Tillage Methods Influence Crop Yields

Tillage experiments were conducted over a period of six years on four different types of soil; two sandy loams, a loam, and a clay loam. Crops were grown in rotation. Different implements were used to accomplish seven methods of tillage. The use of moldboard plow, followed by conventional tillage was considered as a method to be compared with three methods where machinery which mixed the existing vegetation with the surface soil were used. The possibilities of minimum tillage were studied by trying out different light tillage units attached to the standard moldboard plow. The value of deep tillage was studied by using the sub‐base plow. Results were measured by comparing the respective methods of tillage with regard to the efficiency of weed control and to the variation in yields obtained. The information obtained from these experiments may be summarized as follows: 1. Under the conditions which prevailed during these field studies, no method of tillage resulted in yields significantly greater than did the ones which involved the use of the moldboard plow. 2. Rotary tillage resulted in the lowest yields of all crops on all soils, with three exceptions, sugar beets on the loam, oats on the loam, and oats on the clay loam soil. 3. The other two tillage methods where the vegetation was mixed with the surface soil (auger‐type plow and vertical‐disk plow) resulted in yields intermediate between those from rotary tillage and conventional tillage. 4. The “once‐over” soil preparation methods were entirely satisfactory for all crops on all three types of soil. Yields were fully as high as those obtained where conventional tillage was employed. 5. Preliminary trials indicate that any device which smooths the soil sufficiently to make accurate planting possible, accomplishes all the tillage that is necessary for oats, sugar beets, and corn. Because field beans are planted so late in the season, they may require slightly more tillage.