A wealth of information is available concerning the ‘normal’ gastrointestinal mechanisms within various species of herbivores (Alexander, 1962; Church, 1971; Quarterman, Phillips & Lampkin, 1957). In addition, the effect that dehydration has upon the physiology of digestion has also been investigated (Schmidt-Nielsen et al. 1956; Schmidt-Nielsen, 1964; Maloiy, 1972; Macfarlane et al. 1972). This communication presents preliminary observations on the effect that dehydration hasupon gastrointestinal water content, as a percentage of total gut contents, and fluid osmolality (m-osmol/kg H2O). A comparison was made under controlled laboratory conditions between six species of domestic herbivores fed identical diets and exposed to a simulated desert environment

Water balance components under wheat were assessed by employing two simple models, differing in their structure and data requirements, namely the soil-plant–atmosphere–water (SPAW) model of Saxton (1989) and the water balance model (WBM) of Arora et al. (1987). A few modifications based on the SPAW model procedure for the estimation of green canopy were used in a modified WBM and its performance was also tested. Soil water loss (the sum of interception evaporation, soil evaporation, plant transpiration and deep drainage) from sowing to harvest, simulated with the WBM, modified WBM and the SPAW model, had a close correspondence with the measured sum of profile water depletion, rainfall and irrigation for values ranging between 18·3 and 42·7 cm. Estimates of drainage with the WBM and modified WBM using empirical coefficients were greater than those calculated using the SPAW model for situations where the upward flow of water into the root-zone was negligible. Estimates of soil water evaporation using the WBM and modified WBM were invariably smaller than those using the SPAW model. A comparison of simulated and measured soil water storage and a correlation analysis of simulated transpiration with measured biomass at harvest showed that the performance of the WBM was the most realistic of the three models. However, it requires the input of leaf area index values to infer green canopy for each water supply regime. In the absence of this information, the modified WBM and SPAW models are more useful for assessing water balance components in cropped soils.

The Southdown is a terminal sire breed producing about 205 registered rams for commercial use in Britain each year. It is strongly associated with its native area of Sussex, with an hierarchical breed structure very similar to that of 30 years ago. The number of breeding ewes has declined from 5475 in 1957 to (minimum estimate) 1202 in 1985.

French and New Zealand imports in the last 20 years have resulted in present-day British Southdown breeding rams being, on average, only 76% of British descent. If further importations are to be made, semen from rams without foreign blood should be taken for storage first, in the interests of genetic conservation.

The required production of Southdown rams for commercial purposes is achieved with a rather small population size. It would be misleading to describe the Southdown as a ‘rare breed’ without taking account of its commercial function and breed structure.

This study was established to quantify the uptake of 15N-labelled nitrogen (urea) applied in the first and second years of perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea Schreb.) and browntop (Agrostis capillaris L.) seed crops, and the availability of the residual fertilizer N to a subsequent wheat (Triticum aestivum L.) crop under field conditions in Canterbury, New Zealand. Total recovery of 15N-labelled nitrogen fertilizer was approximately 100% when fertilizer was applied to the grass seed crops in spring. At harvest in year 1, grass straw and seed contained 34–47% and 6–15% of the applied N respectively; 27–35% remained in the soil (0–150 mm depth). Recovery of 15N in straw and soil was higher in fescue and ryegrass than in browntop, but recovery in roots was lower. At harvest in year 2, most of the 15N was present in the soil (30–37%) with only small amounts in the seed (0·7–1·0%), straw (3·6–4·9%) and roots (5·2–12·7%). In year 3, 2·5–3·5% of the residual 15N was recovered in the wheat and 18–26% in soil. Losses of 15N were minimal until ploughing after the second harvest, when there was an apparent loss of 11–35% of the fertilizer N applied. Losses were not directly associated with the fertilizer but indirectly following release of fertilizer N previously immobilized in plant roots and soil microorganisms. Small losses also occurred directly from autumn-applied N, probably through leaching. Despite these losses, overall there was an accumulation of fertilizer N in the soil organic pool, suggesting that ryegrass fescue and browntop seed crops have a role in contributing to the N fertility of the soil.

