Water influx, i.e. total water intake from water drunk and water obtained from food, was measured using tritiated water in six groups, each containing ten single comb White Leghorn (SCWL) hens, in which each group received decreasing amounts of dry matter (D.M.) in decrements of 10%. Group 1 received 101·2 g D.M./day, an amount normally offered these hens, group 2 received 92·4 g D.M./day, group 3 received 81·0 g D.M./day, group 4 received 70·4 g D.M./day, group 5 received 61·6 g D.M./day and group 6 received 52·8 g D.M./day. In the first 4 weeks, egg production remained relatively high in the restricted fed groups compared with group 1 and body mass declined rapidly (period I); in the second 4 weeks, egg production declined to a great extent but body mass remained constant (period II). The ratio of water influx to DMI remained constant in the two periods in hens with the same DMI but with different egg production. The linear regression of DMI and/or egg production on water influx were significant within each period. DMI explained 65% of the variation in water influx, egg production explained 30/55% of the variation, and both DMI and egg production explained 66/70% of the variation. Within each period, the regressions of DMI on water influx in hens with similar egg production were generally significant, and, in contrast, the regressions of egg production on water influx within each DMI were generally not significant. It was concluded that DMI was more important than egg production in affecting water influx in laying SCWL hens.

The Thompson model (Thompson et al., in press), a heat balance model for cattle, was evaluated for Bos indicus and B. taurus under different climate conditions through the use of two local and one global sensitivity analyses and tested against independent datasets. The local analyses, which evaluate the individual effects of parameters on model output, showed that the vasodilation/vasoconstriction parameter and reference body temperature (Tbref) strongly affected body temperature. The global analysis, which evaluates the overall effect of parameters on model output, showed that 6 out of 24 parameters account for 0·79–0·89 of the model variation. The high proportion of variation accounted for by the parameters demonstrates that the model is linear in its parameters, with little interaction between the parameters.

The Thompson model was tested against four independent datasets which included both B. indicus and B. taurus animals. The prediction of the relationship between skin and body temperature from the model aligned closely with the relationship in the datasets (R2 ranged from 0·55 to 0·87, mean bias ranged from 0·32 to 1·49). The prediction of sweating and respiration rates from the model aligned closely with the rates measured in the datasets (R2 ranged from 0·80 to 0·98 and 0·79 to 0·93, respectively). The delay in the diurnal body temperature variation, relative to air temperature, was more accurately predicted for cattle in the sun than for cattle in climate chambers. Given the limited datasets for construction and parameterization (both of which are described in Thompson et al., in press), the model evaluated in the current study performed relatively well compared to the literature and known biology.

The sedimentation method for the mechanical analysis of poly-disperse systems such as a suspension of soil in water is now in its various modifications a well-established technique of analysis(1). Unfortunately, they all, with one exception, involve interference of some kind with the process of sedimentation itself; either by the introduction of pipettes and hydrometers, or the opening of drain-cocks, and the one exception, viz. the sedimentation balance, is subject to a considerable error of a different kind (2). The present paper describes the results of attempts to use the transmission of a beam of light through a glass cell, as a measure of the sedimentation process taking place within it, the transmitted light being received on a photo-electric cell.

1. An experiment designed to investigate the effects of heavy dressings of nitrogen, inter-row distance and ‘method’ of sowing on the yield of a lucerne-cocksfoot ley is described and the results discussed.

Two winter wheat (Triticum aestivum L.) cultivars, Jimai20 and Shannong12, differing in phosphorus (P) utilization efficiency, were selected to study the effect of P application rate on changes in glutenin macropolymer (GMP) size distribution and the content of high-molecular-weight glutenin subunits (HMW-GS) in wheat grain. Four P levels (0, 40, 100 and 160 kg/ha) were applied under N1 (112·5 kg/ha) and N2 (225 kg/ha) conditions in the field, in 2008/09 and 2009/10. The results showed that increased P levels favoured HMW-GS synthesis under N1 conditions, but had a less pronounced effect under N2. When compared with the control, the volume proportions of <10 μm GMP particles in grains of both cultivars were significantly decreased, and those of >100 μm were increased in response to P application. The volume proportions of 10–100 μm GMP particles in the cultivars Jimai20 and Shannong12 were respectively lower and higher in response to P application than with no P fertilizer. At maturity, for both cultivars, total HMW-GS content was negatively correlated with GMP particle volume of <10 μm, but positively correlated with that of >100 μm. These observations suggest that both P and N affect protein synthesis in wheat grains and there exists a relationship between HMW-GS content and the synthesis of large GMP particles (>100 μm). The N×P interaction was the most important factor to regulate the HMW-GS and GMP contents.

