Contrasting effects of biochar application rate in an alkaline desert cropland soil

Shelby R. Hoglund; Samuel J. Rathke; Rivka B. Fidel; Joseph C. Blankinship

doi:10.1016/j.jaridenv.2023.105011

Contrasting effects of biochar application rate in an alkaline desert cropland soil

Shelby R. Hoglund, Samuel J. Rathke, Rivka B. Fidel, Joseph C. Blankinship

Environmental Science, Research

Research output: Contribution to journal › Article › peer-review

Abstract

Improving water and nutrient retention in desert croplands using soil organic amendments can be a major challenge because organic matter decomposes quickly under irrigated conditions in a hot climate. Biochar—a long-lasting carbon-rich soil organic amendment—has been proposed to improve soil water and nutrient retention, but only by carefully selecting an appropriate application rate. To better understand effects of biochar application rate on soil water and nutrient retention in desert croplands, we set up a mesocosm-scale experiment with biochar added at rates of 0, 19.8, 39.7, 79.4, 119.0, and 158.7 t ha⁻¹ to an alkaline, sandy loam soil. After initial water retention measurements, we added fertilizer and then measured gaseous nitrogen losses as well as soil nitrate (NO₃⁻) and phosphate (PO₄³⁻) leaching. Then, we measured biochar's effect on the soil's capacity to hold plant-available water (i.e., available water capacity, or AWC) using Tempe cells and a dewpoint potentiometer. We found contrasting effects of low and high biochar application rates. First, we found that applying a minimum of 79.4 t ha⁻¹ biochar was necessary to improve soil water and PO₄³⁻ retention; application rates below 79.4 t ha⁻¹ exacerbated PO₄³⁻ leaching whereas treatments above 79.4 t ha⁻¹ improved AWC by up to 34% compared to the control treatment. While biochar application rate did not affect soil nitric oxide or ammonia emissions, we did find that low biochar application rates increased soil nitrous oxide emission while higher application rates reduced emission compared to soil with no biochar. Overall, we found that lower and higher rates of biochar application can have contrasting effects on soil water and nutrient retention in an alkaline, desert cropland soil. Therefore, farmers and other land managers must consider potential drawbacks of lower application rates and threshold responses of higher application rates prior to large-scale biochar use in arid agroecosystems.

Original language	English (US)
Article number	105011
Journal	Journal of Arid Environments
Volume	215
DOIs	https://doi.org/10.1016/j.jaridenv.2023.105011
State	Published - Aug 2023

Keywords

Biochar
Gaseous flux
Nitrate
Nutrient leaching
Phosphate
Water retention

ASJC Scopus subject areas

Ecology, Evolution, Behavior and Systematics
Ecology
Earth-Surface Processes

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10.1016/j.jaridenv.2023.105011

Cite this

@article{e6df2987a5e541d6b6b34fdc458c8723,

title = "Contrasting effects of biochar application rate in an alkaline desert cropland soil",

abstract = "Improving water and nutrient retention in desert croplands using soil organic amendments can be a major challenge because organic matter decomposes quickly under irrigated conditions in a hot climate. Biochar—a long-lasting carbon-rich soil organic amendment—has been proposed to improve soil water and nutrient retention, but only by carefully selecting an appropriate application rate. To better understand effects of biochar application rate on soil water and nutrient retention in desert croplands, we set up a mesocosm-scale experiment with biochar added at rates of 0, 19.8, 39.7, 79.4, 119.0, and 158.7 t ha−1 to an alkaline, sandy loam soil. After initial water retention measurements, we added fertilizer and then measured gaseous nitrogen losses as well as soil nitrate (NO3−) and phosphate (PO₄³⁻) leaching. Then, we measured biochar's effect on the soil's capacity to hold plant-available water (i.e., available water capacity, or AWC) using Tempe cells and a dewpoint potentiometer. We found contrasting effects of low and high biochar application rates. First, we found that applying a minimum of 79.4 t ha−1 biochar was necessary to improve soil water and PO₄³⁻ retention; application rates below 79.4 t ha−1 exacerbated PO₄³⁻ leaching whereas treatments above 79.4 t ha−1 improved AWC by up to 34% compared to the control treatment. While biochar application rate did not affect soil nitric oxide or ammonia emissions, we did find that low biochar application rates increased soil nitrous oxide emission while higher application rates reduced emission compared to soil with no biochar. Overall, we found that lower and higher rates of biochar application can have contrasting effects on soil water and nutrient retention in an alkaline, desert cropland soil. Therefore, farmers and other land managers must consider potential drawbacks of lower application rates and threshold responses of higher application rates prior to large-scale biochar use in arid agroecosystems.",

keywords = "Biochar, Gaseous flux, Nitrate, Nutrient leaching, Phosphate, Water retention",

author = "Hoglund, {Shelby R.} and Rathke, {Samuel J.} and Fidel, {Rivka B.} and Blankinship, {Joseph C.}",

