The most important harvested organs of crop plants, such as seeds, tubers and fruits, are often described as assimilate sinks. They play little or no part in the fixation of carbon through the production of sugars through photosynthesis, or in the uptake of nitrogen and sulphur, but import these assimilated resources to support metabolism and to store them in the form of starch, oils and proteins. Wild plants store resources in seeds and tubers to later support an emergent young plant. Cultivated crops are effectively storing resources to provide us with food and many have been bred to accumulate much more than would be required otherwise. For example, approximately 80% of a cultivated potato plant's dry weight is contained in its tubers, ten times the proportion in the tubers of its wild relatives (Inoue & Tanaka 1978). Cultivation and breeding has brought about a shift in the partitioning of carbon and nitrogen assimilate between the organs of the plant.

Carcass measurements including chemical composition and specific gravity data from 40 male and 40 female quails killed at 42 days of age were evaluated for use as an indirect means of estimating carcass fat. The results indicated that carcass fat was highly negative correlated to water (r = —0·93 and —0·87 for males and females, respectively) and that the inclusion of carcass protein improved the accuracy of prediction a little (r = -0·93 and -0·88). Carcass fat was only moderately related to specific gravity (r = —0·55 and —0·42) and the reliability as estimator of carcass fat was less than water or protein. Also, body weight was positively related to carcass fat (r = 0·71 and 0·42).

1. Twelve experiments were carried out in Bedfordshire and Hertfordshire in 1955–57 to compare combine-drilling and broadcasting muriate of potash for barley. Ordinary mineral soils were used and only one contained more than 25% of calcium carbonate.

2. On average of all the experiments in each year 0·25 cwt. K2O/acre drilled with the seed gave higher yields than 0·5 cwt. K2O/acre broadcast and worked into the seedbed. The average extra yields of barley from combine-drilling, as compared with broadcasting, were 1·2 cwt./acre when 0·25 cwt. K2O/acre was applied and 2·0 cwt./acre of grain when twice as much K2O was given. In twenty-one of the total of twenty-four comparisons drilling gave higher yields than broadcasting and in onethird of these comparisons the effects were significant. Combine-drilling gave higher average yields of straw than broadcasting.

3. The average level of response was not great, the low and high rates of combine-drilled muriate of potash increasing yields by 13 and 16%, respectively. Only a small proportion of the applied potassium was taken up by the crops; apparent recoveries by grain plus straw averaged 11% of the light-drilled dressing and 8% of the heavy dressing.

4. The level of response to potassium varied from year to year, but was much greater on average in the 1955 experiments than in 1956 and 1957. There was no close relationship between the degree of response and values for dilute hydrochloric-acidsoluble potassium or exchangeable potassium in the soils used.

Growth and efficiencies of nitrogen and energy utilization for growth by 72 young British Friesian steers (initial live weight (LW) 110 kg) offered a well preserved, formic acid-treated, perennial ryegrass silage with and without supplements of fish meal were examined. Silage was offered either alone or mixed with 50, 100 or 150 g fish meal/kg silage dry matter (DM) and each diet was offered either ad libitum or intakes were restricted to 16, 19 or 22 g dietary DM/kg LW/day. Treatments were imposed over a period of 132 days. Body component weight gains were determined by comparative slaughter.

Increasing the level of either feeding or fish meal increased rates of empty body weight gain linearly (P<0·001) and curvilinearly (P<0·05) respectively. Fish-meal supplementation increased rates of ash and crude protein gain (P<0·001) but, in comparison with the curvilinear response to increasing level of feeding (P<0·001), had small linear effects on fat gain (P>0·01). Consequently, in terms of whole body composition, animals given fish meal were leaner than animals offered silage alone. Fish-meal supplementation had no significant effect on the composition of the carcass but increased the concentration of protein in the liver and gastrointestinal tract.

The increase in nitrogen intake associated with feeding fish meal resulted in a reduction in the efficiency of nitrogen utilization as level of fish meal increased. Nitrogen intake required for maintenance was estimated to be 1·054 g/kg LW0·75. In spite of marked differences in the composition of the empty body-weight gain, there was no evidence to support an effect of fish meal on the efficiency of metabolizable energy (ME) utilization for growth (kf) which was estimated to be 0·346 on the basis of data scaled by LW0·75. ME intake required for maintenance (MEm) was estimated to be 0·536 and 0·502 MJ/kg LW0·75 for silage alone and the 150 g fish-meal level respectively.

