|ALLER, DEBORAH - Iowa State University
|RATHKE, SAMUEL - Iowa State University
|LAIRD, DAVID - Iowa State University
|CRUSE, RICHARD - Iowa State University
Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2017
Publication Date: 8/11/2017
Publication URL: https://handle.nal.usda.gov/10113/5809198
Citation: Aller, D., Rathke, S., Laird, D., Cruse, R., Hatfield, J.L. 2017. Impacts of fresh and aged biochars on plant available water and water use efficiency. Geoderma. 302:114-121. https://doi.org/10.1016/j.geoderma.2017.08.007.
Interpretive Summary: Soil water availability is critical for plant growth and enhancing the ability of the soil to absorb and store more water could offer potential solutions in areas with increasing variability in rainfall. To understand the potential for changing soil water availability a study was conducted in a greenhouse on corn to evaluate how different biochar materials would affect the availability of soil water to corn. This study showed that adding these materials decreased the availability of water to the plant and that there were differences among soils. The inconsistency in the response to biochar suggests that caution is needed to interpret the impacts of soil amendments on water in the soil. These results will be of value to scientists and consultants who have questions about the role of biochar in soils.
Technical Abstract: The ability of soils to hold sufficient plant available water (PAW) between rainfall events is critical to crop productivity. Most studies indicate that biochar amendments decrease soil bulk density and increase soil water retention. However, limited knowledge exists regarding biochars ability to influence PAW and water use efficiency (WUE), and even less is known about the effects of aged biochars on PAW and WUE. This greenhouse study investigated the influence of six fresh and six aged biochars on PAW and WUE for three soils of contrasting texture. PAW and WUE were assessed by growing maize in repacked soil columns (1 kg soil). Plant and water data were collected from the V1 growth stage until the plants died of water stress. Relative to the controls, both fresh and aged biochars increased soil moisture retention in the clay loam soil, had no impact in a silt loam soil, and had variable effects in a sandy loam soil. Final biomass weight increased with the addition of fresh biochar in the sandy loam and silt loam soils and decreased in the clay loam soil, while aged biochar increased biomass weight in the silt loam soil. Both fresh and aged biochars decreased PAW in the clay loam soil and had no impact on PAW in the silt loam soil. Fresh biochar increased PAW, while aged biochar had no effect on PAW for the sandy loam soil. WUE decreased in response to both fresh and aged biochars in the clay loam soil and was variable for the other two soils. Results of this experiment indicate that biochar type and biochar age have variable impacts on PAW and WUE, indicating that biochar amendments can improve soil water relations and crop growth under water limited conditions for some but not all soils.