Grafting of fresh cuttings using drought-susceptible and low-yielding clones as scions on drought-tolerant clones as rootstocks offers the possibility of raising composite plants with improved productivity and drought tolerance. Hence, the study was aimed to widen the choice of compatible composites and to delineate the underlying factors responsible for productivity and drought tolerance in grafted plants. One year-old composite plants of TRF-1, TRF-2 and UPASI-28 cleft-grafted on the rootstocks of UPASI-2, UPASI-9, ATK-1 and TRI-2025 were field planted along with their respective controls and evaluated. The results indicated that productivity and drought tolerance of scion clones varied significantly with the rootstocks used. Significant increases in yield and yield components were noted in the following graft combinations compared with their corresponding self-rooted scion clones: TRF-1 grafted on UPASI-9 and ATK-1, TRF-2 grafted on all four rootstocks, and UPASI-28 grafted on UPASI-9, TRI-2025 and UPASI-2. The findings clearly emphasize the scion–rootstock interaction as the critical determinant of productivity in grafted plants compared with vigour, drought tolerance and yield potential of scion and rootstock clones. Further, high-yielding capacity of grafts over the ungrafted scions and rootstocks was largely dependent on the yield potential of the scion clone and the degree of scion–rootstock compatibility. Higher field survival and enhanced yield observed during the drought period in the compatible grafts demonstrated their better drought tolerance compared with their respective self-rooted scions.

1. A series of three experiments were performed to examine grass as a food for dairy heifers.

2. Indoor feeding resulted in lower intakes of herbage and slower growth but gave greater outputs per acre of animal days and live-weight gain than grazing.

3. The maximum consumption and growth rate, obtained on young grass, were 2·84 lb. herbage dry matter per 100 lb. live weight per day and 2·2 lb. live-weight gain per day for grazing stock. The corresponding figures for indoor feeding were 2·49 lb. herbage dry matter per 100 lb. per day and 1·34 lb. live weight gain per day.

4. Live-weight gain per day was linearly related to herbage dry matter intake from 1·48 to 2·48 lb./ 100 lb. live weight/day.

5. Intake of herbage and growth rate only fell after the herbage came into full flower.

6. Increased stocking rate had small effects on growth rate because the animals grazed the paddocks more heavily.

7. 2·6–3·0 lb. grass dry matter offered per 100 lb. live weight per day was judged an adequate ration for yearling heifers. This gave growth rates of 1·60 lb./day on herbage up to the flowering stage and a consumption of 88% of the available herbage.

8. As an experimental technique zero grazing was found inadequate to replace grazing since it fails to reproduce similar intakes and rates of production. It permitted the reduction of intake to sufficiently low levels that live-weight gain per animal and per acre were reduced.

9. The greatest output per acre was found to occur between limits of intake per day of 1·8–2·4 lb. herbage dry matter per 100 lb. live weight. Above the point of maximum output per acre level of feeding had little effect on production per animal and rate of stocking controlled output per acre. Below this point level of feeding controlled production per animal. The case is advanced that these latter levels of feeding are necessary in grassland experiments.

In 1989 and 1990, small, medium and large seed tubers, cv. Désirée, were planted 38 cm apart in experiments designed to measure the effects of different combinations of neighbouring plants on the yield and size of tubers from individual plants. Total yield, ware yield (> 150 g), numbers of tubers and numbers of stems increased as seed tuber size increased. Also, decreasing the size of seed tubers decreased the numbers of tubers in all sizes except those > 200 g. Competition from the two neighbouring plants on either side in the same row (first neighbours) increased as the size of seed tubers increased and with all seed sizes yields decreased. For example, plants from large seed benefited from small seed planted as neighbours whereas, with plants from small seed, yield was decreased with neighbouring plants from large seed. Numbers of stems and tubers were not affected by neighbouring plants. Also yields were not affected by the two plants adjacent to the first neighbours (second neighbours) or by the size of seed tubers planted in adjacent rows. Competition from first neighbours also affected tuber size distributions and, with small seed, increasing the competition decreased the number of tubers > 150 g and increased numbers < 50 g. Medium and small seed planted as neighbours of large seed increased numbers of tubers > 150 g. When yields from plants produced by seed of each size with similarly sized seed planted as first neighbours (uniform populations) were compared with mixed populations, yields were always greater from the mixed populations of different seed sizes planted alternately than from the means of uniform populations. Therefore in the mixed populations, there were larger gains from the larger seed than losses from the smaller seed.