Meteorological extremes such as heatwaves and water limitations during the ripening season could negatively impact vine ecophysiology and berry metabolism resulting in lower yield per vine. This project aimed to compare two different soil managements during two growing-production seasons (2021 and 2022) with respect to control without any treatment (control). The two managements were: Zeowine (30 t/ha; a soil conditioner made with clinoptilolite and compost proceeding of industrial wine-waste) and compost (20 t/ha). The trial was organized at Col d'Orcia Estate (Montalcino, Tuscan wine region, Italy). The purpose was twofold: (1) to evaluate the effects of Zeowine treatments on leaf gas exchanges, midday stem water potential, chlorophyll fluorescence and leaf temperature (ecophysiology); and (2) to determine any repercussions on the quality of the grapes (technological and phenolics analyses). The parameters plant yield, yeast assimilable nitrogen, fractionation of anthocyanins (cyanidin, delphinidin, malvidin, peonidin and petunidin), caffeic acid, coumaric acid, gallic acid, ferulic acid, kaempferol and quercetin were also analysed. Zeowine showed higher photosynthesis, less negative midday water potential and lower leaf temperature. Essentially, no significant difference was found between the compost and the control. Furthermore, Zeowine grapevines showed higher anthocyanin accumulation and less quercetin content. In general, compost applied together with zeolite could alleviate the adverse effects of water stress and improve plant growth, yield and quality. The control management strategy proved to be the least beneficial for the well-being of the plant and the final quality of the product, confirming the need for amendments in critical years.

The present study examined variation in sowing date on lentils (Lens culinaris) in a standard lentil–barley (Hordeum vulgare) mixed cropping system in the temperate climate of central Europe to determine the effect on crop yield and weed control. A 2-year (2009/10) field experiment was carried out at the organic research station Kleinhohenheim (KH) and at the conventional research station Oberer Lindenhof (OLI) of the University Hohenheim, southwest Germany. The crop was sown at three dates in the period from March to May. Grain yield was significantly higher at the earliest sowing both for lentils (3·0 t/ha at KH, 2·4 t/ha at OLI) and barley (1·2 t/ha at KH, 2·6 t/ha at OLI). Weed biomass at KH increased significantly with delayed sowing and was independent of lentil genotype, whereas sowing date had no significant effect on overall weed biomass production at OLI. Unlike weed biomass, weed density generally decreased significantly with delayed sowing at OLI. The results indicate that early sowing can increase the yield of lentils, and can be used as an indirect method of weed control in some organic farming systems.

Hormonal anabolic compounds are used in certain countries to improve the efficiency of meat production from ruminant animals. The combination of trenbolone acetate (TBA) and oestradiol-17β (OE2) has been shown to be particularly effective in stimulating growth in cattle (e.g. Galbraith & Topps, 1981). These improvements in growth have been associated with increases in nitrogen retention and changes in protein metabolism within the animal. The present study therefore investigated the effect of implantation with TBA + OE2 on the growth and metabolic response of growing steers to alterations in protein nutrition.

The relationship between milk production, blood glucose, blood ketones and free fatty acids (F.F.A.) were studied in lactating Awassi ewes. Increased milk production in ewes was associated with diminished blood glucose and increased serum F.F.A. Clinical cases of ketosis were not observed.

The ewes studied here could be divided into two metabolic populations depending on their blood ketone levels. Those with blood ketone levels of 11 mg % or more, did not show a significant increase in serum F.F.A. or a decrease in blood glucose values with increased milk production. The group of ewes with less than 11 mg % blood ketones showed a significant decrease in blood glucose and a significant increase in serum F.F.A. as milk production increased. Ketonemia of the high ketone group of ewes, was associated with relatively low serum F.F.A. levels. It is suggested that these ketones not originate from depot fat via serum F.F.A. These ketones and/or their precursors, acetic and butyric acids probably participate in caloric homeostasis and are associated with a glucose sparing serum F.F.A. suppressing mechanism.

The suggestion that ketones derived from rumen (R.D.K.) should be distinguished from those derived from adipose tissue (A.D.K.) is discussed.

