1a. Objectives (from AD-416)
Measure the crop production and environmental impacts of using new fertilizer technology.
1b. Approach (from AD-416)
This series of experiments will include a controlled release polymer-coated urea (ESN), stabilized urea sources of SuperU and urea ammonium nitrate (UAN) treated with AgrotainPlus, a cation-stabilized amine (PiNT), conventional sources of UAN and urea, and an unfertilized check. An N source study will be conducted at the Russell E. Larson Agricultural Research Center at Rock Springs, PA to determine gaseous losses. Nitrous oxide gas emissions will be measured throughout the growing season using vented chambers with gas analysis by gas chromatography. Crop yield, soil N content, temperature, soil water, and other data required to determine N use efficiency and interpret the emission results will be collected. In complementary laboratory experiments, ammonia and nitrous oxide emissions will be measured on surface soil samples collected from the field site and incubated in jars under controlled soil moisture conditions. Nitrogen losses in runoff will be measured on runoff boxes packed with soil collected from the University of Maryland Eastern Shore (UMES) experiment station, amended with the seven N fertilizer treatments described above, and subjected to simulated rainfall following the rainfall simulation protocol for indoor soil boxes as developed and described by the National P Project. N losses in the form of ammonium, nitrate and urea will be determined by flow injection analyses. Nitrogen leaching losses from the fertilizer treatments will be measured on soil columns using intact soil cores collected from the University of Maryland Eastern Shore (UMES) experiment station and at Rock Springs, PA on turfgrass plots established on constructed greens equipped with lysimeters.
3. Progress Report
The purported improved nitrogen use efficiency (30% less N application required) of the PiNT technology developed by Plant Impact plc. is being assessed, quantified and reported. Field plots were established in 2010 comparing six nitrogen fertilizer sources, nitrous oxide emissions were measured weekly or twice weekly throughout the growing season, and corn grain yields were compared. Nitrous oxide emissions and grain yield were similar regardless of fertilizer source in 2010. Fertilizers applications were repeated in the spring of 2011 and gas emission measurements are currently being taken. Runoff boxes packed with soil collected from the University of Maryland Eastern Shore (UMES) Research and Teaching Farm and amended with seven N fertilizer and manure treatments were subjected to simulated rainfall. N losses in the form of ammonium, nitrate and urea were determined by flow injection analysis. Data are currently being summarized by a PhD candidate at UMES. Nitrogen leaching losses from fertilizer treatments were measured on intact soil cores collected from UMES, but variable background levels obscured differences among treatments. The study was repeated using columns packed with homogenized soil. Columns were pre-leached to reduce N levels in leachate to a minimum. Results showed that PiNT fertilizer behaved similar to urea in terms of N lost in leachate. However, total N recovery was less than 20% indicating that much of the N was retained in the soil, probably fixed by microbial growth and activity. A second nitrogen rate trial comparing PiNT to a nitrate fertilizer analog on turfgrass was completed. Results showed that PiNT at the 75 percent rate compared favorably to the nitrate fertilizer analog at the 100 percent rate with the added benefit that PiNT amended turf plots did not exhibit salt burn following application. A third trial on turfgrass designed to compare PiNT to other commercial fertilizers under a biweekly application management scheme is underway. A rate study of PiNT on corn that was established during the 2010 growing season showed that PiNT performed similar to UAN fertilizer in terms of yield, but slight differences in forage quality were observed. Progress was monitored by daily communications among ARS and Penn State members of the scientific research team, participation in meetings on an as needed basis, and by email exchange of data and information.