Effects of soil cultivation on the growth and yield of winter wheat. I.—soil cultivation and winter survivals

Abstract

Abstract1. The effects of three types of soil preparation—ploughing to 8 in., use of a cultivator 3 to 4 in. deep or more, shallow cultivation to 1 1/2‐2 in.—on the winter survivals of wheat were examined on six farms and during three seasons.2. The effects varied with the type of soil and with the season; open‐textured and light soils were the chief types in which winter survivals were affected by cultivation. In ploughed and 4‐in.‐cultivated soils winter survival was superior to that in shallow‐cultivated soils in mild seasons; the reverse was true in the severe winter of 1946–47.3. In the moderate seasons of 1945–46 and 1947–48, early frost caused higher mortality after shallow cultivation as a result of the shallower placement of seed. In the severe winter, with deeper ground‐frost, of 1946–47, the relative depth of penetration of frost into the soil in the arable layer was the factor primarily concerned in producing greater frostinjury to the plants in the ploughed and deep‐cultivated plots, as compared with the shallow‐cultivated. The seed‐bed left after shallow cultivation was more compact than that after ploughing or deep cultivation and seemed to be associated with the effects of different types of cultivation on winter survivals in 1946–47.4. It is suggested that early sowing of the crop with shallow cultivation to about 2 in. would reduce the risk of frost injury in the open‐textured and light soils during moderate as well as severe winters. Sowing must be early enough to ensure good establishment of the plants before the frosty periods.5. Varietal differences in susceptibility to winter killing were of the same order under the three types of cultivation treatments and in all soils. Neither cultivation nor varietal selection alone could give a normal stand in a severely affected soil such as Burdiehouse. In such soil, shallow cultivation (2 in.) and use of a frost‐resistant variety would probably give a stand of plants equal to that in a soil in which no frost injury occurred.