Crop production and economic returns are principal drivers for producer decisions.  Conservation drainage practices must make economic sense and fit the operational needs of a farm for producer adoption and continued use.  A good surrogate for the more complex economic evaluation of the costs and benefits of conservation practices is Return on Investment (RIO) based on crop yield impacts.  This evaluation of investment costs per acre as compared to the estimated increases in crop yields from the conservation drainage practice(s) provides an estimate of the net return on the investment for these practices.  Further, the annualization of the net return provides an assessment of the number of years for a producer to realize the full ROI.  However, this ROI underestimates the value of the full suite of returns on the investment because it does not account for the ecosystem services benefits or community socio-economic returns.

The figure below summarizes ESE’s estimate of the ROI for three scenarios of applied conservation drainage practices where the base scenario of a subsurface drainage tile system is first improved with automated drainage water management (ADWM), and then improved further with the addition of subirrigation.  In all three scenarios the potential for state and/or federal financial assistance to the producer is not accounted for but would improve the estimated ROIs significantly.  For this assessment of ROI based on projected corn yield increases only, the ROI improves as conservation drainage practices are added to the base subsurface drainage tile system.  The estimated ROI improves from 14.6 percent to 30 percent with the addition of ADWM, and to 46 percent with the addition of subirrigation to the ADWM system.  Correspondingly, the number of years for the net returns to exceed the total investment improves from 6.9 years to 3.3 years, and then to 2.2 years with the subsurface drainage tile system plus ADWM and subirrigation.