1. Frequent soil sampling to 10 ft. depth was carried out on irrigated and unirrigated plots and, with the assistance of rainfall data, fairly accurate measurements of water uso were obtained unless the soil was at, or near to, field capacity. Evapotranspiration could then not bo distinguished from drainage beyond the root range.

2. A previous method of relating the water uso of unirrigated coffee to the readings of a sunken evaporation pan was shown to be reliable. The relationships between the water use of unirrigated coffee and meteorological factors (Penman's Eo, sunken pan evaporation or solar radiation) were shown to be dependent on soil-moisturo deficit, and on this basis a more precise method of predicting water use from sunken pan evaporation is proposed. When this method was applied to meteorological data from earlier years, good agreement was obtained between measured and estimated quantities of water in a 10 ft. profile.

1. An experiment was carried out in 1961 and 1962 to test the effect of the application of high levels of fertilizer N to S 23 ryegrass swards on the health and performance of grazing calves. A uniform application of 47 kg. P and 75 kg. K/ha. was used in each year. Nitro-chalk was applied at monthly intervals from February to September, at rates equivalent to 22.4 kg. (Nl) and 112 kg. (N3) per hectare in 1961; in 1962 an intermediate rate (N2) of 67.2 kg./ha./month was also used. The total quantities of N applied per hectare in 1961 were 185 and 1042 kg. and in 1962, 192, 576 and 961 kg.

2. Male calves, 2-6 months old when introduced to the experiment, grazed in rotation round a series of four paddocks on each treatment. In 1961 Friesian, Aberdeen Angus cross and Shorthorn twin calves were used; in 1962 all the calves were unrelated Friesians.

The Awassi flock raised at the Abu-Ghraib Experiment Station over the years 1960-64 produced 923 single and 88 twin births. The environmental factors affecting birth weight, and the repeatability of birth weight were investigated.

Sex of lamb, type of birth, weight of dam, time and year of lambing were found to have significant effects on the birth weight of Awassi lambs. Male and single lambs were heavier at birth than female and twin lambs respectively. Ewes weighing between 126 and 135 lb. produced the heaviest lambs at birth. Lambs born earlier and later in the lambing season were heavier than lambs dropped in midseason.

Variations in the time of onset of the breeding season in Clun ewes have been studied during the four years 1962-65. Differences within seasons were studied in 1963 and 1964 by scattering the lambing over the first 7 months of the year. The date of first service then appears to be very highly dependent on the date of previous lambing. Time of previous weaning appears to be less important.

Very highly significant differences have been found between seasonal means and these differences have been shown to be significantly related to the mean ambient temperature during a limited period between mid-summer and the mean date for the resumption of cyclic activity in the ewes. The higher this temperature the later the onset of breeding activity. Over the years individual ewes have tended to breed consistently either early or late.

Behaviour of lambs was studied in three separate physiological states resulting from planned exposure to cold, i.e. energy reserves depleted, discomfort during the experience of cold, and hypothermia.

When lambs were observed under mild conditions, prior depletion of about 20 % of the energy reserves, due to exposure to cold conditions for 4 hr., was without marked effect on teat-seeking activity. However, when the lambs were observed under cold, wet conditions, there was a marked depression of this activity. The activity in lambs which had been kept warm to conserve energy also tended to be depressed under conditions of discomfort due to cold.

1. A study of the suitability of rations of predominately sorghum grain for the intensive finishing of steers is reported. Six groups, each of ten steers, 18 months old and of an average body-weight of 544 lb., were fed, according to a set schedule, increasing quantities of grain in the ration until two groups were each consuming rations containing 80, 90 or 100% grain. One of the two groups, fed each grain-to-roughage ratio, received 60 g. urea per head daily. Individual steers were slaughtered when they attained 900 lb. body-weight. A seventh group of ten comparable steers was slaughtered at the commencement of feeding in order to measure changes in body composition due to the nutritional treatments.

1. Net pasture dry matter production and available pasture dry matter were measured over 3 years in a small-scale replica of the study of the effects of dairy cow grazing management and stocking rate reported by McMeekan & Walshe (1963).

2. The four treatments were

(i) Controlled rotational grazing, light stocking rate (0.95 cows/acre).

(ii) Controlled rotational grazing, heavy stocking rate (1.19 cows/acre).

(iii) Uncontrolled, set stocked grazing, light stocking rate (0.95 cows/acre).

(iv) Uncontrolled, set stocked grazing, heavy stocking rate (1.19 cows/acre).

3. The pasture measurement technique employed measured net pasture production (gains through new growth minus losses from all sources). It is argued that this parameter, rather than absolute pasture production, governs the changes in the dry matter feed supply to the grazing animal.

1. Dry-matter intake, pasture utilization and grazing pressure were studied over 3 years on a small-scale replica of a dairy cow grazing management x stocking rate trial.

2. The four treatments were:

(i) Controlled rotational grazing, light stocking rate (0.95 cow/acre).

(ii) Controlled rotational grazing, heavy stocking rate (1.19 cow/acre).

(iii) Uncontrolled, set stocked grazing, light stocking rate (0.95 cow/acre).

(iv) Uncontrolled, set stocked grazing, heavy stocking rate (1.19 cows/acre).

3. Mean D.M. intakes were: (i) 29, (ii) 21, (iii) 28 and (iv) 21 lb./cow per day. D.M. intake was reduced on average by 7 ± 2.1 lb./cow per day at the higher level of stocking.

1. Pasture parameters have been correlated with animal production parameters from a trial in which two management systems (‘controlled’ and ‘uncontrolled’ grazing), each at two stocking rates (0.95 and 1.19 cows/acre), were compared.

2. Per acre butterfat production was positively related to percentage utilization of available D.M., but negatively related to yield of available D.M.

