1. Seven experiments on spring barley and five on spring wheat carried out in 1955–7 compared dressings of ammonium sulphate and calcium nitrate applied to the seedbeds at 0·3 and 0·6 cwt. N/acre. The fertilizers were tested both when broadcast and when drilled with the seed.

2. Consistently higher yields of barley were produced by drilling than by broadcasting ammonium sulphate. Drilling calcium nitrate at 0·3 cwt. N/acre was superior to broadcasting for barley but when applied with the seed at 0·6 cwt. N/acre this fertilizer retarded germination and early growth and gave smaller yields than were obtained by broadcasting. Broadcast dressings of both fertilizers gave higher yields of wheat than combine-drilled dressings. There is a considerable risk of fertilizer ‘scorch’ when compound fertilizers containing all their nitrogen in nitrate form are combine-drilled at rates sufficient for maximum yield. This risk may be discounted when adequate rain follows drilling but the check to germination may be sufficient to reduce yields in dry springs, on light soils, and on badly prepared seedbeds. Fertilizers containing all their nitrogen in ammonium form appear to be quite safe at the rates of dressing tested in this work.

3. Calcium nitrate and ammonium sulphate gave similar yields and nitrogen contents of both crops when the fertilizers were broadcast on the seedbed. Nitrates applied at sowing-time to cereals grown in the drier parts of the country do not appear to be leached out of the root-zone before they can be taken up by crops.

The technique of radiography has been used successfully to provide permanent records of mature and developing pods in oil-seed rape. X-ray films and photographs of the pods show clearly the shape and size of the pods as well as the numbers, positions and to some extent the size of the seeds within them.

1. An experiment designed to investigate the growth and yield of lucerne over a wide range of plant populations is described and the results discussed.

2. The mean yields of lucerne per plant were fitted to three different equations relating yield per plant to plant population, and the ‘goodness-of-fit’ of these equations was compared.

3. As plant population increased, the yield of lucerne per acre increased very rapidly up to a certain level, but further increases in plant population led to much smaller increments in yield. It is argued from theoretical considerations that the yield per acre would reach a maximum only when the plant population is infinite.

A Considerable area of pasture land in Mid-Somerset, known locally as “teart” land, and also a smaller area in Warwickshire, cause scouring in cattle at certain times of the year. These pastures are a source of loss to the farmers and, from time to time, have been the subject of investigation. In 1862 the late Dr J. A. Voelcker published a valuable report on the subject, and in the main the observations and results discussed in the present paper are consistent with the suggestions which he put forward. Details of more recent work are to be found in various reports in the Journal of the Bath and West Society from 1895 to 1904.

The biology of some host-adapted populations of A. gossypii and the comigration band mobilities of aphid enzyme extracts were studied in 1992 in Kochi, Japan. Results indicated that biologically there are no significant differences between eggplant, cucumber and watermelon aphid populations with regards to longevity and the number of offspring produced per female aphid. However, in all populations, adult survival declined significantly within 5 days of introduction onto a new host from the original. No genetic differences were observed between populations since they scored equally at seven different enzyme loci: malic enzyme (ME), glucosephosphate isomerase (GPI), isocitrate dehydrogenase (1DH), phosphoglucomutase (PGM), 6-phosphogluconate dehydrogenase (6-PGD), malate dehydrogenase (MDH) and naphthylacetate linked esterase (EST). Also, protein bands, as revealed by SDS-PAGE, as well as carboxylesterase banding patterns, showed no differences between populations. These results indicate that the various host-adapted populations of A. gossypii infesting a wide range of solanaceous and curcubitaceous crops can be treated as single species devoid of genetic variability. The slight differences in biology and behaviour found between the various hostadapted populations can be attributed to physiological variations, differences in host nutrient composition, and possibly to some unknown co-existing biotic factors.

Seven experiments on winter barley, made during 1979–81, measured the effects of several amounts of nitrogen, applied at different times in spring, on grain yield and nitrogen content. All of these experiments also tested a growth regulator applied in spring, and five of them tested fungicide sprays. In 1980 the experiment at Rothamsted also tested sowing dates, and an eighth experiment, also at Rothamsted in 1980, tested sowing dates and mildew fungicides applied in autumn or spring. In all the experiments treatments were tested in factorial combination.

