1. With three different groups, each of two zebu and two zebu × Ayrshire grade oxen, and ten typical East African feeding stuffs, no significant difference was found between the average digestibility coefficients recorded with the zebu and the grade oxen.

2. The slight differences in feeding values were also of no practical significance.

3. Some of the zebu × Ayrshire cattle were 3/4 and others 7/8 Ayrshire but the higher grading to the European breed apparently did not affect the digestive powers.

In continuation of our work on the relative supplemental value of animal and vegetable protein concentrates (Woodman & Evans, 1951), a study has been made of the proteins in extracted soya-bean meal. It is probable that vegetable protein concentrates may vary among themselves in nutritive value and that the proteins of ground-nut meal, which were the subject of investigation in our previous experiments, could not for this reason be regarded as representative of vegetable proteins in general. The same basal diet, composed of roughly 2 parts of barley meal and 1 part of fine bran, together with a little lucerne meal and minerals, was again used in the present investigation.

An account is given of the results of two series of field experiments carried out at Rothamsted and Woburn in the years 1926 to 1936 on the effect of nitrogenous fertilizers on wheat. In the first series a comparison was made of the effects of early (March) and late (May) top-dressings, and in the second series a range of times of application from sowing to the end of May were tested.

At Rothamsted, the increases of yield of grain produced by the nitrogenous fertilizer were small and rarely significant, but they were greater at Woburn. On the average of all experiments, the effect of the fertilizer on yield of grain was independent of the time of application. In individual years, variation in effectiveness between times of application was found, and this was correlated with the amount of rain falling in a short period after the time of application. At Woburn, the effectiveness of the fertilizer decreased with increase in the amount of rain falling immediately after the application of the fertilizer, but at Rothamsted the effects were less clear and appeared to be in the opposite direction.

The effects on straw yield were relatively greater, and more consistent, than those on grain yield. A greater increase of straw yield was produced by early top-dressing (January–March) than by application at the time of sowing, and the increase declined steadily the later the time of topdressing. Shoot height was increased by the nitrogenous fertilizer, and varied with time of application in a similar manner to straw yield.

1. A study has been made of the formation of lateritic soils in Sierra Leone and the composition is given of some of the intermediate and final products formed.

2. The detrital soils in Sierra Leone appear on the whole to contain a higher proportion of alumina to silica than the residual soils.

3. The soils described are all reddish or yellowish red soils, light in texture and generally containing a high proportion of stones. They are acid in reaction and have a definite lime requirement. The mineral constituents are low, especially the potash and the exchangeable calcium. i. Soluble phosphorus is readily removed from a solution by these soils.

Yields of arable crops are commonly lower on the crop margins or headlands, but the nature of the relationship between yield and distance from the crop edge has not been clearly defined, nor have the reasons for lower marginal yields. Surveys of 40 winter wheat headlands were carried out in 2 years to determine how yield changed with distance, and what factors might influence this relationship. Two field experiments were also conducted over 3 years in winter cereal headlands, in which the effect of distance was measured under conservation headland and conventional (fully sprayed) management.

Yields in the headland surveys varied from 0·8 to 10·2 t/ha. An inverse polynomial regression model was fitted to yield and weed data. Best fits were obtained by using separate parameters for each site. Adjusting yields to take account of weed dry matter improved the non-linear fit between yield and distance from crop edge. Field experiments provided similar results but the non-linear relationship was not as apparent.

There was a negative relationship between soil compaction, as measured by a cone penetrometer, and yield in one field experiment, where soil density values were relatively constant. No relationship was found between pattern of nitrogen fertilizer application and yield. Conservation headland management resulted in lower yield at one experimental site, especially in the third year, but not at the other site. Where yields were affected, weed dry matter was higher in conservation headland plots than in fully sprayed plots.

Although greater weed competition appears to account for at least part of the observed yield reductions on headlands, the role of other factors, particularly soil compaction, needs further study. Increased weed infestation may be an indirect result of reduced crop competition caused by other adverse conditions.

A model which takes account of heterosis for total seed yield and autofertility was used to trace the evolution of the expected average inbreeding coefficient (F) of a synthetic variety of field beans under multiplication. In every case, the value of F rapidly approached an equilibrium value which depended largely on the amount of cross-fertilization and very little on the higher seed total set or amount of selfing on less inbred plants. There was no indication of any fluctuation in F from generation to generation when the proportion of cross-fertilization was constant. The possibility of reducing the coefficients of inbreeding of generations likely to be used on the farm (syn-4 and later) by hand pollination instead of open pollination of the parents and by promoting cross-pollination by artificial increases in numbers of bees or adjustment of environmental factors during multiplication were examined. Although the method of parental pollination had little effect, induced increases in bee activity led to significant reductions in F when the ambient frequency of bee pollinations was low. The generation at which this procedure gave the maximum effect was the final generation of seed increase (syn-3), but an alternative would be for farmers to use bees on the first commercial crop. In any case, only seed from crops with adequate bee pollination should be used to sow commercial crops.

As the breeding system was shown to be effectively very similar to one in which all plants are equally self-fertile, it should be possible to take account of the number (n) and coefficients of inbreeding (F0) and interrelationship (r0) of the parents, and to predict the yield of advanced generations using formulae given by Busbice (1969, 1970).

A regular optimum spacing among plants is the theoretical ideal. Regularity is difficult to secure and the ever varying optimum is not determinable. But earlier investigations have shown that field crops of corn are marked by extremely high fluctuation in population density along the rows of plants; and further, that in this fluctuation lies an important limitation to potential yield. Wider knowledge of this limitation is being sought. The experiments have clearly confirmed plant density fluctuation as a characteristic of field crops (of wheat). Measures of this fluctuation and analyses of its nature and causes are the subject of the paper.

