2017 study looks at impacts of diversified crop rotation

SDSU Extension
Farm Forum

BROOKINGS — Throughout the 2017 and 2018 growing seasons, a team of researchers from South Dakota State University will be assessing the impacts of diversified crop rotation cropping systems compared to traditional corn-soybean rotation. The study will also review the impact cover crops have on soil health and crop yields. The study, Crop Diversification on Soil Health and Farm Profitability in South Dakota, is funded by Natural Resources Conservation Service (NRCS) Conservation Innovation Grant in 2016.

“Past studies have shown that diversified crop rotations build soil health and result in insect, weed and disease control as well as many other environmental and economic benefits,” said Tong Wang, SDSU Extension advanced production specialist. “However, in recent years, only two crops – corn and soybeans – make it into the rotation of most South Dakota farmland.”

Wang is one of two main investigators on the project. She is joined by Sandeep Kumar, assistant professor in the SDSU Plant Science Department.

The two-year study will look at two South Dakota farm sites. The sites will include a two-crop, three-crop and four-crop rotation system. Each rotation system will be ranked in terms of total input cost and economic profit with and without subsidy.

“This study will demonstrate the impacts of diversified agroecosystems – corn-soybean-wheat, corn-soybean-wheat-oats, corn-soybean-oats and cover crops and no-till systems – on soil health and economic benefits in South Dakota,” Kumar said.

A good time to consider diversified crop rotation

Wang added that the study aims to increase awareness among producers about crop diversification such as corn-soybean-wheat, corn-soybean-wheat-oats, corn-soybean-oats and cover crops and no-till systems impact on soil health and economic benefits.

“Diversity of crop rotations is important to soil health and farm profitability – today and into the future,” Wang said.

The corn and soybean-only rotation seen on several South Dakota farms is thought to have been driven by market highs. Around 2012, the price-per-bushel for these two crops peaked with corn at $7.39 per bushel and soybeans receiving $16 per bushel.

Just five years later, the markets look much different. According to the Feb. 9, 2017, the U.S. Dept. of Agriculture, Agricultural Supply and Demand Estimates the projected season-average corn price for 2017 is $3.20 to $3.60 per bushel, while the soybean price is between $9.10 per bushel and $9.90 per bushel.

Today’s market lows give farmers an opportunity to consider re-introducing crop diversity into their farm fields.

“The low corn and soybean market prices together with increasing production costs in recent years have squeezed much of the profit out of the traditional corn-soybean rotation,” Wang said. “Producers may consider adding crops like wheat and oats to the rotation.”