N applied in February was less effective than N applied in March and both were less effective, in terms of grain yield, than N applied in April. Divided dressings were best applied in February and April or March and April; effects on % N in grain followed the same pattern and so, therefore, did the efficiency of uptake of fertilizer N. The growth regulator consistently reduced the length of the straw and diminished lodging; it increased yields in five of the seven experiments in which it was tested.

Responses to fungicides were inconsistent from year to year. Sowing in September rather than in October 1979 increased yield in both of the experiments at Rothamsted in 1980, especially of the 6-row variety Hoppel.

Two experiments were conducted with four lactating cows in a latin-square design. The rations were composed mainly of maize silage plus concentrates, supplemented with urea, Pruteen, or soya-bean meal supplying 25% of total dietary N. Nitrogen and energy balances were measured, and milk production recorded.

Dry-matter digestibility, intake of metabolizable energy (ME) and ME concentration in dietary dry matter were not significantly altered when Pruteen was substituted for soya-bean meal. However, mean nitrogen digestibility for all the treatments was significantly lower than expected from published relationships.

The substitution of Pruteen for soya-bean meal did not significantly affect the nitrogen balance of the animals or milk production, but the latter tended to be higher than that recorded with urea.

The responses to the different N supplements are discussed in relation to the feeding systems of the Agricultural Research Council and the French Protéines Digestibles dans l'lntestin Grêle, and are compared with predictions made from statistical relationships developed in our laboratory.

Canola (Brassica napus L.) meal is widely used in animal feed as a protein source, and its quality relies on protein and amino acid content. However, little information is available regarding amino acid regulation in canola seed with nitrogen (N) application. The present study is aimed to evaluate the effect of N rate and genotype on canola seed amino acid concentrations under field conditions. A split-plot design comprising four N rates (0, 120, 240 and 360 kg N/ha) and three genotypes differing in seed protein content were used in 2010/11 and 2011/12. The results showed that increasing N rate decreased seed oil content linearly but increased seed protein content in all of the genotypes. The total amino acid concentration and absolute concentrations of individual amino acids in canola seed also improved significantly with the N rates in all of the genotypes. Regarding the proportions of amino acids, a group that included glutamic acid (Glu), proline (Pro) and arginine (Arg) dominated and occupied > 0·30 compared with other amino acids. The ratio of amino acids in this group increased by 8·3% with 360 kg N/ha compared with the control. However, the proportions of the other amino acids showed negative responses to the N rates. The results of regression analysis of the responses of individual amino acids to N rate indicated that Glu, Pro and Arg had a greater improvement potential with application of N fertilizer, as revealed by higher slopes in the linear equations compared with the other amino acids. Additionally, the concentrations of sulphur-containing amino acids, methionine and cysteine, were also a potential target for improving with N application because these are always deficient in major crops. In conclusion, N application cannot only improve seed protein content but also enhance deposition of amino acids such as Glu, Pro and Arg.

Adult sheep, unweaned and mature weaned calves have been examined by metabolic studies for sodium balance. The ratio of sodium input/output was near unity with only a very small amount of the ingested sodium salt being retained. A positive sodium balance was always present, with excess sodium salt being excreted. The main channel of sodium excretion was the kidney, although when sodium intake was increased the sodium content of the faeces showed a proportional increase. Unweaned calves, a few days old, were quite able to excrete excess sodium salts in concentrated urine.

There was a clear difference in preference for sodium salts over water, between weaned calves allowed access to sodium salts while being fed milk, and weaned calves denied sodium salts at the milk feeding stage. Sodium-naive calves showed a marked preference for sodium salt solutions while the sodium-experienced calves showed at best an indifference and sometimes even an aversion. With continued access to sodium salts the volume ingested declined steadily in both groups but food intake remained constant.

In both calves and sheep the preference for sodium salts showed considerable variation between animals. The evidence from parallel metabolic studies suggests that this variation indicates that salt intake is controlled by some mechanism, possibly in the central nervous system, which is activated by dynamic sodium metabolism. Our experimental results confirm that ruminants have a well developed salt taste but predilection for sodium salts could be a biochemical manifestation rather than a hedonic propensity.