note = "Funding Information: Interestingly, we found that plant-available water capacity (AWC) did not increase until biochar application rate exceeded 79.4 t ha−1, whereas gravimetric soil water-holding capacity increased proportionally with increasing biochar application rate. Although at low application rates, biochar did not increase AWC, the large error bars in Fig. 1 indicate that 79.4 t ha−1 biochar is a threshold rate at which AWC begins to increase. While biochar itself contains nano- and micro-sized pores, higher biochar application rates likely provide a sufficient amount of smaller biochar particles to fill macropore space in sandy loam soil. This is because an application of biochar used in our study provided a distribution of particle sizes that includes large biochar particles (1/4″ minus) that rearrange soil particles when mixed and smaller biochar particles that fill macropore space and slow or stop the downward movement of water (Villagra-Mendoza and Horn, 2018). Studies using smaller biochar particle size found increased AWC even at low biochar application rates (Hansen et al., 2016; Pudasaini et al., 2016). Our findings support that application rates of biochar with particles as large as 1/4” need to be greater than 30 t ha−1 in coarse-textured soils to have a statistically significant effect on AWC (Edeh et al., 2020). It is crucial to identify thresholds like these prior to field-scale applications so that adding biochar actually improves soil water retention and reduces irrigation water requirements in croplands.We gratefully acknowledge financial support from the Foundation for Food and Agriculture Research (FFAR) Fellows program (ffarfellows.org) and the University of Arizona College of Agriculture and Life Sciences (CALS) Innovation Venture Investment Program (iViP). We thank the University of Arizona Campus Agricultural Center for providing the facility for our study. We thank Bradley Schlottman, Breanna Clabourne, and Anthony Bacinski for assistance with greenhouse measurements. We thank Mohammad Gohardoust, Dr. Markus Tuller, and Dr. Marcel Schaap for help with Tempe Cell Measurements. We thank Dr. Kirsten Ball for assistance with statistical analysis. Funding Information: We gratefully acknowledge financial support from the Foundation for Food and Agriculture Research (FFAR) Fellows program ( ffarfellows.org ) and the University of Arizona College of Agriculture and Life Sciences (CALS) Innovation Venture Investment Program (iViP). We thank the University of Arizona Campus Agricultural Center for providing the facility for our study. We thank Bradley Schlottman, Breanna Clabourne, and Anthony Bacinski for assistance with greenhouse measurements. We thank Mohammad Gohardoust, Dr. Markus Tuller, and Dr. Marcel Schaap for help with Tempe Cell Measurements. We thank Dr. Kirsten Ball for assistance with statistical analysis. Publisher Copyright: {\textcopyright} 2023 Elsevier Ltd",

year = "2023",

month = aug,

doi = "10.1016/j.jaridenv.2023.105011",

language = "English (US)",

volume = "215",

journal = "Journal of Arid Environments",

issn = "0140-1963",

publisher = "Academic Press Inc.",

}

TY - JOUR

T1 - Contrasting effects of biochar application rate in an alkaline desert cropland soil

AU - Hoglund, Shelby R.

AU - Rathke, Samuel J.

AU - Fidel, Rivka B.

AU - Blankinship, Joseph C.

N1 - Funding Information: Interestingly, we found that plant-available water capacity (AWC) did not increase until biochar application rate exceeded 79.4 t ha−1, whereas gravimetric soil water-holding capacity increased proportionally with increasing biochar application rate. Although at low application rates, biochar did not increase AWC, the large error bars in Fig. 1 indicate that 79.4 t ha−1 biochar is a threshold rate at which AWC begins to increase. While biochar itself contains nano- and micro-sized pores, higher biochar application rates likely provide a sufficient amount of smaller biochar particles to fill macropore space in sandy loam soil. This is because an application of biochar used in our study provided a distribution of particle sizes that includes large biochar particles (1/4″ minus) that rearrange soil particles when mixed and smaller biochar particles that fill macropore space and slow or stop the downward movement of water (Villagra-Mendoza and Horn, 2018). Studies using smaller biochar particle size found increased AWC even at low biochar application rates (Hansen et al., 2016; Pudasaini et al., 2016). Our findings support that application rates of biochar with particles as large as 1/4” need to be greater than 30 t ha−1 in coarse-textured soils to have a statistically significant effect on AWC (Edeh et al., 2020). It is crucial to identify thresholds like these prior to field-scale applications so that adding biochar actually improves soil water retention and reduces irrigation water requirements in croplands.We gratefully acknowledge financial support from the Foundation for Food and Agriculture Research (FFAR) Fellows program (ffarfellows.org) and the University of Arizona College of Agriculture and Life Sciences (CALS) Innovation Venture Investment Program (iViP). We thank the University of Arizona Campus Agricultural Center for providing the facility for our study. We thank Bradley Schlottman, Breanna Clabourne, and Anthony Bacinski for assistance with greenhouse measurements. We thank Mohammad Gohardoust, Dr. Markus Tuller, and Dr. Marcel Schaap for help with Tempe Cell Measurements. We thank Dr. Kirsten Ball for assistance with statistical analysis. Funding Information: We gratefully acknowledge financial support from the Foundation for Food and Agriculture Research (FFAR) Fellows program ( ffarfellows.org ) and the University of Arizona College of Agriculture and Life Sciences (CALS) Innovation Venture Investment Program (iViP). We thank the University of Arizona Campus Agricultural Center for providing the facility for our study. We thank Bradley Schlottman, Breanna Clabourne, and Anthony Bacinski for assistance with greenhouse measurements. We thank Mohammad Gohardoust, Dr. Markus Tuller, and Dr. Marcel Schaap for help with Tempe Cell Measurements. We thank Dr. Kirsten Ball for assistance with statistical analysis. Publisher Copyright: © 2023 Elsevier Ltd