It is generally recognised that the study of arid soils frequently necessitates sampling to a depth of 6 feet or more. The most satisfactory way of doing this is to dig a pit and take samples from a vertical face. This method is obviously unsuitable for the examination of small plots and some kind of boring tool must be used instead. In the tenacious clay soil of this area hand augers have been tried without success, but the mechanical difficulties involved have been largely overcome by use of the apparatus illustrated, which (a) secures a truly vertical bore, (b) resolves the thrust into two components.

The limitations of the “constant” saturation capacity as a factor in the characterisation of types of soils, rather than individual soils, are discussed. An attempt has been made to overcome these limitations by distinguishing between the contributions made to saturation capacity by the organic and inorganic colloidal components of three widely different tropical soil types.

1. Numerical evidence is given which shows that saturation capacity is very closely related to the content of clay and organic matter of soil (irrespective of the proportions in which they are present), but not to the fine silt fraction. Nevertheless, the correlation between saturation capacity and (a) organic matter, and (b) clay, is significantly greater for the tropical type containing the smallest amounts of these components than for the type containing the largest amounts.

Bean plants (Phaseolus vulgaris L.) were grown in field plots with the objective of comparing the effect of some soil amendments on sodium uptake and translocation at three levels of salinity in the soil.

Gypsum and wheat straw mulch treatments reduced the translocation of sodium from the roots to the stems and leaves at the higher external sodium level. Incorporation of animal manure with the soil had little effect on translocation at the higher level but may have promoted sodium translocation to the stems at the lower level.

Plant growth and survival were negatively correlated with the sodium content in the plant, particularly with that of the stems.

Using data (1950–64) from the government-owned herd of Jamaica Hope cattle at Bodles, Jamaica, it was estimated that the fraction of cows called on the basis of their milk production in any given lactation was of the order 0·00 to 0·05. Using data (1967–68) from ten high–and ten low-producing farmer herds of the same breed, it was found that the level of calling was low and that cows proceeding from one lactation to the next had a yield superiority over the total population of only + 4 gallons. It is suggested that one of the principal reasons for the apparent lack of response to selection in dairy herds in the tropics may be that little or no selection for production is in fact practised.

Early stages in the development of reproductive tillers of cocksfoot were studied in uncut swards, and in regrowth after cuts taken at a critical stage.

In uncut swards, initial stages of stem extension (up to 10 cm) occurred over 3 weeks. During this period the last three or four leaves initiated on the tiller became visible externally. Tillers with stems of less than 2 cm generally had one or two partially emerged blades. Those with stems 2–6 cm long carried two, three or, occasionally, four partially emerged blades; the sheaths of two, and sometimes three of these leaves extended beyond the stem apex. Hence, for tillers with 2–6 cm stems, even lenient defoliation involving the removal of only one expanded blade would result in the severance of a further two, three or four developing leaves; at an earlier stage only one or two developing leaves would be severed.

In the regrowth studies it was found that defoliation of reproductive tillers whose apices were below cutting height and which, at the time of cutting, had stems of up to 8 cm, led to contrasting effects: some made only negligible regrowth, whilst others made rapid extension growth. Some of the most rapidly extending tillers retained no leaf blades, and therefore the alternative effects of defoliation cannot be completely explained in terms of leaf retention. Other possible mechanisms contributing to these effects are discussed.

The organic-matter intake and the digestibility of grazed tropical pasture mixtures were assessed by the chromic oxide-faecal organic matter-nitrogen technique in five digestion trials. The pasture treatments were designated as: H, Cynodon nlemfuensis var. robustus in a mixture with the legumes Centrosema pubescens and Stylosanthes gracilis; J, Pennisetum purpureum in a mixture with the two legumes in H; K, treatment J plus Panicum maximum; L, a mixture of all the grass and legume species in treatments H, J and K.

The mean organic-matter digestibility of the herbages was determined in indoor digestion trials during the experimental period and varied from approximately 60·0 ± 1·73% to 62·7 ± 4·18% in treatments K and H respectively, with treatments J and L falling between these two values. The mean digestibility of the herbage as grazed, however, was approximately 66·8 ± 1·72, 69·7 ±7·68, 67·1 ± 4·40 and 67·4 ± 4·15 % for treatments, H, J, K and L respectively.