A pot experiment was made to study the effect of green manuring and iron application on the pE, pH, Fe concentration and iron equilibria in a calcareous and a noncalcareous soil. Green manuring drastically decreased the pE and pH and increased the Fe concentration of the equilibrium soil solution to a greater extent than submergence alone. Addition of Fe decreased pE, pH and increased Fe concentration both with and without green manuring. In calcareous soil pE and pH were high and Fe concentration was low compared with non-calcareous soil. In the absence of green manure and added iron, although there were wide variations in pE, pH and Fe concentration, Fe(OH)3-Fe2+; Fe3(OH)8-Fe2 + and Fe(OH)3-Fe3(OH)8 systems were controlling the solubility of Fe after 1 week of submergence in both the soils. But on green manuring all the above systems in calcareous soil and only Fe(OH)3-Fe3(OH)8 system in non-calcareous soil were operating at 1 week of submergence and continued afterwards. Addition of iron, with and without green manure, failed to bring an appreciable effect on these systems in calcareous and as well as in non-calcareous soil.

The use of environmentally induced genetic male sterile (EGMS) rice could alter the development of hybrid rice from a three-line system to a two-line system. It is critical for the utilization of EGMS rice to determine which are the main environmental factors influencing fertility changes. Fertility responses to photoperiod (P) and temperature (T) were studied in 101 EGMS rice lines under nine controlled regimes combining three photoperiods (15·0, 14·0 and 12·5 h)x three temperatures (30·1, 24·1 and 23·1 °C). According to the variance analysis of seed-setting data, 96% of the total EGMS lines studied could be divided into three types as follows: (1) photoperiod-sensitive genetic male sterility (PGMS) characterized statistically by significant (P < 0·05) P and P × T interaction effects but by a non-significant T effect on fertility, (2) thermosensitive genetic male sterility (TGMS) by a significant T effect, a non-significant P effect and by either a significant or a non-significant P × T interaction effect on fertility, and (3) photo-thermosensitive genetic male sterility (P-TGMS) by only a significant P × T interaction effect on fertility. Among the japonica EGMS lines studied, PGMS, TGMS and P-TGMS accounted for 32·3, 9·7 and 51·6%, respectively. However, among the indica EGMS lines, no PGMS lines were detected and most of them were TGMS or P-TGMS (61·4 and 35·7%, respectively). The results indicate that the selection of indica PGMS lines of rice might be very difficult. The availability of different types of EGMS rice in two-line system hybrid rice is evaluated and the selection of an ideal model of response to photoperiod and temperature for indica EGMS is discussed.

All 53 lettuce cultivars inoculated with cucumber mosaic virus became infected. Leaf mosaic symptoms were generally mild and unreliable for distinguishing degrees of resistance between cultivars. Yield reduction was the most satisfactory criterion for evaluating resistance, with reductions in individual cultivars ranging from 8 to 50%.

Several nitrification inhibitors were compared with nitrapyrin, which was taken as the standard, when injected with aqueous urea into ryegrass leys at Rothamsted during 1977–81 and at Liscombe Experimental Husbandry Farm, Dulverton, Somerset, during 1977–9. Injection was done in either autumn or winter or spring.

All the inhibitors slowed down the rate of nitrate formation from the injected urea. Sodium trithioearbonate (STC) was less effective than nitrapyrin and potassium ethyl xanthate (KEtX) less effective than STC. A mixture of nitrapyrin and carbon disulphide was better than nitrapyrin alone, and a mixture of STO and KEtX was better than STC alone.

At Rothamsted, injecting inhibitors in autumn or winter improved yields and N uptakes, probably because they prevented loss of nitrate N by leaching and perhaps by denitrification. STC, STC-KEtX mixture and etridiazole were as good as, and nitrapyrin–CS2 mixture better than, nitrapyrin alone. Injecting inhibitors in spring frequently decreased yields, perhaps because NH4:NO3 ratios were too large, and increased them only when more than 150 mm of rain fell afterwards.

At Liscombe, where rainfall was higher, but soil temperatures were similar to those at Rothamsted, the benefits from using inhibitors in autumn were larger, but there were none from using them in spring.

