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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #72056
Title: TILLAGE AND CROP ROTATION EFFECTS ON SUBSURFACE DRAINAGE RESPONSE TO RAINFALL

Author
item Bjorneberg, David - Dave
item KANWAR, R
item MELVIN, S

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Subsurface drain flow rates can increase rapidly due to rain storms. Rapid changes are often attributed to water flowing preferentially through cracks or root and worm holes in the soil. Crops and tillage can alter these preferential flow paths. At a field study on Iowa State University's Northeast Research Farm however, tillage and crops had little impact on water flow to subsurface drains after rain storms during the 1993 and 1994 growing seasons. By the third year of the study, some parameters indicated that drain flow from no-till plots changed faster than chisel plow plots. Differences in the volume and rate of water flow in subsurface drains were inconsistent between corn and soybean crops under no-till and chisel plow tillage treatments. Overall results of the three-year study showed that soil characteristics had a larger impact on water flow to subsurface drains than crops or tillage. Differences between crop and tillage treatments may be more consistent over a longer study period as treatments become better established.

Technical Abstract: A field study was conducted to determine if tillage and crop rotation affected subsurface drainage response to rainfall. An instrumentation system collected subsurface drain flow data from thirty-six, 0.4 ha plots during the 1993, 1994, and 1995 growing seasons. Response time, time-to-peak drain flow rate, drainage volume, peak drain flow rate, and percent preferential flow were compared between two tillage systems (no- till and chisel plow) and two crop rotations (continuous corn and corn- soybean) for 18 drainage events over the three-year study. The influence of preferential flow was estimated for each drainage event using a hydrograph separation procedure based on subsurface drain flow rate changes. Drainage event parameters were not consistently different between crop and tillage systems during this study. Drainage parameter data were highly variable and little correlation was observed between parameters. Percent preferential flow was found to be greater than 10% of the total subsurface drain flow only four times for the 18 drainage events. The highest average percent preferential flows for an event did not correlate with the highest rainfall intensity and varied among crop and tillage systems. Drainage event parameters indicated more preferential flow from no-till compared to chisel plow only in 1995. Overall results indicated that changes occurring in the soil flow system during the growing season may have more influence on preferential flow and subsurface drain flow compared to tillage and crop rotations for these loam soils.