The estimated mean intake of organic matter was somewhat lower, while that of the digestible organic matter was appreciably lower than those reported for animals of corresponding live weights in temperate countries. Grazed pastures were better digested by 4·1 digestibility units in treatment H, by 7·1 in both J and K, and by 5·3 units in L, compared with the indoor digestion trials.

More intensive studies are still needed to warrant any justifiable conclusion as to whether the low intake of herbage by tropical cattle is due primarily to the high crude fibre and the low nutritional values of the pastures, or to the inherent capacity of the animals conditioned to grazing poor·quality pastures.

The extent of the change in pH on incubation, when bull sperm were suspended in various fluids of different composition, was affected by the buffer capacity, the pH, and the glucose content. In one such fluid, used to replace seminal fluid, there was a highly significant positive correlation between the pH. change and the number and motility of the sperm, and between the pH change in this fluid and in undiluted semen. The various conditions which appear to affect the increase in acidity are discussed, and it is concluded that there is no practical object in determining the change in pH on incubation in an artificial fluid of uniform and constant composition, instead of in semen.

Sulphur content, expressed as a percentage of clean dry wool weight, was measured at monthly intervals in two breeds of sheep, Cheviot and Merino x Cheviot backcross (¾ Merino, ¼ Cheviot), offered an equivalent annual amount of feed in three ways—constant level, natural grazing cycle and reversed grazing cycle. The relationships between S content and wool growth rate or nutrient intake differed with both breed and nutrient cycle, but all the results could be explained satisfactorily on the basis of a constant optimum composition for each individual with sulphur impoverishment related to lack of balance between follicle activity rate and high-S substrate availability.

The difference in mean maximum S content between breeds (3·87% and 3·81% for Cheviot and ‘Merino’ respectively) was much smaller than the difference between individuals within the breeds (4·05·3·72% and 3·92·3·66%). The seasonal depression within individuals varied with nutrition and wool growth rate, Cheviot sheep showing the greatest depression and lowest values (2·89 and 3·28% for Cheviot and 'Merino, respectively in the reversed cycle group). There was no consistent seasonal trend in the relationship between clean and unscoured wool weight.

Growing conditions and testing methods were varied to investigate the use of the Pelshenke test in breeding wheat varieties for good bread-making quality in the United Kingdom. Varieties of winter wheat representing a range of bread-making quality were consistently differentiated. Fresh compressed yeast gave greater varietal differences than did dried yeast but kneading time and grain moisture content were not critical. The values obtained were relatively insensitive to the early stages of germination, to the addition of α-amylase and to variation in grain protein content resulting from N fertilization and irrigation. Thus it appears that the Pelshenke test mainly reflects gluten quality, rather than the whole complex of characters which are integrated by baking tests, and the ranking of the varieties is sufficiently independent of environmental conditions to be of considerable value for selection of early generation breeding material.

1. The Awassi ewes reached an average live weight of 45 kg at two years of age and a mature weight of 57 kg at four years of age.

2. The average yearly production of grease wool has been 2·2 kg.

3. When rams were kept with the flock throughout the year approximately 60% of the lambings occurred during January–February. It declined rapidly during the following months and no lambs were born in July–August.

4. Single lambs had an average birth weight of 4·6 kg for males and 4·3 for females. Twin lambs were about 20% lighter than singles. The corresponding weaning weight at two months of age was 17·9 and 16·8 for singles and 13·4 and 12·4 for twins.

5. The twinning rate increased from 5% at first lambing to 30–35% at 6th lambing, when the ewes were about seven years old.

An interesting factor governing the nitrate content of a soil has been brought out in the course of the preceding work on the treatment of soil with volatile compounds.

Two sets of experiments were conducted on oxic Plinthustalf and udic Ustochrept soils in 1983–85 at Ouagadougou, Burkina Faso. One set tested six daylength-insensitive (DI) cultivars and the other set compared four or five daylength-sensitive (DS) cultivars with one or two DI cultivars as controls, sown on three or four dates. Sowing date, cultivar and their interaction significantly affected seed yield in 1983 and 1985. In 1984, yield was not affected by sowing date in the DI cultivars nor by the sowing date x cultivar interaction in the DS cultivars. Optimum sowing dates were mid- and late July. Sowing earlier gave no yield advantage, whereas sowing later reduced yield severely.