Though it is neither customary nor perhaps desirable to utilise sugar beet for feeding purposes, it is conceivable that circumstances might arise occasionally when a farmer would be desirous of feeding the whole or part of his beet crop. This is indicated by the fact that enquiries as to the value of sugar beet for pigs are received from time to time. During the carrying out of the investigation into the value for pigs of dried sugar-beet pulp and molasses-sugar beet pulp, an account of which work is given in this issue of the Journal (1), the opportunity was taken of making a similar study of whole sugar beet. A dual investigation was made, consisting of a digestion trial under the conditions of the metabolism room and a large-scale feeding trial under ordinary farm conditions. It was hoped that the evidence from this twofold line of enquiry would not only settle the question of the value of sugar beet in the feeding of pigs, but also throw light on the subject of the value of root crops in general for swine.

The problem of the use of water by cultivated plants during the period of their growth is of great scientific interest. It is certainly of prime interest for the farmers of a dry region where to secure a yield everything depends in most cases upon the problem of moisture.

When studying the problem of the use of water by cultivated plants under field conditions the importance of extremely unstable and widely varying meteorological factors is evident. The fluctuations are especially large and irregular with respect to moisture.

The fluctuation in the nitrate content of arable soils in southern Australia is of special significance in connection with the practice of bare fallowing as a preparation for wheat growing. In the wheat areas of Western Australia, South Australia, Victoria and the southern districts of New South Wales, fallowing is the recognised cultural basis for successful wheat production, and from a purely mechanical point of view the practice in the hands of the more skilful farmers has probably reached a degree of perfection which it would be difficult to surpass.

Near-infrared spectroscopy (NIRS) was used to analyse the crude protein content of dried and milled samples of wheat and to discriminate samples according to their stage of growth. A calibration set of 72 samples from three growth stages of wheat (tillering, heading and harvest) and a validation set of 28 samples was collected for this purpose. Principal components analysis (PCA) of the calibration set discriminated groups of samples according to the growth stage of the wheat. Based on these differences, a classification procedure (SIMCA) showed a very accurate classification of the validation set samples: all of them were successfully classified in each group using this procedure when both the residual and the leverage were used in the classification criteria. Looking only at the residuals all the samples were also correctly classified except one of tillering stage that was assigned to both tillering and heading stages. Finally, the determination of the crude protein content of these samples was considered in two ways: building up a global model for all the growth stages, and building up local models for each stage, separately. The best prediction results for crude protein were obtained using a global model for samples in the two first growth stages (tillering and heading), and using a local model for the harvest stage samples.

1. The changes in the sheep population and in the sales of fat sheep have been examined for the West Wales region for the period 1940–8. These changes consist of a gradual annual decline in sales, whilst the severity of the 1947 winter conditions brought about a rapid drop in both sales and population by nearly 33% from 1946 to 1947.

2. Analyses of sales of the four categories of fat sheep—rams, ewes, sheep and lambs—throughout the twenty-five collecting centres have been completed for the 4 years, 1943–6. These showed that lambs accounted for 85% of the fat sheep sales in this region.

3. It was found that the average estimated dressed carcass weight (e.d.w.) of the four categories of sheep (rams, ewes, sheep and lambs) declined gradually from the collecting centres of west Pembrokeshire to the inland centres on the eastern boundaries of the region. This cline is also found in the case of the summer suckling lamb, the autumn wether lamb and the winter-fed fat lamb.

Fertilizer nitrogen recovery under fallow and under a wheat crop (Triticum aestivum L., cv. Miriam) grown on a deep loessial silty loam (Calcixerollic Xerochrept), was studied with 15N labelled KNO3. The labelled nitrogen was applied (at a rate of 180kg/ha) to 30 cm diameter microplots enclosed in hard plastic tubes that protruded 5 cm above the soil surface. In the 1st year of the experiment there was a long dry spell during the main part of the growing season and plant dry-matter yields were low. The 2nd year was wet, with heavy rain early in the season. About one-third of the fertilizer N applied to the fallow was lost from the top 60 cm layer in the 1st year. Most of the fertilizer N remaining in the soil as mineral N at the end of the first season was lost in the 2nd year. The possible reasons for such low N-conservation efficiency are discussed.

Over two years (1984/85 and 1986/87), monthly sampling of shoots of white clover plants compared the populations of white clover in mixed swards at Palmerston North, New Zealand, under set stocking, rotational grazing and a combination of both systems, at a common stocking rate of 22·5 ewe equivalents/ha.

