The Effects of Different Primary Cultivations and Manurial Treatments on the Yield of Early Peas,Spring Cabbage,Leeks and Brussels Sprouts

The effects of different primary cultivations and manurial treatments on the yields of early peas, spring cabbage, leeks and Brussels sprouts grown in rotation on a sandy loam soil are described. The cultivation treatments consisted of deep ploughing, shallow ploughing-with-subsoiling, shallow ploughing, and shallow rotary cultivation, and these were combined fac- torially with three manurial treatments. Each of the crops in the rotation was grown in each year from 1954 to 1959. Special attention was paid to weed control and the experimental area was kept essentially free from weeds.

On average, the differences between the yields from the three ploughing treatments were small but, although the largest mean difference was only about 7%, several of the differences were significant.

The ploughing treatments gave significantly higher yields of all four crops than did shallow rotary cultivation ; the mean difference varied from 11% for peas and Brussels sprouts to almost 40% for spring cabbage.

Farmyard manure (FYM) with NPK fertilizers gave substantially higher yields of leeks/ spring cabbage and Brussels sprouts than nitrogenous fertilizer alone, but a smaller increase of only 18% in the yield of peas.

The following significant interactions are discussed : cultivations X years, manurial treatments X years, cultivations X manurial treatments and, for leeks only, cultivations X manurial treatments X years. It is concluded that the effects of some of the experimental treatments on the water available to the plant roots were, at least in part, responsible for some of the significant differences and interactions.

Certain aspects of experimental technique are also discussed.