Nitrogen application rate, timing and history effects on nitrous oxide emissions from corn (Zea maysL.)

Abstract

Roy, A. K., Wagner-Riddle, C., Deen, B., Lauzon, J. and Bruulsema, T. 2014. Nitrogen application rate, timing and history effects on nitrous oxide emissions from corn (Zea mays L.). Can. J. Soil Sci. 94: 563–573. Nitrous oxide (N2O) emissions resulting from application of nitrogen (N) fertilizer contribute to the greenhouse gas footprint of corn production. In eastern Canada, corn is a major crop with most N fertilizer applied pre- or at planting. This timing of application results in a lack of synchrony of soil N supply and crop N demand. Matching the amount and timing of application to crop uptake has been suggested as a mitigation measure to reduce N losses, and is an integral part of the 4R Nutrient Stewardship program. This study examined the effect of timing, rate and history of urea-ammonium nitrate application on N2O emissions in corn in 2011 and 2012 at Elora, ON, Canada. Treatments were three N rates (30, 145 and 218 kg N ha−1); two timings (N injected in mid-row at planting and at the 8th leaf stage, V8); two histories (short-term: applying N rate treatments on plots that had received 145 kg N ha−1 in the previous year, and long-term: applying the same N rate to a given plot over the duration of the trial). N2O emissions were measured using static chambers. History of N application did not have an effect on N2O emissions or grain yield. In both years, cumulative N2O emissions during the growing season and corn yields increased significantly with increasing N application rates. In 2011, cumulative N2O emissions were significantly lower when N was applied as side-dress at V8 (0.88 kg N ha−1) compared with planting (2.12 kg N ha−1), with no significant impact on corn grain yield (average 9.1 Mg ha−1). In contrast, in 2012, limited rainfall reduced both N2O emissions and corn grain yield, and neither N2O emission (average 0.17 kg N ha−1) nor grain yield (average 6.7 Mg ha−1) was affected by timing of N application. Applying N as side-dress at V8 instead of at planting and using the recommended N rate were shown to be effective N2O emission mitigation practices without affecting corn yield during a typical wet spring in Ontario.

Soil denitrifier community size changes with land use change to perennial bioenergy cropping systems

“…Corn grain yields were within the lower range for reported Ontario yields (Munkholm et al, 2013), potentially due to wetter (2011) and drier (2012) field conditions than normal over the two growing seasons (Roy et al, 2014). Deen et al (2011) showed increases in PG biomass yields between the second and third years after PG planting at our site, whereas we measured similar yields in 2011 and 2012, indicating the PGs may have reached maximum yield potential.…”

“…Currently, few studies have assessed soil microbial community responses to PG biomass production systems (Hedenec et al, 2014;Liang et al, 2012;Mao et al, 2013Mao et al, , 2011Orr et al, 2015). The highest potential to reduce greenhouse gas emissions from biomass cropping systems is to produce crops with high yields, such as PGs (Sanscartier et al, 2014), which offset the amount of land required for crop production (Kludze et al, 2013). However, if PG biomass production negatively affects soil health as indicated by changes in the potential functioning of microbial communities, large-scale LUC from annual to perennial biomass production may not be as sustainable as originally proposed.…”

“…Average air temperatures over the growing seasons (May-October) were 16.9 and 17.3 • C in 2011 and 2012, respectively (Roy et al, 2014); average air temperatures in spring 2012 were warmer than normal and resulted in earlier emergence of PG crops compared to 2011. Cumulative monthly precipitation was above average prior to the (Roy et al, 2014). Environmental conditions prior to soil sampling directly impact soil gravimetric content measured at the time of sampling (Fig.…”

“…Sampling of soil carbon occurred only two years after PG planting; PGs are expected to be productive for 20+ years, indicating future changes in soil carbon levels may occur. Additionally, Ontario-based land conversion modelling scenarios have estimated a soil carbon decrease of 2.5 % upon miscanthus establishment (Sanscartier et al, 2014), which may have negated potential increases in soil organic carbon. However, high miscanthus yields most likely resulted in increases SOIL, 2, 523-535, 2016…”

“…have been proposed as alternate feedstock crops to corn for biomass-based bioenergy production due to their large biomass yields, reduced nitrogen (N) and water requirements, decreased nutrient leaching, and potential for increased soil carbon (C) storage (BlancoCanqui and Lal, 2009;Foster et al, 2013). Large-scale production of C 4 PGs in Ontario and the northern Corn Belt would require land use change (LUC) from existing cornsoybean rotations to PG biomass cropping systems (Deen et al, 2011;Kludze et al, 2013;Liang et al, 2012;Sanscartier et al, 2014).…”