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United States Department of Agriculture

Agricultural Research Service

Research Project: SOIL CONSERVATION SYSTEMS FOR SUSTAINABILITY OF PACIFIC NORTHWEST AGRICULTURE Title: Predicting agricultural management influence on long-term soil organic carbon dynamics: implications for biofuel production

Authors
item Gollany, Hero
item Rickman, Ron -
item Liang, Yi -
item Albrecht, Stephan -
item Machado, Stephen -
item Kang, Shujiang -

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 9, 2010
Publication Date: December 9, 2010
Citation: Gollany, H.T., Rickman, R.W., Liang, Y., Albrecht, S., Machado, S., Kang, S. 2010. Predicting agricultural management influence on long-term soil organic carbon dynamics: implications for biofuel production. Agron. J. 103:234-246. doi:10.2134/agronj2010.0203s

Interpretive Summary: Long-term field experiments are ideal for predicting the influence of agricultural management on soil organic carbon dynamics and examining biofuel crop residue removal policy questions. We simulated soil organic carbon dynamics in long-term field experiments under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model (a process-based carbon balance model), and predicted the potential of no-tillage management to maintain soil organic carbon stocks in various soils while removing crop residue. We used the classical long-term experiments at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) because of their documented history of management practice and periodic soil organic matter measurements. Management practices in these experiments ranged from monoculture to two or three year crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned or harvested. Measured and CQESTR predicted soil organic carbon stocks corresponded well under diverse agronomic practices, mean annual temperature (35.8 – 66.2 °F), precipitation (15.8 – 38.3”), and soil organic carbon (0.59 –3.36%) at the sites. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing soil organic carbon stocks were influenced by initial soil organic carbon stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under no-tillage are options to mitigate loss of crop residue carbon from agricultural soils, as using fertilizer alone is insufficient to overcome residue removal impact on soil organic carbon stocks.

Technical Abstract: Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model, and (ii) to predict the potential of no-tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to two or three year crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1-19 °C), precipitation (402 - 973 mm), and SOC (5.89 -33.58 g SOC kg-1) at the LTE sites were significantly related (r2 = 0.94, n=186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks. [GRACEnet and REAP publication].

Last Modified: 12/22/2014
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