Location: Sugarcane Research
Project Number: 6052-13210-003-009-I
Project Type: Interagency Reimbursable Agreement
Start Date: Apr 5, 2024
End Date: Aug 31, 2031
Objective:
Contribute to the Inflation Reduction Act Measurement Monitoring Reporting and Verification Action Area 2-Cropland through measurement of cropland methane and nitrous oxide emissions.
Approach:
The SRU will monitor GHG emissions from sugarcane fields amended with biochar and starter fertilizer, and spring fertilizer management options. These practices represent climate-smart alternatives to traditional practices currently employed in the Louisiana sugarcane industry. Little data exist on GHG emissions from Louisiana sugarcane fields, an industry that encompasses over 510,000 acres across 22 parishes in south Louisiana. The bagasse-derived biochar is a locally sourced product. Each field test is 1 acre and was set up as a randomized complete block design with four replications, with biochar application as the main plot and starter fertilizer as the split plot. The biochar application rate is 2.0 tons per acre and starter fertilizer is 45 pounds of 13-13-13 per acre at planting. Plot harvest is conducted using a combine harvester with plot weights measured using a 5-ton dump wagon equipped with load-cells in the axle and tongue. A subsample of cut cane is collected using a billet sampler and is tested for sucrose concentration using the prebreaker-core press method. The product of plot yield (tons per acre) and stalk sucrose concentration (lbs. per ton) is field sucrose yield (lbs. per acre). These tests are managed by traditional sugarcane production practices including knife fertilizer on both sides of each row in mid-April, consisting of 100, 80, and 20 lbs. per acre of nitrogen, potassium, and sulfur, respectively, as UAN32, muriate of potash, and elemental sulfur. Beginning in the spring of 2024, we will install PVC rings into all plots and begin taking static chamber measurements of soil gas to test for nitrous oxide, methane, and carbon dioxide. Measurement frequency will be based on field operation (e.g., fertilizer application) as well as precipitation events. A second set of biochar field tests will be set up similar to above except (1) larger – 2 acres in size; and (2) will be modified to include another split plot level – conventional fertilizer application or coulter fertilizer application. In sugarcane, fertilizer is applied once in the spring once the crop is established. The growing sugarcane crop is off-bar cultivated earlier in the spring for weed control from the edges of the row through the wheel furrow to the adjacent row, leaving the top of the row and the growing sugarcane un-touched. Recently growers have used a coulter fertilizer application technique in sugarcane to deliver the fertilizer directly to the top of the row into the sugarcane crop. This contrasts to conventional application described above. The coulter method also eliminates a tillage event. The method places the fertilizer directly into the growing crop whereas knifing fertilizer on row sides does not, creating a scenario where nutrients may be lost due to less plant uptake. These tests will be planted in 2024 and 2025 with GHG measurements beginning in 2025 and 2026, respectively. The SRU also monitors carbon flux above the sugarcane farm using an eddy covariance tower. Additional measurements include 4-way solar radiation, air temperature and humidity, wind speed and direction, precipitation, and soil moisture and temperature.
