Location: Grain Quality and Structure Research
Project Number: 3020-43440-002-009-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2018
End Date: Aug 31, 2023
Objective:
The objective is to evaluate how a Plains cropping system impacts sustainable production and quality of grain sorghum by measuring greenhouse gases/carbon sequestration of sorghum grown in Oklahoma under different crop rotation/production schemes.
Approach:
An experiment will be located at the Oklahoma Panhandle Research and Extension Center at Goodwell, OK on a gruver clay loam. This preliminary study will include 2 treatments with 4 replicates with one treatment being a control treatment which receives only starter fertilizer at a rate of 5 gals/acre of 10-34-0. The second treatment will receive 50 lbs of N/acre at 32-0-0 solution applied with streamer nozzles near planting prior to expected rainfall (we might inject this if rainfall chances are low, we have a no-till liquid injection unit at that station). These plots will be established in a field under standard rotation of grain sorghum fallow wheat fallow such that the grain sorghum will be planted into wheat stubble from the 2017 wheat harvest.
N2O emission will be measured by a vented chamber technique. Chambers will be installed directly after fertilization and emissions will be measure daily for 1 week followed by weekly measurements. At planting the chambers will be removed and then reinstalled.
Emissions measurements are achieved by placing the chamber lid on the chamber and immediately collecting the time zero headspace sample. Three additional headspace samples are collected on 15 min increments. These samples are stored at stable temperature and overnight shipped to Stillwater, for analysis using a gas chromatograph. The resulting headspace concentrations are regressed against time and the resulting slope is used to calculate the N2O flux during that measurement event. Linear extrapolation is used to estimate flux between sampling points and them season emissions are estimated.
The difference between N2O emitted from the control and fertilized treatment will be used to estimate the N2O emission factor per unit of N applied.
Grain yield will also be measured to understand its response to added fertilizer N and the corresponding N emissions. Grain samples will be collected and analyzed for quality to understand the interaction between N2O emission and carbon sequestration potential for this ethanol and feed grain feed stock.
