The main conclusions that can be drawn from these field experiments to compare the effect of different methods of preparing the seed bed on the crop's growth are:

(1) Crops germinate faster on the looser seed bed prepared by a Rototiller than on the more compact ones prepared by a plough or a grubber. The total number of plants that germinate is, however, the same for all treatments unless the land is too foul with weeds, when higher germination is obtained on the cleaner plots.

(2) Cereals tend to ripen a little sooner on land that has been ploughed than on land that has been either rototilled or grubbed, but in most years this effect if present is very small.

(3) The shape and the weight of the mangold root seems to depend on the seed bed. The roots were longest and thinnest on the deep-ploughed plots and were always squatter on the shallow-tilled than on the deep-tilled plots. The roots were heaviest on the deep-ploughed plots and lightest on the rototilled plots. On the rototilled and the grubbed plots the depth of tillage had no effect. The plants on the shallow-grubbed plots seemed, however, to have no reserve of strength, for they could not make better growth if given more room, while those on the deep-grubbed plots could make some use and those on the ploughed or rototilled plots appreciable use of extra space.

(4) Weeds tend to accumulate on the rototilled and the grubbed plots since neither grubbers nor rotary cultivators carrying tines mounted on a horizontal shaft can bury weeds and weed seeds in the way that the plough can. If the land is fairly clean and in good heart this probably does not matter for several years, but it prevents either of these from completely displacing the plough.

(5) A subsidiary result that emerged from these experiments is that if a thin crop is given a nitrogenous top dressing, the fertilizer may benefit the weeds more than the crop.