The growth and development of a crop of Bulrush millet (Pennisetum typhoides S. & H.) was evaluated by a series of ‘first’ harvests at weekly intervals during the growing season. A final harvest was taken at the end of the season to measure the regrowth.

Tillers emerged from the second, until the 5th week after emergence where full light interception was recorded. Then a marked increase in dry-matter production, internode elongation and leaf area index occurred and a peak growth rate of 44 ± 4 g. of dry matter per square metre per day was recorded during the 9th week. General flowering occurred during the 13th week and at 16 weeks the crop yielded 21,735 kg. of dry matter per hectare.

Regrowth yields were high following defoliations made at an early vegetative stage when the apical meristem was below the cutting height and then declined as internode elongation raised increasing numbers of apices above the cutting height. Extensive areas of the stand died when defoliated as it approached its period of maximum growth rate.

1. Oestrous activity was studied in three groups of eight Southdown ewes exposed respectively to natural lighting (30½° S.), accentuated reversed seasonal lighting, and equatorial lighting for a period of 2 years.

2. Control ewes exhibited a restricted breeding season confined to the autumn and winter months of each year. The breeding season averaged 102–5 days in length and during it the ewes experienced an average of 7·14 ± 0·47 oestrous periods.

3. The natural breeding season was almost completely reversed by artificial reversal of the normal seasonal variation in daylength. This constitutes presumptive evidence that daylength is the major factor controlling seasonality of oestrus in Southdown ewes.

1. Data are presented to show that, in the United Kingdom, soil temperatures do not fall more than a few degrees below freezing point even during prolonged spells of abnormally cold weather.

2. Two methods of assessing cold resistance in cereals are described in which the natural gradient between air and soil temperature is maintained. These involve the use of seed boxes 6 in. deep in one case and a portable field freezing cabinet in the other.

A variety of irrigation régimes were applied to a rye-grass/white clover sward, at several nitrogen levels, in small-plot field experiments.

Herbage yields increased with decreasing soil moisture deficit.

No outstandingly good irrigation régime was found, but some distinctly poor practices were identified, by reference to the yield per unit of irrigation water and to the shape of the annual growth curve. The significance of the results for irrigation practice is discussed.

Tho authors wish to thank Dr William Davies for the provision of facilities, Mr R. J. Canaway and his staff who made the irrigation apparatus, many past and present colleagues who helped with the field work, and members of the Biometrics Department who analysed the data.

A series of forty-two factorial field trials in 1959–62 tested the effects of 0·6 and 1·2 ewt./acre of N; 0, 1·2 and 2·4 cwt./acre of K2O; and 0, 2 and 4 cwt./acre of salt on sugar beet. Extra plots received 0 and 1·8 cwt./acre of N.

On average, 0·6 cwt./acre of N was more profitable than 1·2 cwt./acre. There was a positive interaction between N and Na, and a lesser one between N and K; in presence of the heavy salt dressing, or the light salt dressing and potassium the optimum rate of nitrogen was 1·0 cwt./acre.

1. The point at which continued development of a seed no longer depends upon attachment of the culm to the root system can be termed rootindependence.

2. Serially harvested inflorescences of Lolium temidentum L. were maintained in a glasshouse under the same environmental conditions as standing material. Samples for analysis were taken from harvests and standing material at 2 days intervals to compare chemical changes occurring in seed on standing and severed culms. Analyses for total soluble carbohydrate (T.S.C.) were performed on a single seed basis.

3. Harvests made before the seed T.S.C. maximum resulted in oscillating changes in endosperm free sugar content and these caryopses tended to stabilize at an excessively high value. All later harvests resulted in seed with a final T.S.C. level within 1% of that present in normally matured seed

4. 14C-Sucrose uptake studies showed that tho endosperm T.S.C. requirement was high prior to the seed T.S.C. maximum but that it was very low during the second half of the maturation sequence. It is considered that during this period sugar is only translocated to make good respiratory losses.

1. The effects of applied nitrogen (0, 200, 400, 600, and 800 lb. per acre per annum) and spacing (widely spaced plants and simulated monoculture swards) on average yields and yield components of eight clones of Lolium perenne are reported for four harvests taken each year during 1962 and 1963.

