Biochar-Swine Manure Impact on Soil Nutrients and Carbon Under Controlled Leaching Experiment Using a Midwestern Mollisols

Abstract

Biochar application to the soil can improve soil quality and nutrient leaching loss from swine manure adapted soils. Our working hypothesis was that the biochar-incubated with manure could be a better soil amendment than conventional manure application. The manure-biochar application to the soil would decrease nutrient leaching from manure and increase plant-available nutrients. The study objectives were to 1) assess the physicochemical properties of the manure-biochar mixture after lab incubation and 2) evaluate the impact of biochar-treated swine manure on soil total C, N, and other major and minor nutrients in comparison to conventional manure application to soil. Three biochars 1) neutral pH red-oak (RO), 2) highly alkaline autothermal corn (Zea mays) stover (HAP), and 3) mild acidic Fe-treated autothermal corn stover (HAPE) were incubated with swine manure for a month. The biochar-manure mixture was applied in triplicate to soil columns with an application rate determined by the P2O5-P content in manure or manure-biochar mixtures after the incubation. The ammonium (NH4+), nitrate (NO3‒), and reactive P concentrations in soil column leachates were recorded for eight leaching events. Soil properties and plant-available nutrients were compared between treatments and control manure and soil. Manure-(HAP&HAPE) biochar treatments significantly increased soil organic matter (OM), and all biochar-manure mixture increased (numerically) soil total C, N, and improved soil bulk density. Concentrations of NH4+ and NO3‒ significantly increased in MHAPE column leachates during this 4-week study and the KCl-extractable NH4+ and NO3‒ in the soil at the end of the experiment. A significant reduction in soil Mehlich3 Cu was also observed for the manure-HAPE mixture compared with the manure control. The manure-red oak biochar significantly increased the soil Mn availability than other manure-biochar treatments or manure control. Overall, the manure-biochar incubation enabled biochar to stabilize the C and several nutrients from manure. The subsequent manure-biochar mixture application to soil improved soil quality and plant nutrient availability compared to conventional manure application. This proof-of-the-concept study suggests that biochars could be used to solve both environmental and agronomic challenges and further improve the sustainability of animal and crop production agriculture.

Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure During 3-hour Agitation Using Pelletized Biochar

“…Results comparing the changes in manure properties confirmed that acidic biochar could mitigate NH3 emissions and likely prevent nitrogen loss in the manure. Manure treated with biochar powder showed benefits to soil health, lowered nutrient runoff risk, and the potential for agronomic benefits to corn and soybeans (Banik et al, 2021a(Banik et al, , 2021b shown on lab and greenhouse scales. In addition, more techno-economic analyses are warranted on the potential savings due to the nutrient retention in manure, as the average cost of anhydrous ammonia is $526/ton (USDA, 2021).…”

“…Biobased-fuels production, waste-to-carbon, and waste-to-energy thermal processes result in a relatively low-value biocoal. Circular economy opportunities exist for the valorization of biochar and the improvement of sustainability in animal and crop production systems (Banik et al, 2021a;Banik et al, 2021b). The long-term goal is to test and scale up the treatments from laboratory-scale to farm-scale, keeping in mind the techno-economic constraints for many swine farmers.…”

“…Synergistic effects to biochar use could be achieved for the animalcrop production system. First, biochar can be used to mitigate gaseous emissions from manure, and then the biochar and manure mixture can be used as a better quality fertilizer, improve the soil nutrients content and minimize the nutrient losses from soil (Banik et al, 2021a;Banik et al, 2021b). Therefore, innovative biochar treatment could be a one-stop solution to solve the gaseous emissions challenge and improve agriculture's sustainability.…”

Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure during Three-Hour Agitation Using Pelletized Biochar

“…Biobased-fuel production, waste-to-carbon, and wasteto-energy thermal processes result in a relatively low-value biocoal. Circular economy opportunities exist for the valorization of biochar and the improvement of sustainability in animal and crop production systems [22,23]. The long-term goal is to test and scale up the treatments from the laboratory scale to the farm scale, keeping in mind the techno-economic constraints for many swine farmers.…”

“…Thus, synergistic effects to biochar use could be achieved for the animal-crop production system. First, biochar can be used to mitigate gaseous emissions from manure, and then the biochar and manure mixture can be used as a better-quality fertilizer, improve the soil nutrients content, and minimize the nutrient losses from soil [22,23]. Therefore, innovative biochar treatment could be a one-stop solution to solve the gaseous emissions and improve agriculture's sustainability.…”