There are many advantages of reducing soil tillage. However, reducing tillage creates concerns of yield reductions due to cool, wet soils in the poorly-drained landscape that dominates much of North Dakota and the Red River Valley. The objectives of this study are to:
- monitor soil warming and water contents under chisel plow, vertical tillage, strip till with shank, and strip till with coulter on various soil series
- evaluate soil health and crop yields, and
- transfer information to producers through field days, videos, etc.
This is a multi-state effort, involving North Dakota and Minnesota and is in year four of the field study. Four on-farm locations are under a corn-soybean rotation and rotate each year. At each location, the four tillage practices are demonstrated using full-sized equipment in plots of 40 feet wide by the full length of the field in a replicated design. Soils include silty clay, clay loam, loams, and sandy loam; representing >67 million acres in the region.
During 2017, the chisel plow and strip-till berms had the driest and warmest soil conditions followed by between the strip-till berms and then the vertical till as the wettest and coolest soil conditions. These results are consistent with our observations during previous growing seasons in this study. In general, soil temperature and moisture differences among the tillage practices are greatest in the sandy soils and least in the clayey soils. This is likely due to the clay soils ability to readily rise water from deeper layers into the seedbed, which is less pronounced in the sandy soils. Soil microbial communities appeared to be relatively stable over time during the year.
No differences were observed in corn stand counts or yields at the two field sites with corn grown during 2017, with an average of 187 bu/ac on the loamy soils and 198 bu/ac on the sandy soils. Additionally, no differences were observed in soybean yields at the two fields sites with soybean phase of the corn-soybean rotation were grown in 2017. However, tile drainage appeared to have substantially larger influence on soybean yields than tillage or soil salinity level. For instance, soybean yields varied by 3.9 bu/ac on average among tillage practices, regardless of the soil salinity levels or drainage management. The same variability was observed among soil salinity levels. However, crop yields were 7.5 bu/ac higher in tile drained fields as compared to undrained fields.
This project has was produced three videos (viewed >9,800 times from around the world), disseminated information at >50 field days, presentations, and other university events to deliver study findings to North Dakota producers, and the Upper Midwest Tillage Guide that was published in 2017 and is available online for free. Information obtained during the 2018 growing season will be presented at joint NDSU-UMN events in 2018.