Semen from eight Murrah buffalo bulls was collected and analysed for physical and biochemical determinants throughout the year. Depending upon the climatic conditions, the whole year was divided into four periods. The mean values of volume, density, mass motility and sperm concentration was 1·64 + 0·060 ml, 2·48±0·032 (3-point scale), 2·65±0·069 (5-point scale) and 1185 ±19·2 million/ml, respectively. The mean values of alkaline and acid phosphatases were 1238±47·4 and 1244±54·5 King-Armstrong units (KAU)/100 ml of seminal plasma. Average figures for citric acid, calcium, phosphorus, total nitrogen and non-protein nitrogen (NPN) were 507 + 14·1, 53·0±l·2, 121±4·9, 649±12·8 and 116±2·0 mg/100 ml of seminal plasma. Periods of the year had significant effect on volume, alkaline and acid phosphatases, citric acid and NPN (P < 0·01). Different correlations of physical and biochemical determinants are discussed. Of all the determinants only weight of the bull, sperm concentration and NPN were found to be positively correlated with fertility while phosphorus was negatively correlated.

Blood samples were obtained at monthly intervals for 12 months from 8 HK and 8 LK wethers of the Marwari breed maintained at Jodhpur (26° 05′ N, 73° 01′ E). The samples were analysed for packed cell volume (PCV), red blood cell count (RBC), haemoglobin concentration (Hb), mean cell volume (MCV), mean cell haemoglobin concentration (MCHC), plasma inorganic phosphorus and plasma specific conductance.

The HK animals, on average, had significantly higher PCV, RBC, Hb, MCHC and plasma inorganic phosphorus values than the LK animals but the MCV was significantly higher in the LK group. There was no difference in the plasma specific conductance.

PCV, RBC and Hb values differed considerably from animal to animal within each group. These individual variations could help the breed to survive in a desert environment.

No particular tendency or pattern in the effect of season on the blood characters studied has been observed. This indicates that the animals of both groups responded in a similar way to the environmental changes.

When synthetic amino acids are added to an allvegetable diet the amount of nitrogen eliminated in the urine is reduced and the nitrogen retained as tissue protein is correspondingly increased.

The requirements of the weanling pig for essential amino acids have been critically examined, the work involving both growth trials and nitrogenbalance determinations in the metabolism crates.

The addition of synthetic lysine and methionine to a low-protein vegetable diet had a striking effect on the thriftiness of the pigs. It is possible to secure almost as good growth and economy of food conversion on a cereal diet supplemented with as little as 6 % ex. soya-bean meal, when the amino acids are added in appropriate amounts, as is obtained on a similar diet containing sufficient white-fish meal to support maximum growth

Since the year 1927, observations have been made in Victoria on the development of wheat crops of various varieties grown in four different districts of the State.

The method used was based on that employed by Engledow in his “Investigations on Yield in Cereals,” by taking counts on numbers of plants in various “foot length” samples scattered in a systematic manner over the areas studied.

The basis of the observations was the determination of the values which comprise yield, viz. p = numbers of plants, e = ears per plant, n = number of grains per ear, g = average weight of grain.

Data on 841 purebred Bauscat, White Flander, Giza White and Baladi Red litters provided estimates of genetic, phenotypic and environmental parameters for gestation length, litter size at birth and at weaning, mortality and sex ratio at weaning. A total of 170 daughters (paternal half-sisters) of 76 sires were available for the analysis. No important differences were detected among breeds for litter traits studied except litter size at weaning (P < 0·001). Year of kindling affected (P < 0·001) gestation length, litter size at birth and mortality percentage. No clear patterns of the effect of parity and month of kindling on litter traits were observed. The sire of the doe and doe within sire affected most of the traits studied. Estimates of heritability indicated that the sire's genetic contribution to litter traits are much higher during the pre-natal period than for the suckling period. Estimates of repeatability for litter traits studied were relatively low. Genetic and phenotypic correlations between gestation length and other litter traits were relatively low. Litter size traits were positively correlated both genetically and phenotypically. Estimates of genetic and phenotypic correlation between litter size traits and preweaning mortality were generally negative. Phenotypic and environmental correlations were generally very similar in size and sign. Predicted direct selection was shown to give greater improvement in litter size at birth than indirect selection through litter size at weaning.

