulation was similar between DC-HC and SC-HC treatments when forage bi-culture yielded >7 Mg ha-1.This suggests that double-cropping with high-quality forages may constitute an economically viable low N-input alternative to sole-crop corn production in Minnesota.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Agricultural Practices to Improve Nitrogen-Use Efficiency and Mitigate Greenhouse Gas Emission Oral