PY - 2023/8

Y1 - 2023/8

N2 - Improving water and nutrient retention in desert croplands using soil organic amendments can be a major challenge because organic matter decomposes quickly under irrigated conditions in a hot climate. Biochar—a long-lasting carbon-rich soil organic amendment—has been proposed to improve soil water and nutrient retention, but only by carefully selecting an appropriate application rate. To better understand effects of biochar application rate on soil water and nutrient retention in desert croplands, we set up a mesocosm-scale experiment with biochar added at rates of 0, 19.8, 39.7, 79.4, 119.0, and 158.7 t ha−1 to an alkaline, sandy loam soil. After initial water retention measurements, we added fertilizer and then measured gaseous nitrogen losses as well as soil nitrate (NO3−) and phosphate (PO₄³⁻) leaching. Then, we measured biochar's effect on the soil's capacity to hold plant-available water (i.e., available water capacity, or AWC) using Tempe cells and a dewpoint potentiometer. We found contrasting effects of low and high biochar application rates. First, we found that applying a minimum of 79.4 t ha−1 biochar was necessary to improve soil water and PO₄³⁻ retention; application rates below 79.4 t ha−1 exacerbated PO₄³⁻ leaching whereas treatments above 79.4 t ha−1 improved AWC by up to 34% compared to the control treatment. While biochar application rate did not affect soil nitric oxide or ammonia emissions, we did find that low biochar application rates increased soil nitrous oxide emission while higher application rates reduced emission compared to soil with no biochar. Overall, we found that lower and higher rates of biochar application can have contrasting effects on soil water and nutrient retention in an alkaline, desert cropland soil. Therefore, farmers and other land managers must consider potential drawbacks of lower application rates and threshold responses of higher application rates prior to large-scale biochar use in arid agroecosystems.

AB - Improving water and nutrient retention in desert croplands using soil organic amendments can be a major challenge because organic matter decomposes quickly under irrigated conditions in a hot climate. Biochar—a long-lasting carbon-rich soil organic amendment—has been proposed to improve soil water and nutrient retention, but only by carefully selecting an appropriate application rate. To better understand effects of biochar application rate on soil water and nutrient retention in desert croplands, we set up a mesocosm-scale experiment with biochar added at rates of 0, 19.8, 39.7, 79.4, 119.0, and 158.7 t ha−1 to an alkaline, sandy loam soil. After initial water retention measurements, we added fertilizer and then measured gaseous nitrogen losses as well as soil nitrate (NO3−) and phosphate (PO₄³⁻) leaching. Then, we measured biochar's effect on the soil's capacity to hold plant-available water (i.e., available water capacity, or AWC) using Tempe cells and a dewpoint potentiometer. We found contrasting effects of low and high biochar application rates. First, we found that applying a minimum of 79.4 t ha−1 biochar was necessary to improve soil water and PO₄³⁻ retention; application rates below 79.4 t ha−1 exacerbated PO₄³⁻ leaching whereas treatments above 79.4 t ha−1 improved AWC by up to 34% compared to the control treatment. While biochar application rate did not affect soil nitric oxide or ammonia emissions, we did find that low biochar application rates increased soil nitrous oxide emission while higher application rates reduced emission compared to soil with no biochar. Overall, we found that lower and higher rates of biochar application can have contrasting effects on soil water and nutrient retention in an alkaline, desert cropland soil. Therefore, farmers and other land managers must consider potential drawbacks of lower application rates and threshold responses of higher application rates prior to large-scale biochar use in arid agroecosystems.

KW - Biochar

KW - Gaseous flux

KW - Nitrate

KW - Nutrient leaching

KW - Phosphate

KW - Water retention

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DO - 10.1016/j.jaridenv.2023.105011

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JO - Journal of Arid Environments

JF - Journal of Arid Environments

M1 - 105011

ER -

Contrasting effects of biochar application rate in an alkaline desert cropland soil

Abstract

Keywords

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