Comparisons of costs and returns for different cropping and tillage systems are difficult to estimate. There are many different variables of production to consider with the amount and timing of rainfall at a particular farm being the most important. Soil health is also different for each of these alternative tillage and cropping systems.
Six different farmers in northeastern Montana were interviewed to determine their production methods and costs. Based on these interviews a generic typical farm was developed. This generic farm was used to estimate the different costs and returns for various cropping and tillage systems.
The six farmers interviewed had various production practices in their agricultural crop rotations. Conventional till, minimum till and zero till farming were utilized to raise cereal grains, pulse crops and annual legumes. Average annual precipitation ranged from 11 inches to 14 inches. Spring wheat, lentils, sunflowers, peas, flax, and mustard were grown.
Seeding rates in pounds per acre ranged from 60 to 90 for spring wheat, 66 to 80 for lentils, 1.3 to 3 for sunflowers, 180 to 212 for peas, 12 for yellow mustard, and 35 to 56 for flax.
Roundup was used for weed control in the spring before planting on many of the no/zero till acres. Other herbicides used for weed control were Discover, Bromac, 2,4-D LV 6, Clarity, Spartan, Bronate, Assure, Sonalan, and Weedmaster.
Some fertilizer was applied and incorporated in the fall, incorporated or broadcast in the spring prior to planting and/or applied at seeding with the drill. The most common granular formulations were 46-0-0 urea and 11-52-0 super phosphate. Many operators also used a fertilizer blend.
A Soil Tillage Intensity Rating (STIR) was used to evaluate the effect of tillage on soil health in each of the different systems. A STIR with a low value has the least adverse effect on soil health. Over time, a system with a low STIR value will have the least effect on soil structure and overall soil health. Generally a low STIR will improve organic matter, fertility, productivity, water holding capacity and soil structure. For example, a no-till continuous cropping system can have a STIR rating as low as 3. A minimum till cropping system composed of two crops and one minimum till fallow will have a STIR rating ranging from 70 to 80. A conventional tillage crop-fallow system can have a STIR rating of 100 or higher.