South Dakota - Nutrient Management, Organic Farming, Wetlands

Within an hour to an hour and a half after a big rain, 4,000 acres drain onto one part of the Johnson farm. After a major rain, the water will flood from 5 to 20 acres--and stay just long enough to kill the crop and leave silt. So, the Johnsons have replaced their crops with a grassed waterway of 10 to 15 acres.

Charlie Johnson farms 1,800 acres in Madison with his brother, Allan. About 1,050 to 1,100 acres are in cropland with the rest in pasture, permanent pasture, sloughs, wetlands, waste ground, and buildings. The farm drains into the East Fork of Vermillion River and into the Big Sioux, which flows into the Missouri and the Mississippi rivers. Eighty-five acres of the home farm--three sloughs and 35 acres of permanent water that Johnson calls "a lake really, with clear, pristine water"--are under Water Bank Program contracts. When those contracts end, Johnson plans to fence a small area around the buffer strip around the water "and leave it permanently for wildlife. In the upland area, we'll leave it for the birds through the summer, and after the birds are done, in early fall we'd like to bring the cattle back to our home place for some nice fresh pasture."

Chuck Lebeda, Natural Resources Conservation Service (NRCS) District Conservationist in Lake County, says some of those acres may be eligible for the Conservation Reserve Program (CRP) when they come out of the Water Bank--"but even if they are not, we'll still get the natural resource benefit."

The Johnsons' farm has been organic since their father converted it in the mid-1970s. No herbicides or commercial fertilizers are used. Insects are controlled by the long, six-year rotations: alfalfa and hay the first two years, soybeans the third year, corn and/or small grains the fourth year, soybeans the fifth, oats and some alfalfa in the sixth year, and alfalfa beginning the cycle again in the seventh year. Alfalfa is the main component of weed control, Johnson says--"it's a smother crop"--and any weeds that do survive are harvested forage or hay--"so the cattle have a good chance of eating up your mistakes." Fertilizer comes from 120 cow-calf pairs and a small farrow-to-finish operation. The manure from both is composted, which Johnson says breaks the manure down, creates more balance, and makes it more granular and lighter to apply. This means fewer tons to the field, "which reduces hauling costs and it reduces nitrogen contamination." These farming practices may be labor-intensive, but input costs are controlled and the organic soybeans--whether exported to Japan for tofu or sold as feed for organic poultry and cattle in the U.S.--command a healthy price two to three times the going market rate.

A South Dakota State University research team has conducted wetland and buffer research on the Johnson farm for five years. Led by agroecologist Diane Rickerl, the team includes geographer Janet Gritzner, rural sociologist Donna Hess, and economist Larry Janssen, as well as Charlie Johnson and his wife, Bette. Their work compared buffered and non-buffered systems:

The analysis most useful to the farmer is the productivity and nutrient uptake of the buffer vegetation. Total nitrogen uptake was similar for the two systems, 173 ?pounds/acre in the non-buffered and 183 in the buffered. The nutrient removal in ?the non-buffered system was through the wetland vegetation. This nitrogen will ?continue to cycle through the wetland and is lost from agricultural productivity. In the buffered system, 101 pounds/acre of nitrogen were taken up by the buffer and ?can be utilized as hay. The trend was similar for phosphorus uptake in wetland ?vegetation and buffers. Wetland vegetation in the non-buffered system contained 24 pounds/acre P. In the buffered system, 13 pounds/acre were in the buffer ?vegetation and wetland vegetation P content was reduced to 9 pounds/acre. The ?amount of N and P contained in the wetland vegetation was less than half that of the ?non-buffered system.

Rickerl and Janssen then compared budgets for Johnson's fields with budgets for different farming systems and management scenarios. The farm management systems compared were transitional no-till, conventional, and organic. Each farming system was superimposed on a field with a natural resource base typical of the prairie pothole region. The wetland management scenarios compared were 1) farm through the wetlands, 2) use a buffer block around the wetlands and harvest it for hay, or 3) use the buffer block/hay system, but also enroll it in the Wetlands Reserve Program (WRP).

Rickerl and her team noted how powerful WRP is. They wrote, "A specific recommendation that can be made to farmers is that buffer strips improve environmental impacts of farming wetland landscapes. When coupled with programs such as WRP, buffer strips can also improve economic returns of farmed wetland landscapes." Johnson is pleased with the results--for wildlife as well as for the bottom line. He said, "Diane Rickerl has found we may not have so much an increase in the wildlife numbers, but we have a greater diversity of species around our wetlands because of organic farming."

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