3. Per cow butterfat production was significantly and positively correlated with yield of available D.M. in the two months after calving (August and September) and in the penultimate month of lacta-tion (April), but this correlation was not significant in other months.

4. It is concluded that management system was as important as stocking rate in increasing the utilization of pasture and animal production from pasture.

Several town-refuse manures were compared with farmyard manure at Rothamsted and five other places between 1940 and 1947. The organic manures were used at 8 and 16 tons/acre with and without fertilizer nitrogen and potash. Direct and residual effects were measured on agricultural and horticultural crops.

All organic manures improved yields in the year of application, FYM most and consistently. The average percentage increases in yield produced by the pulverized refuses tested, in relation to the increase from an equal weight of FYM, were: sugar beet 22, mangolds 83, carrots, 85, potatoes 51. The corresponding figures for screened dust were: sugar beet 40, mangolds 28, carrots 41; the dust slightly depressed potato yields. Averaging all sixteen experiments on root crops, the pulverized refuses had 64% of the first-year effect of FYM and the screened dust 25%.

The yields of seed from a hybrid, one of its parents and different mixtures of the hybrid and parent were compared in the case of two different hybrids. Open-pollinated controls were included in the trial, which was sown at about the normal rate for beans. With both hybrids a mixture of 11 of hybrid to 1 of parent yielded as well as the hybrid itself and mixtures of 2 of hybrid to 1 of parent yielded in both cases about 7 cwt./acro more than the mean of the open-pollinated controls. With the higher-yielding hybrid, which had less contrast in vegetative vigour between hybrid and parent, mixtures in the proportions 5:1 and 2:1 showed declining yields, but with the other hybrid they yielded as well as the pure hybrid.

Dinoseb and TCA were successfully used to control weeds in potatoes by Robertson (1960), and Wood, Sutherland & Stephens (1960). Since then many investigations have been carried out on the use of newer herbicides including the bipyridils, triazines and substituted ureas. The results of a number of these studies, presented at the Seventh British Weed Control Conference (1964), suggested that herbicides might give effective control of annual weeds in potatoes under a range of British conditions. Yields of marketable ware following herbicide treatment were similar, in general, to those obtained following standard post-planting cultivations, but occasionally the yields after herbicide treatment were either as much as 20% higher or lower than the controls. The performance of the herbicides was related mainly to weed flora, soil type and amount and distribution of rainfall.

A study was made of phenotypic correlations between seed yield and some other traits of determinable value in two bred varieties of meadow fescue. Seed yield and such characters as time of flowering, plant height and dry-matter production of spaced plants in October and at the time of anthesis were found to be closely associated.

The method of path coefficient analysis was used to study the interrelationships of seed yield and its components in the causal system: fertile tiller and floret numbers, percentage fertility and thousandseed weight. This analysis corroborates the result of simple correlations in showing the importance of fertile tiller numbers and fertility as major determinants of seed yield.

During 1962-65 investigation was carried out at Cambridge on the effect of irrigation combined with cutting treatments on vegetative growth, inflorescence formation and yield of seed of S184 white clover sown on gravelly loam of poor waterholding capacity.

Under the conditions described, irrigation was beneficial for seed production when it was applied between the period of shutting-up and the start of clover flowering. An excess of water either from natural precipitation or irrigation during the flowering period had, however, a harmful effect on seed production.

Apart from the first year, the effect of differential cuttings up to the early bud stage was insignificant on the seed yield. The interaction cutting x irrigation was not significant.

The author is grateful to Mr F. R. Home, Director of the National Institute of Agricultural Botany, for opportunities and facilities provided for this experiment.

Yellow rust of barley has been observed more frequently at Cambridge in the period 1960-65 than the previous five years. The disease occurs in most parts of England but appears to be prevalent and more damaging in the south and west of the country. The increased incidence of the disease is probably associated both with the greatly increased acreage of barley now being grown and with the introduction of more susceptible barley varieties.

Two isolates of Puccinia striiformis differing in virulence characteristics have been found to be representative of the population of the pathogen in England. These isolates are similar to, if not identical with, physiologic races 23 and 24 which are widespread in continental Europe.

A survey of the seedling resistance to P. striiformis of the currently cultivated barley varieties showed that, of the twelve varieties tested, nine were susceptible to both isolates of the pathogen and three were susceptible to one isolate and resistant to the other. No varieties were resistant to both isolates.

Field experiments were done at Rothamsted each year from 1940 to 1948 to compare arange of organic manures with farmyard manure and with fertilizers. Eight kinds of farmyard manure (FYM) made under controlled conditions from the same quantity of feedingstuffs, sewage sludges from 7 sources, composts of sewage sludge with straw from 4 sources, 5 types of town refuse, cut-bracken stacked over winter, and peat, were tested on potatoes at single and double dressings. All organic manures were compared with and without fertilizers supplying 0.6 cwt. N, 0.6 cwt.P2O5and 1.0 cwt. K2O. The soils were heavy loams, farmed in normal rotations; a fresh field was used each year. Residual effects were measured on cereals grown in the year after the potatoes.

1. The availability of K in potassium metaphosphate was investigated in an experiment with large pots using a red sandy soil, low in exchangeable potassium. Potatoes were grown. The effects of potassium metaphosphate in three different granule sizes, applied at two rates, were compared with those of equivalent potassium chloride and potassium sulphate.

2. Characteristic deficiency symptoms appeared in plants receiving no K and the crop responded to K fertilizer in potassium concentration, yields of tubers, and dry matter, and starch concentrations.

3. Potassium metaphosphate, regardless of granule size and of application rate, was as effective as potassium chloride and potassium sulphate in giving normal development of potato plants, high potassium uptake in the foliage, and yield of tubers.