Results of visual and radiographic development of the mandibular caudal teeth were obtained from 135 cattle between 1 and 2 years old. Age ranges for each stage of tooth development were obtained. Using visual assessment of second molar intra-oral eruption the maximum age range before animals could be differentiated was 8 months (1 year 3 months from 1 year 11 months). Animals showed different stages of development in all six teeth using criteria based on resorption of the temporary premolar teeth and crown and root formation in the permanent premolar and molar teeth. The maximum age range before animals could be distinguished was 5 months (1 year 6 months from 1 year 11 months) and at all other ages the age difference before differentiation was less.

1. The discrepancy between the results obtained by various workers concerning the inheritance of earliness or the time of ear emergence in cereals, suggests that this character needs further elucidation physiologically before genetic analysis can be properly undertaken.

2. A study of the ear emergence characteristics of varieties when grown under varying conditions indicates that the expression of this character is very much affected by the growing conditions, and the physiological basis must be understood before the various expressions of earliness and lateness are appreciated. It is therefore suggested that the genetic analysis should be conducted in conjunction with a physiological analysis and with a proper consideration and understanding of the effect of environment.

3. A series of crosses involving parental forms differing in time of ear emergence, and in some cases belonging to different physiological groups, has shown how differences in genetic behaviour can to some extent be correlated with the physiology of ear emergence of the parents.

4. In one cross involving similar types, no evidence of segregation or large genetic difference was obtained. In two crosses involving larger differences of similar types, evidence for a single major factor difference was obtained. In other crosses between different physiological types, and an unstable form, more complex genetic results including transgressive inheritance were obtained. Still other crosses superficially suggested a 3: 1 ratio in the F2, but the presence of a certain amount of transgression, and the behaviour of the F3, pointed to a more complicated relationship.

5. Two crosses involving different physiological types were studied in the F1 and the F2 when sown at different times in the spring by dividing the progenies into separate portions. It was shown that the behaviour of the F1 and the F2 of the same cross was materially affected by the sowing time.

By means of a suitable fluid and a low temperature, it has been possible to keep mammalian spermatozoa in a condition of potential motility for 9 days.

Two systemic fungicides, benomyl and thiabendazole, were more active than the non-systemic fungicide Drazoxolon in inhibiting fungal growth in vitro. A similar pattern was obtained in glasshouse trials with benomyl and thiabendazole giving adequate protection at low concentrations while Drazoxolon was ineffective unless applied at 50% the commercial product concentration. A field trial using thiabendazole, Drazoxolon and a mixture of benomyl and thiram confirmed the glasshouse results.

Some phytotoxicity was noticed with high concentrations of both benomyl and thiabendazole, but satisfactory disease control was achieved using fungicide concentrations which did not induce phytotoxicity.

An analysis is suggested for an experiment investigating plant competition between different genotypes grown in pure culture and in binary mixtures with unequal proportions of genotypes. Worked examples are presented.

Three experiments conducted over two years (2002–04) at the Crops Research Unit, University of Reading, investigated competition between autumn sown oilseed rape cultivars (Brassica napus L. ssp. oleifera var. biennis (DC.) Metzg.) and Lolium multiflorum Lam., L.×boucheanum Kunth and Alopecurus myosuroides Huds., sown as indicative grass weeds.

Rape cultivar (cv.) had a substantial effect on grass weed seed return. Over the six cultivars tested, L. multiflorum spikelet production ranged from just under 400 spikelets/m2 in the presence of cv. Winner to nearly 5800 in competition with cv. Lutin. Cultivar competitiveness was associated with high biomass, large dense floral layers and early stem extension. There was some evidence of differential competitive tolerance between rape cultivars.

The results suggested that rape cultivars could be screened for competitiveness by measuring floral layer interception of photosynthetic active radiation.

L.×boucheanum cultivars varied in ability to compete with rape. In the absence of inter-specific competition, spikelet density was similar for Aberecho and Polly (circa 31 000 spikelets/m2) but when grown with rape Polly outyielded Aberecho (i.e. 12 090 and 7990 spikelets/m2 respectively).

