THE EFFECT OF THE BIPYRIDYL HERBICIDES ON HILL COMMUNITIES AND THEIR ROLE IN THE IMPROVEMENT OF HILL GRAZING

The improvement of hill land is important to the national economy of the United Kingdom. An increase in the amount of enclosed productive land results in a greater stock-carrying capacity of a hill farm. Improvement is not always possible by conventional implements, and herbicides are being used to kill the old sward. The bipyridyl herbicides offer a means of destroying or modifying the indigenous vegetation. The application of low doses of paraquat or diquat to an association containing Molinia caerulea, Nardus sfricta and Festuca avina resulted in a change in equilibrium in favour of the fescues. The application of 2 lb paraquat per acre practically eliminates all grass species in a sward and it is then possible to establish desirable pasture species after lightly cultivating the dead surface litter.     

THE EFFECT OF FERTILIZER NITROGEN AND FREQUENCY OF DEFOLIATION ON YIELD OF GRASSLAND HERBAGE

The effects of 4 levels of applied nitrogen, ranging from nil to a maximum of 417 lb N/ acre/annum, in all combinations with 3 frequencies of defoliation, ranging from 2 to a maximum of 10 cuts per annum, on herbage production from a perennial ryegrass/ timothy/meadow fescue/white clover sward were measured. These treatments were operative for 2J years, and in a subsequent year the residual effect of cutting frequency was tested. Dry-matter yields of total herbage and of the clover fraction are quoted, together with N yields of total herbage. Yield response to N was higher than in some other experiments in the U. K. Cutting frequency had a very large effect and, in general, the longer the interval between cuts, the higher was the dry-matter (though not the N) yield. There was a marked interaction between cutting frequency and level of N: at the high cutting frequency, dry-matter yield increased linearly with increasing level of N; at the medium frequency, response tended to fall off at the highest level of N; at the low frequency, yield declined with increasing level of N beyond 139 lb N per acre per anum.     

A COMPARATIVE STUDY OF PAPER AND OIL AS CARRIERS OF CHROMIUM SESQUIOXIDE ADMINISTERED TO GRAZING STEERS TO DETERMINE THEIR FAECAL OUTPUT

Two steers excreting similar quantities of organic matter daily were grazed at pasture during the summer of 1961. The four experiments each involved a preliminary period of five days dosing with Cr₂O₃ to reach a fairly constant excretion. The steers received a daily dose of Cr₂O₃ either in oil suspension or in shredded paper. The carriers and steers were interchanged for each trial. For two of the trials each steer in turn was harnessed every other day and all its dung collected in a bag. Total faecal excretion of organic matter was measured from the bagged steer and estimated from the Cr₂O₃ concentration in a composite sample made up from all dung pats voided during the ten-day collection period. In the other two trials the steers were not harnessed and each dung pat was separately sampled and analysed for Cr₂O₃ in the organic matter. The average recovery of Cr₂O₃ in the first two trials was 99·1 (oil) or 94·4% (paper). Calculating the faecal organic matter excretion from the concentration of Cr₂O₃ in the faeces and the quantity given daily overestimated it by 3·5 to 8·0%. There was no significant difference between shredded paper and oil as carriers of Cr₂O₃ for estimating the quantity of organic matter excreted. There were 37% and 22% less variation between dung pats in Cr₂O₃ concentration when this was administered in shredded paper than when given in oil suspension.     

THE INFLUENCE OF FERTILIZER ON THE WINTER SURVIVAL OF INTERMEDIATE WHEATGRASS FOLLOWING A LONG PERIOD OF DROUGHT

In Saskatchewan, intermediate wheatgrass ( Agropyron intermedium Host. Beauv.) suffered severe winter injury during the 1961–2 winter season, which followed a series of drought years, the most severe being 1961. In two tests, designed to study fertilizer effects, the extent of severe winter injury increased with the rate of application. The killing ranged from 4% where no fertilizer was applied to 90% where 66 lb of N per acre were applied. Slightly more winter-killing occurred after applications of ammonium phosphate/sulphate (16-20-0) fertilizer than after ammonium nitrate (33·5-0-0).
The grass growing in rows 36 in. apart killed out to a greater extent than that growing in rows 18 in apart Less winter injury occurred after spring applications of fertilizer than after application in the fall.     

THE GRASSLANDS OF EAST ANGLIA

Because in the past the main emphasis was placed on arable farming, grassland husbandry has played a minor role in East Anglia. Now the increased efficiency exercised in the arable farming of the area is being applied to the grasslands. The main trends are discussed.     

THE EFFECT OF HISTAMINE ON SILAGE DRY-MATTER INTAKE

The oral introduction of 0·5 g histamine as the diphosphate into the rumen of sheep produced no effect on the physiological condition of the animals. The feeding of histamine, as the dihydrochloride, in levels up to 1 g/day to sheep on silage diets did not affect the dry-matter intake.     

WILD WHITE CLOVER SEED PRODUCTION

A survey, covering some 140 fields, totalling 1540 acres, in Kent was conducted in 1961 on the effect of different methods of management on yields of perennial ryegrass and white clover seed. The main results were: (a) the majority of seed growers harvested seed from short-term leys and only a limited acreage of permanent pasture was used for producing seed. Yields of both ryegrass and clover seed were considerably higher on the younger leys; (b) the highest seed yields in 1961 were obtained from fields where sheep grazing was stopped on 24 May. However, a large number of growers continued sheep grazing well after this date: (c) mechanical defoliation, especially when used to supplement sheep grazing, proved an effective method for producing high yields of clover seed; (d) honey bees are important in increasing seed yields, particularly on recently sown leys; (e) combine harvesting from the swath was the most common method of harvesting and no instance of the use of tripods was reported. Seed yields from baling methods were generally low, but direct combining produced a high average yield of clover seed. From these results it was concluded that there was much scope for raising the general level of clover seed yields, especially by giving greater attention to details of management.     

Chemical Aids in Forest Fire Control

Progress in development of chemical aids in suppressing andretarding forest fires and in drying vegetation to facilitatecontrolled burning is reviewed briefly. The main part of thepaper describes exploratory trials in 1958–61, using arange of fire-retardant compounds for control of grass and heathfires. All chemicals tested were markedly superior to plainwater in checking fire spread. Ammonium phosphate solution,and ‘viscous water’ prepared using sodium alginate,were the most promising retardants tested, the latter beingthe more effective on heavier fuels such as heather and gorse.The costs and mechanics of use are discussed. Subject to operationaltrials, it is concluded that these chemicals could be of practicalvalue in checking the front and hottest parts of vegetationfires. Recent trials suggest that herbicides, of those testednotably Paraquat, may be used to desiccate grass vegetationto permit safe and rapid controlled burning during summer months.