Evaluation of residue management practices on barley residue decomposition

Authors: LOOMIS, GRANT - University Of Idaho; DARI, BISWANATH - University Of Idaho; Rogers, Christopher; SIHI, DEBJANI - Oak Ridge National Laboratory

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2020
Publication Date: 5/13/2020
Citation: Loomis, G., Dari, B., Rogers, C.W., Sihi, D. 2020. Evaluation of residue management practices on barley residue decomposition. PLoS One. 15(5):e0232896. https://doi.org/10.1371/journal.pone.0232896.
DOI: https://doi.org/10.1371/journal.pone.0232896

Interpretive Summary: Optimizing barley (hordeum vulgareL.) production in Idaho and other parts of the Pacific Northwest (PNW) should focus on farm resource management. The effect of post-harvest residue management on barley residue decomposition has not been adequately studied. The objective of this study was to determine the effect of residue placement (surface vs. incorporated), residue size (chopped vs. ground-sieved) and soil type (sand and sandy loam) on barley residue decomposition. A 3-mo laboratory incubation experiment was conducted. Following the study, modeling approach was applied to investigate the how fast residue breakdown would be expected to occur. While it is often assumed that incorporation of residue and grinding can potentially increase the rate of residue breakdown, in the current study we did not see any increase in breakdown from these practices. Future residue decomposition studies under field conditions are warranted to verify these results under natural conditions.

Technical Abstract: Optimizing barley (hordeum vulgare L.) production in Idaho and other parts of the Pacific Northwest (PNW) should focus on farm resource management. The effect of post-harvest residue management on barley residue decomposition has not been adequately studied. Thus, the objective of this study was to determine the effect of residue placement (surface vs. incorporated), residue size (chopped vs. ground-sieved) and soil type (sand and sandy loam) on barley residue decomposition. A 3-mo laboratory incubation experiment was conducted at a temperature of 25 to 30 °C at the Aberdeen Research and Extension Center, Aberdeen, Idaho, USA. Following the study, a Markov-Chain Monte Carlo (MCMC) modeling approach was applied to investigate the first-order decay kinetics of barley residue. An accelerated initial flush of C-mineralization was measured for the sieved (Day 1) compared to chopped (Day 3 to 5) residues for both surface incorporated applications. The highest evolution of CO2-C of 8.3 g kg-1 was observed on Day 1 from the incorporated-sieved application for both soils. The highest and lowest amount of cumulative CO2-C released and percentage residue decomposed over 50-d was observed for surface-chopped (107 g kg-1 and 27%, respectively) and incorporated-sieved (69 g kg-1 and 18%, respectively) residues, respectively. There were no significant differences in C-mineralization from barley residue based on soil type or its interactions (p >0.05). The largest decay constant k of 0.0083 d-1 was calculated for surface-chopped residue where the predicted half-life was 80 d, which did not differ from surface sieved or incorporated chopped. In contrast, incorporated-sieved treatments only resulted in a k of 0.0054 d-1 and would need an additional 48 d to decompose 50% of the residue. Future residue decomposition studies under field conditions are warranted to verify the residue C-mineralization and its impact on residue management.