Shane M. Troy , Peadar G. Lawlor, Cornelius J. O’ Flynn, and Mark G. Healy (2014). “The Impact of Biochar Addition on Nutrient Leaching and Soil Properties from Tillage Soil Amended with Pig Manure.” Water, Air, & Soil Pollution online ahead of print. DOI: 10.1007/s11270-014-1900-6.
Abstract: The application of pig manure to a tillage soil can result in pollution of surface and groundwater bodies. Countries in the European Union are required to comply with the Water Framework Directive, which states that all countries should attain at least “good status” surface and ground water quality by 2015. Amendment of soil with biochar has previously been shown to reduce nutrient leaching and improve soil properties. The objectives of this laboratory study were to investigate if the application of two types of biochar at a rate of 18 t ha−1 (a) reduced leaching of carbon (C), nitrogen (N) and phosphorus (P) from a low P Index tillage soil amended with pig manure and (b) affected the soil properties before and after pig manure application. Three treatments were examined as follows: (a) non-amended soil (the study control), (b) soil mixed with biochar from the separated solid fraction of anaerobically digested pig manure, and (c) of soil mixed with biochar from Sitka Spruce. Columns, filled with sieved soil (<2 mm) and biochar (<2 mm), were incubated for 30 weeks at 10 °C and 75 % relative humidity and leached with 160 mL distilled water per week. Pig manure, equivalent to 170 kg N ha−1 and 36 kg P ha−1, was applied to half of the columns in each treatment after 10 weeks of incubation. Amendment with pig manure biochar increased the Morgan’s P content of the soil, while leaching of P and C also increased, indicating the unsuitability of pig manure biochar as an amendment to soils which may be used as pig manure spreadlands. However, the addition of wood biochar increased soil water, C and organic matter contents, while reducing nitrate and organic C leaching. The addition of wood-derived biochar to tillage soil which will receive pig manure may be justifiable, as it reduces nutrient leaching from the soil, sequesters C and may allow for higher application rates of pig manure.
Min Huang, Liu Yang,Huadong Qin, Ligeng Jiang, Yingbin Zou (2014) “Fertilizer nitrogen uptake by rice increased by biochar application.” Biology and Fertility of Soils online ahead of print. DOI: 10.1007/s00374-014-0908-9.
Abstract: This study was conducted to test the hypothesis that biochar application can increase rice yield through improving nitrogen (N) uptake and utilization by rice plants under N application conditions. A pot experiment was done with a hybrid rice cultivar grown on a Fe-leachi-Stagnic Anthrosols with and without biochar application. The N fertilizer used was 15N-labeled urea. Results showed that biochar application resulted in 23–27 % increase in fertilizer N uptake by rice plants and consequently 8–10 % increase in grain yield. The higher fertilizer N uptake under biochar application was associated with a reduced fertilizer N loss. Fertilizer N loss rate was reduced by 9–10 % by applying biochar. We suggest that further studies are needed to assess the short-term and long-term effects of different biochars on N uptake and utilization by rice under field conditions.
S. L. Weyers and K. A. Spokas (2014). “Crop residue decomposition in Minnesota biochar amended plots.” Solid Earth Discussion, 6, 599-617. DOI: 10.5194/sed-6-599-2014.
Abstract: Impacts of biochar application at laboratory scales are routinely studied, but impacts of biochar application on decomposition of crop residues at field scales have not been widely addressed. The priming or hindrance of crop residue decomposition could have a cascading impact on soil processes, particularly those influencing nutrient availability. Our objectives were to evaluate biochar effects on field decomposition of crop residue, using plots that were amended with biochars made from different feedstocks and pyrolysis platforms prior to the start of this study. Litterbags containing wheat straw material were buried below the soil surface in a continuous-corn cropped field in plots that had received one of seven different biochar amendments or a non-charred wood pellet amendment 2.5 yr prior to start of this study. Litterbags were collected over the course of 14 weeks. Microbial biomass was assessed in treatment plots the previous fall. Though first-order decomposition rate constants were positively correlated to microbial biomass, neither parameter was statistically affected by biochar or wood-pellet treatments. The findings indicated only a residual of potentially positive and negative initial impacts of biochars on residue decomposition, which fit in line with established feedstock and pyrolysis influences. Though no significant impacts were observed with field-weathered biochars, effective soil management may yet have to account for repeat applications of biochar.