The medium-maturing DI cultivar TN88–63 and the DS cultivar Koakin Local, which has a critical photoperiod in late August, exhibited average to below average yield stability but had a high mean yield and were considered well adapted in all conditions. The other cultivars were either moderately or poorly adapted to the Sudan savannah zone. The sowing date experiments were effective in identifying adapted cowpea cultivars, even from a single year's data, and can be used for screening cowpea for adaptation in the Sudan savannah zone.

1. Symptoms of copper deficiency and toxicity were studied in guar, bottle gourd, eggplant and blue panic grass using sand culture technique.

2. The visual deficiency symptoms are: curling of the young leaves along the margins, chlorosis of the leaflets, necrotic spots on the leaves and drying of very young leaves in guar; loss of turgidity and drooping of lower leaves followed by chlorosis and drying of leaves in bottle gourd; faint green colour of the leaves, chlorosis of the outer rim of the older leaves, white necrotic spots and leaf scorch in eggplant; yellowish green colour of leaves, brownish white spots and depressed growth in blue panic grass.

3. The toxicity symptoms are: stunted growth, drying of the lower leaves and formation of few seedless pods in guar; chlorosis of the lower leaves and marked stunted growth in bottle gourd; dull green colour and chlorosis of the leaves in eggplant; stunted growth, leaf chlorosis and burning appearance of the plant in blue panic grass.

4. There is an increase in copper uptake with increase in the rates of application of copper.

5. There is a decrease in. the molybdenum content with increase in copper applications indicating the inverse copper-molybdenum relationship.

The voluntary food intake, in vivo digestibility and site of nutrient digestion was measured in 12 Polled Dorset ram lambs, from 6 to 24 weeks of age, offered clover hay. Lambs were weaned at 6 weeks of age. Six were fitted with a permanent T-shaped cannula in the abomasum and a temporary rumen catheter during the periods of digesta flow measurement.

Surgical modification of lambs did not influence intake (g/kg live weight (W) per day), in vivo digestibility or marker retention time in the rumen. However, intact lambs grew significantly faster than cannulated lambs (139 v. 109g/day, P < 0·05) apparently because of an overall higher cumulative intake over the whole experimental period rather than any change in efficiency of use of nutrients or maintenance requirement.

Relative to live weight, intake increased rapidly until c. 10 weeks of age and remained relatively constant at c. 37 g DM/kg W per day for the remainder of the experiment. Age had no effect on in vivo digestibility of organic matter (OM) or neutral detergent fibre (NDF) (average 0·69).

The proportion of digestible organic matter apparently digested in the rumen (DOMADR) decreased from 0·63 to 0·47 between 8 and 24 weeks of age whilst intake between these measurement periods increased. Nonammonia N (NAN) flow past the abomasum was similar at all ages in relation to digestible organic matter intake (55·1 g NAN/kg DOMI) but was higher at 16 and 24 weeks of age than at 8 and 12 weeks of age, respectively, in relation to organic matter apparently digested in the rumen (OMADR) (116 and 85 g NAN/kg OMADR, respectively, P < 0·05).

Fractional outflow rate of digesta markers from the rumen, when estimated from abomasal digesta, was significantly higher than when estimated from faeces (103Ru-p 0·121 v. 0·09; 51Cr-EDTA 0·169 v. 0·111/h; P > 0·05).

It was concluded that cannulation did not affect intake and digestion characteristics in these young lambs. The changes in the site of nutrient digestion as the animals aged may have been due to agerelated changes in digestive function but appeared to be associated with the increase in intake that occurred between measurement periods of the cannulated lambs.

The use of repeated measures analysis of variance (ANOVA) options for the analysis of in vitro ruminal fermentation gas production profiles is illustrated. Because of the different variances and covariance structures among profile observations, ordinary ANOVA for more than two-time points is not recommended. To mitigate this problem, the Greenhouse–Geisser epsilon correction can be applied to reduce the degrees of freedom, inflated by violation of the sphericity assumption, for F ratio probability calculations. After this correction, the Box–Greenhouse–Geisser ANOVA (modified ANOVA) layout appears similar to the layout of a split-plot design ANOVA with whole plots divided into subplots (incubation time). Any F tests in the main plot part are valid but F tests involving the time factor from the subplot part need modification because time factor, by its very nature, cannot be allocated at random. Application of multivariate ANOVA, distance multivariate ANOVA, ante-dependence and mixed model analysis are also considered. All these options lend themselves to wide application in the applied biological sciences.