2. During both years, higher yields per unit area were obtained from swards than from spaced plants; the degree of difference varied from harvest to harvest.

3. A greater effect of nitrogen on yield was detected in 1963 than in 1962, an effect especially marked in swards at lower rates of nitrogen application. A highly significant nitrogen x spacing interaction on yield was detected in 1963.

Acetic acid, propionic acid, and butyric acid were fed to lambs at a level of 4% of ration over the period of 3-8 weeks of age. The effects of this on weight gains and rumen development were measured.

Separate pathways are involved in the metabolism of C3 and C4 V.F.A. in the rumen wall, and the enzyme systems involved can adapt to high levels of each acid in the diet. The adaptation is longstanding.

The groups of lambs supplemented with propionic acid showed greater weight gains than the other groups.

Propionic acid in some way increases the efficiency of V.F.A. utilization by the animal, possibly by reducing the heat increment, and/or reducing loss of energy as ketone bodies in the urine.

At 9-12 weeks a higher efficiency of food utilization in the acetic acid group was observed.

The stimulatory effect of acetic and propionic acids on papilla numbers was observed at 8 weeks.

Some observations were made on histological sections of rumen papilla at 8, 12 and 16 weeks and their relationship to the diet.

1. The yields and yield components are recorded for selected clones of Lolium perenne, grown at different levels of applied nitrogen (0, 200, 400, 600 and 800 lb. of nitrogen per acre per annum) and at two spacings (widely spaced plants and simulated monoculture swards). Four harvests were taken in each of the two years 1962 and 1963.

2. In both years there were significant and consistent differences between clones in their drymatter production per unit area, detectable at both spacings. A genotype x spacing interaction was detected only in 1962. A genotype x nitrogen interaction at some harvests was not found on annual totals.

In a series of experiments in which variations in the level of carbohydrates in the plant have been brought about by means of short-term exposures to darkness and raised temperatures, it has been shown that:

1. The yield of leaf material after cutting is affected by pretreatments. This effect seems to be at least partly associated with the level of carbohydrates present in the stubble at the time of cutting.

2. The rate of growth of the plants is independent of the pretreatments imposed once growth is fully established.

1. The problem of when to apply nitrogenous top-dressings to winter wheat has nover been satisfactorily solved. Detailed field and glasshouse experiments on the effects of nitrogenous manuring on the development of wheat plants, and a number of other experiments involving the nitrogenous manuring of wheat are described and the results discussed.

2. Partial regression coefficients of grain yield on individual components of yield are used to show how variable is the relationship between grain yield and the components of yield.

3. It is concluded that field experiments are never likely to determine an optimum time for nitrogen top-dressing because of the unpredictable relationships between individual yield components and grain yield, and because of the variation in response to nitrogen introduced by seasonal and environmental factors.

The physical wool characteristics of 268 Iraqi Awassi ewes were studied in 1963, as well as the relationship between some of these traits. The overall average grease fleece weight, clean wool percentage, staple length, fibre length, fibre diameter and degree of crimp were 3·77 lb., 84·85%, 16·47 cm., 17·37 cm., 33·32/t and 4·18 crimps per 2 cm. respectively. These attributes class the Awassi wool as a carpet wool.

Age proved to have no significant effect on any ofthe traits examined. Significant positive correlations were found between grease fleece weight and fibre length and between number of crimps and fibre diameter, while a significant negative correlation was found between clean wool percentage and fibre length.

1. An investigation into the effects of plant population level and irregularity of plant spacing on the yield and quality of swedes is reported.

2. There was no significant evidence that irregular plant spacing, such as might be produced by mechanical singling, gave a lower yield than regular spacing.

3. Total yield of roots was similar for all plant populations tested (range 15,000–50,000) but at low populations both the number and weight of diseased roots was greater than at higher populations.

4. As the population was increased, the drymatter percentage in the roots increased due to the higher proportion of skin on small roots compared with large roots.

1. Three hays of Coastal Bermuda (Oynodon dactylon) grass and three hays of Pangola grass (Digitaria decumbens) from grasses cut at different stages of maturity were used for the determination of digestibility coefficients, voluntary intake, rate of passage through the gut, production of total and individual volatile fatty acids, total counts of bacteria determined microscopically and examination of bacterial types present using Gram-stained smears. The animals used were individually housed sheep.

