Author ORCID Identifier

https://orcid.org/0009-0008-5142-0490

Date Available

4-21-2023

Year of Publication

2023

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department/School/Program

Plant and Soil Sciences

First Advisor

Dr. Frank J. Sikora

Second Advisor

Dr. Edwin L. Ritchey

Abstract

Poultry litter (PL) is traditionally applied to no-till maize (Zea mays L.) cropping systems by surface broadcast. Poultry litter is nutrient dense, and it has been repeatedly shown that surface applied PL nitrogen (N) is vulnerable to losses to the atmosphere and nearby water systems. An application method was developed by USDA-Agricultural Research Service scientists for banding poultry litter (PL) below the soil surface with minimal soil disturbance to reduce ammonia (NH3) volatilization and surface run-off. It is well documented that subsurface applied poultry litter (PL) reduces N losses by ammonia (NH3) volatilization; however, the effect of this application method on N2O emissions and crop yields have been mixed. Nitrogen fertilization of agricultural soil stimulates nitrous oxide (N2O) production, a potent greenhouse gas, and accounts for over 75% of the anthropogenic N2O emissions globally. Best management practices for land application of animal manures as a source of N don’t primarily address the effect they have on N2O emissions. A two-year field experiment was initiated May 2014 on a Crider silt loam to determine if subsurface applying PL in multiple bands between maize (Zea mays L.) rows influenced N2O emissions, NH3 volatilization, nutrient use, and maize yield. Treatments consisted of an untreated control (UTC), urea ammonium nitrate (UAN, 32% N) surface banded (Fert), PL surface broadcast (PLBr), and three subsurface banded PL treatments. The subsurface PL treatments were 1 (PLSub1), 2 (PLSub2), and 3 (PLSub3) lateral bands in the inter-maize row area. Treatments receiving N amendments were added at 180 kg total N ha-1 each spring prior to maize planting. Nitrous oxide emission varied each growing season and N2O pulses coincided with rainfall events larger than 1-cm following treatment application. Subsurface banding PL had significantly lower (P < 0.1) cumulative N2O emissions than PLBr in 2014 and 2015 in at least some treatments. Surface broadcasting PL had greater NH3 volatilization than all PLSub treatments, which agrees with other studies. There were no differences between PLSub treatments in 2014 and 2015 for cumulative N2O emissions and NH3 volatilization. Nitrogen concentration in V4 maize aboveground dry matter was significantly higher in PLSub1 than PLSub2. Aboveground biomass yields for all PLSub treatments were greater than PLBr and similar to Fert. Subsurface PL application in 1 and 2 bands resulted in maize grain yields similar to Fert and significantly greater than PLBr and UTC when averaged across years. Few significant differences were observed in post-harvest soil sample nutrient concentrations between PLSub treatments. These results suggested that subsurface banding PL can reduce N2O emissions, conserve N, and increase no-till maize yields compared to the traditional method of surface broadcasting PL. Increasing the frequency of subsurface PL bands between maize rows did not clearly affect N2O emissions, nutrient conservation, or nutrient utilization by maize across the growing season.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2023.065

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