Alternative N fertilizers that produce low greenhouse gas (GHG) emissions from soil are needed to reduce the impacts of agricultural practices on global warming potential (GWP). We quantified and compared growing season fluxes of NO, CH, and CO resulting from applications of different N fertilizer sources, urea (U), urea-ammonium nitrate (UAN), ammonium nitrate (NHNO), poultry litter, and commercially available, enhanced-efficiency N fertilizers as follows: polymer-coated urea (ESN), SuperU, UAN + AgrotainPlus, and poultry litter + AgrotainPlus in a no-till corn ( L.) production system. Greenhouse gas fluxes were measured during two growing seasons using static, vented chambers. The ESN delayed the NO flux peak by 3 to 4 wk compared with other N sources. No significant differences were observed in NO emissions among the enhanced-efficiency and traditional inorganic N sources, except for ESN in 2009. Cumulative growing season NO emission from poultry litter was significantly greater than from inorganic N sources. The NO loss (2-yr average) as a percentage of N applied ranged from 0.69% for SuperU to 4.5% for poultry litter. The CH-C and CO-C emissions were impacted by environmental factors, such as temperature and moisture, more than the N source. There was no significant difference in corn yield among all N sources in both years. Site specifics and climate conditions may be responsible for the differences among the results of this study and some of the previously published studies. Our results demonstrate that N fertilizer source and climate conditions need consideration when selecting N sources to reduce GHG emissions.

Nitrogen is one of the most important and costly nutrient inputs for crop production. Farmers are looking for better management practice to enhance production and reduce environmental impact. A 3‐yr field study was established to examine corn (Zea mays L.) grain yield and nutrient uptake resulting from application of 168 kg N ha−1 as urea (U), urea‐ammonium nitrate (UAN), ammonium nitrate (NH4NO3), poultry litter (PL), and similar rate of commercially available enhanced‐efficiency nitrogen fertilizers (EENF) as follow: polymer‐coated urea (ESN), SuperU, UAN + AgrotainPlus, and PL + AgrotainPlus in a no‐till corn production. Treatments were replicated four times in a completely randomized block design from 2009 to 2011. Aboveground plant biomass was harvested at physiological maturity each year to determine dry matter and nutrient uptake. Soil samples were taken three times per year to evaluate the status of the selected nutrients in soil. There was a significant increase in corn aboveground dry matter and grain yield with application of 168 kg N ha−1 compared with control treatment. There was no significant difference in corn grain yield or dry matter among the N sources. However, averaged across all N sources, corn grain yield (10.1 Mg ha−1) in 2009 was greater than grain yield (7.5 Mg ha−1) in 2010 and 2011, mainly due to higher rainfall and better distribution in 2009. Addition of AgrotainPlus to UAN and PL did not influence corn grain yield. Additional research is needed to evaluate EENFs under different climatic conditions and different management practices.

Biochar holds promise as a soil amendment with potential to sequester carbon, improve soil fertility, adsorb organic pollutants, stimulate soil microbial activities, and improve crop yield. We used a hardwood biochar to assess its impact on corn (Zea mays) grain, biomass yields and greenhouse gas emission in central Kentucky, USA. Six treatments included as follows: control (C) with no amendment applied; poultry litter (PL); biochar (B); biochar + poultry litter (B + PL); fertilizers N-P-K (F); and biochar + fertilizers (B + F). Biochar was applied only once to plots in 2010 followed by rototilling all plots. Only PL and fertilizer were applied annually. When applied alone, biochar did not significantly increase dry matter, grain yield, and N-P-K uptake. There was also no significant difference between the combined treatments when compared with PL or F applications alone. We observed a slight increasing trend in corn grain yield in the following 2 years compared to the first year from biochar treatment. Poultry litter treatment produced significantly greater N2O and CO2 emissions, but emissions were lower from the B+PL treatment. We conclude that this biochar did not improve corn productivity in the short term but has potential to increase yield in the long term and may have some benefit when combined with PL or F in reducing N2O and CO2 emissions.

Adopting efficient management practices for using poultry litter (PL) as an alternative to commercial fertilizer is critical for increased N use efficiency. This 3-year study investigated effects of application time (fall and spring) and method of application (soil incorporation and nonincorporation) of three PL rates and NH 4 NO 3 (146 kg N ha j1 ) on availability of selected soil nutrients and corn (Zea mays L.) grain yield in northern Alabama. The plant-available N rates supplied by the PL were 68 kg N ha j1 (low), 135 kg N ha j1 (medium), and 270 kg N ha j1 (high). Soil inorganic N, Mehlich3Yextractable P, and available K were measured before planting in April, mid-season in June or July, and postharvest in October or November. Averaged across the 3 years, grain yield from the high PL rate was similar to that of the medium PL rate when spring applied. The medium PL rate resulted in 800 kg ha j1 greater grain yield than NH 4 NO 3 from both spring and fall applications. Incorporation of the medium PL rate increased grain yield 590 kg ha j1 and NH 4 NO 3 by 480 kg ha j1 , respectively, than nonincorporation but no yield advantage of incorporating the low and high PL rates. Inorganic N, Mehlich-3Yextractable P, and available K were highest from midseason sampling and from spring than fall applications. When N sources were incorporated, the medium PL rate resulted in greater N and P uptake. Results from this study suggest that fall application of NH 4 NO 3 and PL beyond the medium rate should not be encouraged for warm climatic conditions.

Nitrogen fertilizer management is vital to corn (Zea mays L.) production from financial and environmental perspectives. Poultry litter as a nutrient source in this cropping system is generally surface broadcast, potentially causing volatilization of NH3. Recently a new application method was developed allowing subsurface banding of poultry litter with minimal soil surface disturbance. However, there are limited data with this application method on corn production. In this study, we used farm‐scale plots (7.6 by 91.2 m) to evaluate the response of no‐till corn growth and post‐harvest soil nutrient concentrations from subsurface poultry litter application. All treatments were applied pre‐plant at a rate of 168 kg N ha−1 and included (i) a standard commercial fertilizer surface broadcast, (ii) poultry litter surface applied, and (iii) poultry litter applied in subsurface bands placed 30 cm apart and 8‐cm deep below the soil surface. Results showed that poultry litter subsurface banded plots resulted in corn grain and above ground biomass yields similar to plots treated with commercial fertilizer. In 2011, corn grain yield of 11.35 Mg ha−1 produced by the subsurface banded poultry litter treatment was significantly higher when compared to surface applied poultry litter that yielded 10.10 Mg ha−1. Poultry litter application method did not have a significant effect on post‐harvest soil pH, total C, total N, NH4+‐N, NO3−–N, P, and K concentrations. Results from this study suggest that subsurface banding of poultry litter can be utilized as an alternate application method in no‐till corn without detrimental impacts on productivity.Core Ideas Foremost study examining subsurface banding of poultry litter on corn production. Subsurface banded poultry litter had 8.75% greater corn yield than surface applied. Subsurface band poultry litter increased N availability by 3.8% over surface applied.