An experiment was carried out in Northern Ireland in 1994 to examine the effects of ensiling grass on the partitioning of nutrients between lean and fat deposition in lambs using the comparative slaughter technique. The six treatments consisted of: (1) unsupplemented grass silage; (2) grass silage supplemented with concentrates, concentrates constituting 250 g/kg total dry matter intake (DMI); (3) grass silage supplemented with concentrates, concentrates constituting 500 g/kg total DMI; (4) unsupplemented grass which had been conserved by freezing; (5) pre-frozen grass supplemented with concentrates, concentrates constituting 250 g/kg total DMI, and (6) pre-frozen grass supplemented with concentrates, concentrates constituting 500 g/kg total DMI. A total of 84 Dutch Texel×Greyface (Border Leicester×Blackface) lambs, consisting of 42 males which were initially 35 (s.d. 4·8) kg liveweight and 42 females which were 33 (S.D. 2·6) kg liveweight, were used. The silage was well preserved as indicated by its low pH (3·8), low concentration of ammonia (60 g/kg total nitrogen) and high concentration of lactic acid (129 g/kg DM). The grass had a higher pH (5·2) and higher WSC concentration (129 g/kg DM) and lower concentrations of lactic (33 g/kg DM) and acetic acids (6 g/kg DM). Ensiling had no significant effect (P>0·05) on empty body and carcass weight gains. Animals offered unsupplemented silage had significantly lower protein (P<0·001) concentration in the carcass gain and significantly higher lipid and energy (P<0·001) concentrations than animals offered unsupplemented frozen grass. However, there was no effect of forage type on chemical composition of carcass gains when 50% forage was offered. It is concluded that ensiling had no effect on empty body or carcass weight gains, but did increase carcass fatness when unsupplemented forages were offered.

Agronomic research was carried out on upland rice in Toledo District, Belize, in 1979–86, with the objective of improving returns from the traditional system of shifting cultivation and of examining the potential for reducing the demand for new land by cropping for more than one season. The rice was grown in the wet season on land cleared from forest by slash and burn, using a traditional planting technique, placing seed in holes made with a pointed stick.

In a series of fertilizer experiments, in which rice was grown for up to 7 consecutive years, urea and triple superphosphate both increased grain yield, whereas muriate of potash had no effect. Mean yield in the fifth year was 85 % of that in the first. Urea and triple superphosphate both increased the number of full grains/panicle.

A slash and mulch weed control treatment before sowing resulted in low yields of grain in the third year; yield after the use of propanil and 2,4-D (after sowing) was, on average, 77% of the yield after hand weeding; omitting weed control after sowing led to very low yields, particularly in the second and third years.

In the varieties Bluebonnet and C22, grain yield was increased by reducing the distance between stations, particularly where 6, rather than 15, seeds were sown per station. Reducing the distance between stations increased the leaf area index during crop development and the number of panicles/m2, which more than counterbalanced reductions in the number and area of leaf blades per plant, the number of panicles per plant and the number of full grains per panicle. However, the yield/kg of seed sown and per hour spent planting was greatest at the widest spacing. C22 produced more panicles per plant and a greater weight of grain per plant and per hectare than Bluebonnet.

It was concluded that returns from the traditional system can be improved and the demand for new land reduced.

The design and field technique of two large scale experiments, laid down to investigate the problems of sampling and “propinquity”, are described in detail. These experiments were designed so that the plant number, stem number, ear number, straw weight and grain weight for 7200 lengths of 6 in. of drill row, together with the position of each observation, might be obtained.

The lowest sampling error, expressed as a percentage of the mean, is obtained by using the smallest sampling unit, but the large number of sampling units of this size that would have to be taken make it impracticable. The optimum sampling unit consists of 6 ft. of drill row, taken as 3 ft. of two adjacent rows. The size of the sampling unit is of greater importance than the shape in determining its accuracy, and little s lost by using sampling units of 18 in. of five adjacent rows.

The nature of the observation affects the degree of sampling. In the experiments examined the plant number, stem number and ear number require very similar sampling, but grain weight requires a sample which is about twice as large as that required by the other observations.

The percentage of the plot that must be taken as a sample (the sampling percentage) to obtain any given accuracy is related to the size of plot: the larger the plot, the lower the sampling percentage necessary. To obtain an error of 5% of the mean the sampling percentage for grain weight is approximately 5% in 1/20 acre plots, 15% in 1/100 acre plots and 43% in 1/600 acre plots if the plots are not subdivided. These percentages are similar to those calculated from various randomized block experiments in Cambridge.