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Limits

Limits. Dr. Jane Frankenberger, Purdue University Agricultural & Biological Engineering. Four Types of Limits. Unanswered Questions Site Limitations Unclear Benefits to Producers Accountability. Before planting or harvest. After planting. After harvest. 1. Unanswered Questions.

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Limits

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  1. Limits Dr. Jane Frankenberger, Purdue University Agricultural & Biological Engineering

  2. Four Types of Limits • Unanswered Questions • Site Limitations • Unclear Benefits to Producers • Accountability Before planting or harvest After planting After harvest

  3. 1. Unanswered Questions • What happens to water and nitrate that does not come out in subsurface drains? • Surface runoff? • More ET? • Deep seepage? (and… is it denitrified?) • Lateral seepage? (and is it denitrified?) • Researchable question, but funding not yet identified….

  4. Greenhouse gas question • Does some nitrate become N2O? Under what conditions? From www.keystone-graphics.com/webstore/

  5. Cumulative benefits question • What kind of nitrate load reductions are possible at the watershed scale?

  6. 2. Not all sites are suitable • (Isn’t this true for all practices?) • For example, most suitable in reasonably level topography and/or level drains. For retrofits: • Focus on flat land (we have plenty!) For new (expanded, intensified) system: • Encourage tile installation on contour (“drainage water management ready”)

  7. Timing of management may not match timing of drain flow Before planting or harvest After planting After harvest

  8. Subsurface Drainage as % of Precipitation Indiana 15-year average at Southeast Purdue Agriculture Center (Source: Kladivko et al)

  9. Water Quality Modeling of Fertilizer Management Impacts on Nitrate Losses in Tile Drains at the Field Scale. Nangia, Gowda, Mulla, Sands. JEQ 37:296-307 (2008) Note: February 1999 had 6 mm of drainage, or >50% of precip.

  10. Drainage management can increase surface runoff and associated pollutants

  11. 3. Unclear Benefits to Producers

  12. Yield impacts generally positive but small; sometimes negative GPS-enabled yield monitors used on all fields M F F M

  13. May be because managed drainage only raises water table in some conditions Ground surface Free Draining

  14. Profitability affected by factors other than crop yield The USDA NRCS may provide payment for the following practices: 554 Drainage Water Management 587 Structure for Water Control. Programs: EQIP, CSP, and GSWC. • For example, EQIP payments up to $40/acre/year in Indiana, but ends after 3 years.

  15. Why don’t more producers adopt drainage water management? • Farmers simplywant water to be gone. • Contractors don’t want to put the time into designing and installing it on the contour • They don’t see the benefit. A lot of people don’t care.

  16. Characteristics of practices that influence adoption • Relative advantage: the degree to which an innovation is perceived as being better than the idea it supersedes • Compatibility: the degree to which an innovation is consistent with existing values, past experiences, and needs of potential adopters. • Trialability: the degree to which an innovation may be experimented with on a limited basis • Risk • Observability: the degree to which the results of an innovation are visible to others

  17. Drainage water management is hard to observe • Does this hinder adoption?

  18. Accountability • We know drainage water management can improve water quality. • But it only will improve water quality if managed to do so. Before planting or harvest After planting After harvest

  19. Spot checks for 5 years will help

  20. Collecting more data would provide more assurance • Producers could receive annual payments by reporting dates they raised and lowered the outlet • Nitrate removed would be calculated using DRAINMOD

  21. Collecting more data would provide more assurance • Information could be used for adaptive management • The practice is sure to need further improvements as we understand more.

  22. http://www.ces.purdue.edu/extmedia/WQ/WQ-44.pdf

  23. relative advantage “is the degree to which an innovation is perceived as being better than the idea it supersedes” compatibility as “the degree to which an innovation is perceived as consistent with the existing values, past experiences, and needs of potential adopters.” Trialability is “the degree to which an innovation may be experimented with on a limited basis” Risk refers to variation in likely benefits or costs associated with a sustainable practice, variation in the effectiveness of the practice, and variation as to when the benefits might be realized observability as “the degree to which the results of an innovation are visible to others”

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