The frequency distributions of shoot (or stolon) dry weight per plant in each population over the study period was described by a log-normal model, which indicated that the populations consisted of many small individuals and few large individuals. Such inequality of shoot dry weight within populations is commonly termed size hierarchy; a statistic giving a measure of such size hierarchy is the Gini coefficient. The populations under different managements had similar Gini coefficients which differed little among seasons or between years. Lack of significant correlation between the Gini coefficient and mean shoot dry weight per plant of each population indicated that, in these white clover populations, size hierarchy was independent of mean plant size.

These results were considered in relation to the clonal growth of white clover in grazed swards and it is suggested that the variable nature of death of older basal stolons makes an important contribution to the variability in size of individual plants and hence to size hierarchy. As size hierarchy, as assessed by Gini coefficients, was relatively stable in these populations over 3½ years, it appears that clonal growth of white clover incorporates sufficient variability within the growth and death processes at the individual plant level to maintain the size hierarchy, irrespective of variations in mean plant size of populations.

1. An examination of carcass reports from two groups of bacon pigs (comprising eleven litters and seventy-five pigs) was made to determine whether the variation in growth rate of normally reared pigs was associated with differences in carcass measurements. The method adopted was to fit orthogonal polynomials to the third degree to the last 10–11 fortnightly weighings converted to logarithms.

2. The residual standard deviation after fitting was about 2–4%. For present purposes, the fitting of second degree parabolae appeared adequate.

The following is a réumé of a physical theory of soil moisture relations developed by the author in 1920 (1). On account of serious typographical and other errors in the original the essential argument is reproduced here together with some observations arising from subsequent work by other authorities.

During a 3-year experimental period (between 1992 and 1995), residual effects on yields of subsequent crops of phosphorus applied either to soyabean or wheat, and on recoveries of the added P and changes in the available P, were studied in a soyabean–wheat cropping system on a typic haplustert very low in available P at Bhopal, India. Phosphorus was applied at rates of 0–52 kg P ha-1 (five treatments) to soyabean and 0–39 kg P ha-1 (three treatments) to wheat during the first year, and in the subsequent years the residual effects were studied in relation to fresh applications of 39 kg P ha-1 to each crop. The yields of soyabean and wheat were increased significantly by the application of P to each crop. Phosphorus applied to soyabean showed residual effects in two succeeding crops, whereas P applied to wheat showed a residual effect in only one succeeding crop. Phosphorus applied to soyabean was more efficiently utilized by the succeeding crops compared to that applied to wheat in the rotation. The recoveries of added P were greater with smaller rates of added P and greater in the first two residual crops. Olsen P in soil was adequate only in the first year and it fell below the critical limit in the subsequent two cycles of cropping. Cumulative P uptake by crops determined the levels of available P in the soil and soil test values declined with increase in cumulative P uptake over time.

Synovex-H®, a combination of testosterone propionate and oestradiol benzoate, was implanted on three occasions at about 90-day intervals into Hereford × Shorthorn (HS), Brahman (B) and BX(B × HS) heifers to try to increase live weights and hence pregnancy rates at first breeding. Half of both the implanted and nonimplanted heifers of each breed was treated every 3 weeks to control cattle ticks and gastro-intestinal helminths. Treatment to control these parasites increased live weights, the increase depending on the breed. Implanting with Synovex-H also increased growth, the magnitude of the increase depending on both breed and treatment to control parasites. When parasites were present in significant numbers in the environment, the implanted groups had higher tick and helminth burdens and, in consequence, their live weight gains in response to the implant were lower than those of the nonimplanted group. The reason for the increase in susceptibility to parasites of the implanted group was not sought. It is suggested that it is associated with the presence, either alone or in combination, of the androgen and oestrogen components of Synovex-H.

By the start of the 10-week breeding season, 290 days after the last dose of Synovex-H was implanted, previous advantages of the implanted groups in live weight had been eroded to the point where the differences between groups were no longer statistically significant. Subsequent fertility both as maidens and as first-calf heifers was generally significantly lower in the previously implanted groups of all breeds. Calves born to implanted heifers were not as heavy as those born to nonimplanted heifers both at weaning and 120 days after weaning. The particular regimen of use of Synovex-H followed in this study cannot be recommended if heifers are to be used for breeding.

Field experiments made for 2 years on a deep vertisol under semi-arid conditions showed that soil-surface evaporation control by mulching with rice straw or transpiration suppression by foliar application of kaolin or atrazine increased the yield of grain sorghum. These materials decreased soil moisture depletion and thus increased water-use efficiency. Application of one irrigation at the boot-leaf stage was beneficial. No additional advantage was noted with two irrigations, one given 45 days after seeding and the other at anthesis.