Strip-till tips for the northern Plains
The trend among northern Plains farmers is toward using less tillage to produce field crops with more residue left on the soil surface and strip-till is one system being utilized in the area. Researchers from South Dakota State University detail some of the benefits and considerations for implementing and managing strip-till.
Advantages of strip-till include, reduced soil erosion because most of the soil remains covered with crop residue throughout the year, increased water infiltration compared with full-field tillage, less carbon released into the atmosphere and higher levels of soil organic matter and crop yields that are similar or higher compared to other tillage systems.
Other benefits include, better seed germination and plant emergence because the tilled strips warm sooner in the spring, soil moisture conservation because most of the soil surface area is covered with crop residue and reduced expenses, including fuel and labor, by eliminating some primary and secondary tillage.
Strip-Till Improves Carbon Sequestration
Soil organic matter plays a critical role in the global carbon cycle. Soil can act as both a major source for carbon released into the atmosphere and a sink to store carbon. When carbon is stored in the soil, it is not released to the atmosphere as greenhouse gases, particularly carbon dioxide (CO2) and methane (CH4). Tillage increases microbial action on organic matter stored in the soil and normally increases the rate of decomposition that changes organic carbon into CO2. Soil organic matter is directly related to soil fertility and positively correlated with agricultural productivity potential.
Besides reducing greenhouse gases, other advantages of increasing or maintaining a high level of soil organic matter include reduced soil erosion, increased resistance to compaction, increased biological activity and enhanced soil fertility. Since tillage results in soil carbon loss, identifying tillage methods that reduce the amount of carbon released into the atmosphere is important.
A comparison study of soil CO2 emissions following fall moldboard plowing, disk ripping and strip tilling conducted in 2005 in Minnesota (Faaborg et al., 2005) determined that strip tillage maintained more soil carbon than moldboard plowing and disk ripping. Disk ripping and strip tillage released 53.2 and 82.6 percent less CO2, respectively, than moldboard plowing (Figure 1). Moldboard plowing disturbed and exposed the greatest amount of soil, allowing carbon previously stored as organic matter or present as CO2 in the soil atmosphere to escape into the atmosphere.