Biochar has been shown to enhance nutrient retention due to its high cation exchange capacity (CEC) and high surface area. It can perform as a slow release fertilizer by permeating with other nutrients, and therefore increases fertilizer efficiency and increase crop yields. Furthermore, biochar has been shown to mitigate nutrient losses via surface runoff and leaching. The effect of biochar and biochar-compost mixture (poultry manure) application on crop yields and nitrogen losses in surface runoff and sub-surface leachate was studied for four years. The research site was established at the Red River Research Station, Louisiana State University Agricultural Center in Bossier City, LA. The site was shaped for uniform drainage to a 0.2% east-west slope on a Norwood very fine sandy loam (Typic Udifluvent: fine-silty, mixed, calcareous, thermic). The site had 12 plots and 110 m wide by 135 m-long, each divided into 8 rows. The lowest part of each plot drained into a vinyl-lined ditch connected to 0.45 m H-flume established on a concrete pad for water sampling. An automatic refrigerated sampler (ISCO model 3700FR, Lincoln, NE) and a flowmeter (ISCO model 4230, Lincoln, NE) with bubble sensors were installed near the H-flume. The evaluated four treatments were control, poultry manure compost, biochar, and biochar-compost mixture application with the completely randomized design for statistical analysis. Biochar, compost (poultry manure), and biochar-compost mixture were applied to cotton fields (variety: ST5032GLT: Stoneville) in March prior to cotton planting in early May. The two application rates of biochar added to the appropriate plots were 1,541 kg ha-1 and 3,083 kg ha-1 per plot and poultry manure compost applied rate was 1,311 kg ha-1 per plot. The content of organic matter, total nitrogen (N), and cation exchange capacity (CEC) of the compost were 69.7 %, 2.01 %, and 46.2 cmolc kg-1, respectively. The content of carbon and nitrogen in biochar were 29% and 3.48%, respectively. Surface runoff was collected with automatic refrigerated samplers, and sub-surface leachate was collected with slim tube lysimeters over a period of four years. The mean losses of nitrogen (TN, NO3/NO2-N, and NH4-N) via runoff and leaching from different treatments will be presented. Additionally, the influence of biochar application on cotton yields from the different treatments will be compared and reported at the conference.

Impact of biochar and biochar-compost mixture application on cotton yield and nutrient runoff losses in four consecutive planting seasons

255th National Meeting (2018)

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