Right after farmers take their last load of harvested soybeans to the bin, they should head back out the field and sample the soil for soybean cyst nematode.
According to Greg Endres, North Dakota State University Extension Cropping Systems specialist, right after harvest is when soybean cyst nematode numbers will be at their peak.
SCN is a parasitic nematode that completes two to three life cycles each growing season. Each female produces up to 200 eggs, which are protected within her body wall after she dies. This is what is referred to as the “cyst.”
Soil sampling allows farmer to measure the amount of eggs in the soil.
Soil sample right next to the harvested row. Farmers only need to probe 6 to 8 inches into the soil.
Take 10 to 20 small samples, then mix it together and fill a soil bag with the composite sample. NDSU Extension, in cooperation with the North Dakota Soybean Council, has information and bags for soil sampling that can be obtained at county Extension and Research Extension Center offices.
When soil sampling, look at areas where SCN may enter your field:
Field entrances. SCN can come in on soil left on a piece of equipment.
Low spots. These areas allow water to pool, and SCN can move in water.
Flooded areas. Locations that frequently flood are a prime location for SCN.
Along the edges. Areas around shelter belts or fence lines can have SCN.
High pH places. SCN thrives on high pH levels in the field.
Low yield zones. Do the soybeans look fine but yield poorly in one location? Soil samples can determine if SCN is the cause.
Yellow tint. Areas that turned yellow in August, or stunted or yellow beans, may be an indicator of heavy SCN damage.
Results from soil analysis indicate eggs per hundred cc of soil. Samples with 50 to 200 eggs indicate very low levels and should be viewed as suspicious. Numbers greater than 200 eggs should be viewed as a positive and managed.
SCN can explode very quickly, so finding levels close to 1,000 should be aggressively managed, so it doesn’t become 10 or 50 times higher after the next planting of soybeans or dry beans.