2. The hays of Coastal Bermuda were significantly superior to those of Pangola from the point of view of digestibility. Significant differences did not exist within grasses.

3. The hays of Coastal Bermuda were superior to those of Pangola from the point of view of intake although this was not significant.

4. No relation was evident between digestibility of the various hays and rate of passage through the digestive tract; it was concluded that intake was not limited by rate of passage through the gut.

Artificial rearing involves the replacement of those contributions made by the ewe which are essential to the growth and development of the lamb. This not only includes the supply of food but also the warmth, shelter and ‘mothering’ normally provided by the ewe.

Relatively little information is available on the artificial rearing of lambs. The earliest report, perhaps, is that of Mumford (1901) who bottle-fed the milk produced by eight ewes to four lambs. The more practical aspects of rearing orphan lambs have been described by Preston (1958) and Caldwell (1957). More recent reports on the artificial rearing of lambs have been made by the Grassland Research Institute (1959–60, 1960–61), Cunningham, Edwards & Simpson (1961) and Large (1962).

1. Groups of twenty-four heifers were used in three experiments lasting 51–98 days. The effect on rate of live-weight gain of the addition of 150 ml. cod-liver oil to the daily ration was studied.

2. The same treatments were used in each experiment: a basal diet consisting of hay and concentrates and two experimental diets consisting of the basal diet plus (a) 3 lb. concentrates, (b) 150 ml. (0·30 lb.) cod-liver oil. In one experiment flaked maize was used in the concentrates in place of crushed barley.

1. Cuts of elephant grass (Pennisetum purpureum were made at 40–60 (trial 1), 30 (trial 2), 50 (trial 3) and 70 (trial 4) days of age. Determinations of voluntary intake, digestibility coefficients, rate of passage through the gut, time spent eating and ruminating, number of boluses, rate of chewing, production of volatile fatty acids (both total and individual) were determined using individually housed sheep.

2. Digestibility coefficients of crude protein declined with the level of crude protein in the forage; digestion of the crude fibre fraction declined with advancing maturity. The digestibility of N.F.E. increased with increasing maturity resulting in similar values for T.D.N. among the four cuts. Digestibility of dry matter of the grass in trial 2 was significantly higher than that for the other three trials.

1. This paper reports on two experiments, one conducted in the field, the other in a cold cabinet. These had three objectives: (i) to examine the effects, on yield and some components of yield in certain grass varieties, of various combinations of frequency and intensity of defoliation, (ii) to compare these effects in the two environments, and (iii) to assess the value of very small plots.

2. Records were taken of the major environmental variables in the field; the chosen environment in the cabinet was quantified.

3. In the field trial, the cutting treatments comprised all combinations of two frequencies (herbage cut when 8 in. and 4 in. in length) and two intensities (cut back to tiller lengths of 2 in. and 1 in.) plus a fifth treatment of cutting at a silage stage back to a tiller length of 1 in. The first four treatments were also used in the cold cabinet trial. S170 and North African tall fescue were common to both experiments; in addition, S22 Italian rye-graes was included in the field trial. In both trials, plots consisted of four rows of seven plants, square planted at 2 in. x 2 in.

1. The effects of irrigation and fertilizer nitrogen treatments on four swards were studied for 3 years in an experiment at the Hannah Institute. This paper describes only the effects of the fertilizer nitrogen treatments and their interactions with the presence or absence of clover in the sward, since those of the irrigation treatments have been reported previously.

2. Annual applications of 0, 104, 208 or 312 lb. of fertilizer nitrogen per acre were made on swards of S 23 rye-grass or S 37 cocksfoot with or without S100 white clover.

3. The yields of the grass + clover swards exceeded those of the pure-grass swards at all fertilizer nitrogen application rates in the first 2 years and at the 0 and 104 lb./acre rates in the third year.

1. Loss of ignition at 450°C. and the organic carbon content of some shale soils are positively correlated (r = +0·99).

2. Base exchange capacities and exchangeable cations were determined on soils, treated and untreated with hydrogen peroxide solution.

3. Oxidizing the organic matter lessened the exchange capacities of all samples; the exchange capacity of the organic matter varied from 67·5 to 97·0 m-equiv./1OO g. dry material.