The genetic effects, including genetic main effects and genotype×environment (G×E) interaction effects, for oleic acid content (OAC) and linoleic acid content (LAC) at five different developmental times/stages were studied using unconditional and conditional genetic models for seed quantitative traits in diploid plants. The unconditional analysis results revealed that both OAC and LAC were simultaneously controlled by diploid embryo nuclear genes, cytoplasmic genes and diploid maternal plant nuclear genes and their G×E interaction effects. Effects on the embryo and cytoplasm were found to be more important for OAC at different developmental times while maternal effects, in combination with cytoplasmic effects, were more important for LAC at most development times. The conditional analysis revealed that the net effect from expression of maternal genes was more important for both traits at most developmental stages. The total narrow-sense heritability was high for both OAC and LAC, with general heritabilities being more visible for OAC and G×E interaction heritability being more important for LAC at most development times. The predicted genetic effects indicated that while most parents (with the exception of Youcai 601, Zhongyou 821 and Eyouchangjia) could be used for improving OAC of offspring, Double 20-4 was the most appropriate for improving LAC due to its better stability and positive values across environments at most development times.

An isotope dilution method using [U-13C]glucose and a glucose clamp approach were applied to determine the effects of supplemental chromium (Cr) and heat exposure on blood glucose metabolism and tissue responsiveness and sensitivity to insulin in sheep. The sheep consumed diets with either 0 or 1 mg of Cr/kg (Control and +Cr diet, respectively) from high-Cr-yeast, and were exposed from a thermoneutral environment (20 °C) to a hot environment (30 °C) for 5 days. Blood glucose turnover rate did not differ between the diets, and was lower (P < 0·05) during heat exposure than in the thermoneutral environment. The maximal glucose infusion rate (tissue responsiveness to insulin) tended to be lower (P = 0·06) for the +Cr diet than for the Control diet, but did not change with heat exposure. The plasma insulin concentration at half maximal glucose infusion rate (tissue sensitivity to insulin) did not differ between the diets, and was greater (P < 0·05) during heat exposure than in the thermoneutral environment. No significant diet × environment interactions were observed. There was no significant evidence that Cr supplementation moderated heat stress in sheep from the measures of blood glucose metabolism and insulin action.

Proximal colons taken from foetal and newly born lambs have been shown to actively transport methionine from lumen to blood when incubated under in vitroconditions. The lumen to blood flux of methionine, measured across foetal and early post-natal colons was approximately 25 and 15 times greater than the blood to lumen flux, each flux being determined in the presence of 1 mM methionine.

The ability of the colon to transport methionine decreased with age, there being no net transport across the colon of a 26-day-old lamb. The post-natal disappearance of this transport function appeared to be roughly exponential with a half-time of approximately 2 days.

The short-circuit currents and open-circuit voltages, measured across proximal colons of lambs of different ages, remained stable throughout incubation. The transtissue electrical resistance of colons taken from 9- and 16-day-old lambs was approximately double that recorded across colons taken from younger animals.

These results are discussed both in relation to what is already known concerning amino acid transport in the neonatal pig colon and in relation to what their possible physiological significance might be to normal post-natal development in lambs.

1. The changes which have occurred in the nutrition of young dairy stock are discussed. It is emphasized that any food shortage of a farm affects young cattle before the rations of the cows are reduced.

2. An estimate of minimum protein level is developed using Mitchell's (1926) method.

3. An experiment designed to show the optimal level of protein in the ration for growing stock showed a difference between this minimum estimate and the optimal. Some considerable economy in protein can, however, be effected in Wood & Woodman's (1936) standard is the one normally used to calculate rations.

4. The growth of young cattle on protein supplemented wartime dietaries of straw is shown to be below that of heifers fed the rations more normal in peace time.

5. Stunted cattle undergrown by 7–8 months when 18 months to 2 years old have been found. This has been attributed to the effects of wartime rations.

Summer pumpkin (Cucurbita pepo L.) is an herbaceous plant with big fruits and oily seeds. Photosynthetic oxygen release was previously proposed to promote storage activity of seeds under internal hypoxia, in particular in oilseeds. Photosynthetic activity or any other function of chlorophylls from pumpkin seeds has never been demonstrated. The aim of the present research was to test whether illumination of pumpkin fruits has any influence on the yield and to measure photosynthetic activity of pumpkin seeds. The fruits grown in the dark were not significantly different from controls exposed to light in regard to fruit weight, size, number and weight of seeds or the content of lipids and pigments. Delayed fluorescence measurement showed no photosynthetic activity in pumpkin seeds in any developmental stage. Fruit wall, on the other hand, had significant photosynthetic activity. It is concluded that chlorophyll in pumpkin seeds does not mediate photosynthesis, which would in turn result in increased pumpkin yield.