73-3Precision Manure Injection On Nitrogen Use and N2 O Emissions in Corn.
See more from this Division: ASA Section: Environmental QualitySee more from this Session: Nitrogen-Use Efficiency and Nitrous Oxide Emissions.
Monday, October 22, 2012: 10:30 AM
Duke Energy Convention Center, Room 235, Level 2
Closed slot injection is a proven way to reduce emission of ammonia from slurry manure and hence can increase crop N use efficiency. A recent study has shown that dairy slurry injected precisely near corn rows provides starter and season-long P for corn. However, injecting manure may result in enhanced greenhouse gas emissions due to anaerobic conditions. Here we report on the first two years of a multi-year study designed to evaluate the effect of precision-injection dairy slurry on growth and N uptake by silage corn, and on emissions of nitrous oxide (N2O). The study was conducted on silty loam in a maritime climate in south coastal BC. The slurry was injected in 15-cm deep furrows spaced 75cm apart, or broadcast and quickly incorporated, at 160 kg N ha-1. The corn was planted a few days later at 75 cm spacing, 5-10 cm from the injection furrow. The corn receiving injected manure had about 2 t ha-1 higher yield and 20 kg ha-1 greater N uptake than corn with broadcast manure. However, annual N2O emission was 1.7% of applied N for injected manure compared to 0.5% for broadcast slurry. Emissions of N2O for all treatments spiked sharply shortly after the manure was applied with very low rates observed the rest of the year. Hence the loss of N2O early in the season, likely from denitrification, was not associated with reduced efficiency of N use by the corn. This suggests that N lost by denitrification in the injection treatment was less than N lost by ammonia volatilization from the broadcast manure. Techniques to abate N2O emissions are needed for injected manure.
See more from this Division: ASA Section: Environmental QualitySee more from this Session: Nitrogen-Use Efficiency and Nitrous Oxide Emissions.