F. Hanley

The effects of fertilizers on the bulking of Majestic potatoes

1. Four experiments designed to investigate the effect of fertilizers on the rate of bulking of Majestic potatoes are described and the results discussed. 2. Irrespective of fertilizer application yield increased until the haulm died and then decreased slightly. 3. Sulphate of ammonia increased the yield by increasing the number of tubers and increasing the yield in all size-grades. Thus its effect was seen throughout the season, no matter what grades yield was based on. It also increased dry-matter percentage.

The effects of consolidating the soil beneath potato seed tubers and of inter-row grubbing on the growth and yield of the crop

1. Three experiments designed to investigate the effects of consolidation and aeration of soil beneath potato seed tubers before planting, and inter-row grubbing after planting, on the growth and yield of potatoes are described and the results discussed. 2. Consolidation of furrows beneath seed tubers by tractor wheels at planting had no effect on total weight of ware-size tubers produced but increased the weight of mis-shapen waresize tubers. It is argued that this effect was related to soil moisture content and tilth at planting time.

Studies on lucerne and lucerne-grass leys II. The nitrogenous manuring of a lucerne-cocksfoot ley

An experiment, carried out to determine the effect of dressings of sulphate of ammonia on an established lucerne-cocksfoot ley grown in narrow rows on heavy gault clay soil, is described and the results discussed. The experiment was carried out over 3 full years (1948–50) and the first crop of the following year. The results suggest that it is possible to increase the yields of grass and total produce without decreasing the yield of lucerne but that no marked increase in the yield of nitrogen per acre is to be expected. Of the times of application tested February proved the most effective.

The effects of leys and their management on the yield of succeeding wheat crops on heavy land

1. One long-term experiment comparing the effects of leys and arable cropping on the yield of arable crops and three experiments on the effect of management of lucerne/grass leys on the following arable crops, all conducted on heavy clay land, are described and the results discussed. 2. In the first two years after breaking a ley yields of wheat were higher than on plots which had had all-arable cropping and it is suggested that this effect could be due to a combination of disease and weed control and the nitrogen status of the soil.

Results from three cycles of six-course rotations on light land

A rotation experiment comparing the effects of length, type and management of leys on three test crops in six-course rotations during three cycles is described and the results discussed. Although the yields of the test crops varied from cycle to cycle there were no clear-out trends to suggest that the yield improves or deteriorates as time goes on with these particular rotations; the full benefit of the leys was obtained in the first cycle. The yield of potatoes immediately following the leys was no greater than the yield in an all-arable rotation receiving adequate nitrogen fertilizer, but the yields of two, barley crops following the potatoes were less in the all-arable rotation than in ley rotations even when 58 kg N/ha/year and 38t dung/ha/cycle had been applied and trefoil ploughed-in in the all-arable rotation. Rotations containing lucerne or lucernecocksfoot leys gave their greatest yields of potatoes and of barley following potatoes without any applied nitrogen fertilizer, but in the second barley crop showed the same sort of nitrogen responses as the all-arable rotation. Yield data were also obtained on the leys themselves in each cycle. These showed a decline from the first to third cycle in yield of broad red clover grown as 1-year leys and in that of 3-year leys which contained lucerne, both of which could be explained by the build-up of specific diseases. There were also changes in the effect of grazing compared with mowing on the yield of some leys but little change in the effects on leys of applying nitrogen to them. However there was no suggestion that these changes affected the arable crops that followed.

The effect of date of winter grazing on the yield of a lucerne-grass ley

It has been shown that lucerne/grass mixtures, especially those containing a high proportion of cocksfoot, can make a valuable contribution to the winter feeding of livestock when the autumn growth is allowed to stand in the field until the winter. For instance, Hughes (1954) showed that it was possible to carry store cattle right through the winter on such herbage with little supplementary feeding. Other experimental work (Barker, Hanley & Ridgman, 1955) has shown that mowing or grazing this autumn growth in September may lead to poorer production in subsequent years than October defoliation. It therefore seemed desirable to determine the effect of date of grazing in the winter on the subsequent yield of a lucerne/grass ley and two experiments for this purpose were carried out at Cambridge from 1953 to 1957.