In his 2008 novel, Driftless, David Rhodes writes, "In southwestern Wisconsin there is an area roughly one hundred and sixty miles long and seventy miles wide with unique features. Its rugged terrain differs from the rest of the state. The last of the Pleistocene glaciers did not trample through this area, and the glacial deposits of rock, clay, sand, and silt – called drift – are missing. Hence its name, the Driftless Region. Singularly unrefined, it endured in its hilly, primitive form, untouched by the shaping hands of those cold giants."
With its steep ravines and streams flowing to the Mississippi, Wisconsin's Driftless area makes an ideal locale for changing agricultural practices to enhance water quality. Farming in the region takes place on ridge tops and river bottoms that are vulnerable to erosion and nutrient loss. Tom Cox, who studies farm sustainability and profitability, Peter Nowak, a soil and water conservation specialist, and several others have launched a multi-year initiative to better understand why a disproportionate amount of pollution comes from only a small number of farms.
Non-source point water pollution -- mainly in the form of sediment and phosphorus run-off from fields -- has been a public concern for many decades. But remediation proposals, such as buffers along waterways, have caused controversy and stalemate. Finally, in 2002, Nowak and colleagues organized the Wisconsin Buffer Initiative, bringing farmers to the table with scientists to design recommendations that after three years of collaboration are being considered at the state level. But they have never been tested.
Because much of the sediment and nutrient loss is coming from just 8 of the 62 farms in the targeted watershed, the researchers want to develop site-specific recommendations for those "high export hot spots." They hope that understanding the whole-farm management process can help point the way to corrective practices that will work, be cost-effective, and gain wider adoption.
Photo: Curt Diehl, Dane County Land Conservation Division
High fertilizer application, soil-disturbing tillage, non-crop periods where plants are unavailable to take up nutrients, and heavy rainfall all contribute to nutrient run-off. This is where dialog with farmers comes in: "An inappropriate decision in a vulnerable location or time will have a disproportionate impact on the watershed. Yet we have very little understanding from the farmer's perspective of why [this] occurs…and most important, what it will take to change the nature of this … decision," the researchers write.
Cox suggests low-cost measures, such as sowing cover crops following corn-silage harvest or adding soil-retaining grass to alfalfa fields, that can make a big difference in the short term. "We look for win-win options that meet specific farmer objectives and constraints," he notes.
Two watersheds in the Sugar/Pecatonica River Basin will serve as treatment and control areas for the study. Both are ranked highly for improvement potential. In addition to logging farmer decisions, the team will look at poorly understood physical processes, such as how sediments and phosphorus are transported in ephemeral drainage channels. Hoping to avoid the assessment errors that have plagued larger watershed-scale studies, they will use improved measurement techniques to develop a GIS-based watershed inventory identifying vulnerable fields.
This project has great potential to work at larger scales in working agricultural landscapes throughout the Upper Mississippi River.
-Steve Richter, Nature Conservancy Director for Southwestern Wisconsin
Once the physical, economic and social processes are better understood, the research team will create a decision-aid to help conservation planners, regulators, and land managers choose management changes to improve water quality. "Our research seeks to both develop and validate decision tools that will quantify the economic and environmental trade-offs facing farmers," Cox says. By collaborating with land users, county conservation staff, and state agencies the research team hopes to boost the impact of their findings through extension education programs.
Support for the research comes
from the Wisconsin Water Science Center of the U.S. Geological Survey, the Nature Conservancy, the USDA Ag Research Service, the Dane County Land Conservation Division, and University of Wisconsin Extension.