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Does No‐Tillage Mitigate Stover Removal in Irrigated Continuous Corn? A Multi‐Location Assessment

Author:
Catherine E. Stewart, Damaris L. Roosendaal, Aaron Sindelar, Elizabeth Pruessner, Virginia L. Jin, Marty R. Schmer
Source:
Soil Science Society of America journal 2019 v.83 no.3 pp. 733-742
ISSN:
0361-5995
Subject:
Zea mays, carbon sequestration, community structure, corn, crop production, irrigation, microbial activity, microbial biomass, no-tillage, phospholipid fatty acids, production technology, soil aggregation, soil microorganisms, soil organic carbon, soil properties, stable isotopes, stover, Colorado, Nebraska
Abstract:
Core Ideas Long‐term residue removal with irrigation may degrade soil despite no‐tillage. Residue removal was assessed across three irrigated corn no‐tillage sites. Stover removal decreased soil organic C stocks by 6% and soil aggregation by 12%. Stover removal did not affect soil microbial biomass or composition. No tillage alone is not adequate to reduce erosion and maintain soil function. No‐tillage (NT) may ameliorate negative effects on soil properties from corn (Zea mays L.) stover harvest, but few long‐term irrigated continuous corn production systems have been evaluated to test this hypothesis. We evaluated three long‐term no‐tillage sites (4–13 yr) in Nebraska and Colorado that spanned a range of precipitation and soil organic carbon (SOC) levels. We measured SOC, δ¹³C of SOC, soil microbial biomass (SMB) and composition (i.e., phospholipid fatty acids, PLFAs), and water stable aggregation at all sites under stover retention vs. removal (∼60%). Surface SOC stocks (0–30‐cm depth) increased across the gradient and were 46.4, 57.4, and 63.1 Mg C ha–¹ for Colorado, central Nebraska, and eastern Nebraska, respectively. Overall, residue removal decreased SOC stocks by 6% and soil aggregation by 12% in the 0‐ to 30‐cm depth. The δ¹³C signature of SOC indicated less new surface C storage under residue removal in Colorado, but not at the two Nebraska sites. Residue harvest did not decrease SMB or change soil microbial community structure, suggesting that high plant productivity buffered community composition from stover harvest impacts under NT but stimulated microbial activity levels that led to SOC loss. The high rates of stover removal used in this study decreased SOC stocks and aggregation at all sites compared to residue retained treatments, suggesting that no‐tillage alone was not sufficient to maintain erosion protection and soil function.
Agid:
6612026
Handle:
10113/6612026