In relation to plant development and yield, fluctuations in density or spacing from point to point along the row, are the most important features associated with drill action. These have been measured by counts, both of seeds and of plants, on unit lengths of row. Such “census” counts are described in detail for four normal fields. Plant counts were made periodically. In general a unit length of one foot of row was adopted. For analytical purposes the refinement of a per-inch count proved necessary.

Fluctuation in seeds deposited per foot may be illustrated by the data from one of the fields. The mean was 18·0 and the standard deviation was 7·2. In aggregate the field could be regarded as consisting of five equal portions (quintiles of the per-foot distribution) for which:

Number of seeds per foot = 5·0–12·2; 12·2–15·0; 15·0–18·0; 18·0–22·3.

Equivalent seeds rates (bushels per acre) = 1·42; 2·00; 2·35; 3·11; 3·70.

The distribution per inch, determined by a specially devised method, is illustrated for two fields in Diagram I. Four equal aggregates (quintiles of per-foot distribution) from one and the same acre had the widely different seedings displayed in Diagrams II and III.

1. Rumen and caecal wall tissues were taken at slaughter from lambs varying in age from newborn to 11 weeks. The ability of these tissues to metabolize the short-chain fatty acids, acetic, propionic and butyric acid was compared with tissues from adult sheep. Ketone body production was measured.

2. The utilization of butyrate by the rumen wall in the newborn lamb was lower than in the adult, but exceeded the adult levels at 3 weeks of age and maintained this higher utilization to 11 weeks and probably longer. Ketone body production was negligible at birth but followed butyrate utilization closely thereafter.

3. The caecal wall in the newborn lamb utilized butyrate at a much higher rate than the adult sheep tissue. Foetal lamb caecal tissue utilized butyrate to the same extent as in the newborn lamb. Levels were, however, typical of the adult within a day or two of birth and showed no subsequent effect of age. Ketone body production was negligible at all ages.

4. Rumen development in milk-fed lambs slaughtered at 7 and 9 weeks of age was retarded anatomically and showed decreased capacity in the utilization of butyrate.

5. The utilization of acetate and propionate by rumen and caecal tissues showed no marked change due to age. Ketone body production from these acids was low.

The dates of transplanting and maturity of twenty-four experiments between 1980 and 1986 with the lettuce varieties Saladin and Saladin R 100 were used, together with meteorological data for each crop, to study the planning of crop continuity and the prediction of crop maturity. The interval in days from transplanting to maturity was shown to be a minimum for crops transplanted around the middle of June and was described by a fitted quadratic relationship which accounted for 34·6% of the variance. When expressed in accumulated day-degrees >0 °C the interval increased with later transplanting but a linear relationship accounted for only 22·2% of the variance. However, when expressed as accumulated solar radiation the interval decreased with later transplanting and a linear relationship accounted for 82·2% of the variance. When expressed in effective day-degrees (EDDs) the interval was relatively stable at 589 EDDs (S.D. = 39·5).

Predictions of commercial crop maturity based on these relationships and using a combination of average and observed meteorological data showed that EDDs gave the most accurate prediction. Differences between actual and predicted maturity appeared to be associated with the site of production, suggesting that a ‘site’ factor needs to be incorporated to take account of local differences in temperature, solar radiation and soil type. The use of long-term average day-degree and EDD data was less consistent than estimates of maturity based wholly or predominantly on observed day-degree and EDD data though with solar radiation the reverse was true.

1. In the previous paper of this series (Callow, 1949) a special method of graphical analysis was developed in order to calculate the effect of different rates of fattening on the percentages of fatty tissue, muscular tissue and bone, etc., in a carcass. This method has been used in the present paper to calculate the effect of different rates of fattening on the deposition of chemical fat and protein in the fatty and muscular tissues of a carcass during fattening.

2. The method of analysis depends (a) on the choice of an arch-type carcass on mathematical and biological grounds, and (b) the use of partition percentages for defining the proportions of fat, protein and water laid down in the fatty and muscular tissues during an increase in carcass weight due to fattening.

Organically grown lucerne (Medicago sativa L.) should ensure sufficiently high forage and seed yields to sustain the profitability of organic production chains. Twenty lucerne populations were evaluated for forage dry matter (DM) yield over 3 years (2005–7), and for seed yield and its components in the third year, under organic management and a mowing regime in Lodi (sub-continental climate with sandy-loam soil) and Perugia (sub-Mediterranean climate with silty-clay soil). The objectives were to assess the impact on lucerne forage and seed yield of: (i) type of germplasm (landrace or commercial cultivar); (ii) plant growth habit (erect or non-conventional); (iii) area of germplasm origin or selection (northern Italy north of the Po river, NI-N; northern Italy south of the Po river, NI-S; central Italy, CI). The populations included seven cultivars selected under conventional management and one selected under organic management, seven landraces and five breeding selections, of which one was semi-erect and one was semi-prostrate. On average, cultivar and landrace germplasm types did not differ for forage or seed yield in any geographic set of populations (NI-N, NI-S or CI), except for the higher seed yield of landraces in one set. Compared with erect germplasm, semi-prostrate germplasm exhibited distinctly lower forage and seed yield, especially where weed competition was severe (Lodi) because of poor competitive ability. Semi-erect germplasm tended to have lower forage yield across locations. Specific adaptation was the main determinant of forage and seed yield responses of landraces and cultivars. Erect populations originated in NI-N were high yielding in the test site similar to NI-N environments (Lodi) and low yielding in the location representing CI environments (Perugia). Populations that originated in CI, including the cultivar selected under organic management, displayed the opposite adaptive response. Populations that originated in NI-S, whose major environmental characteristics were somewhat intermediate between NI-N and CI, tended to be mid-ranking for forage and seed yield in each site. The large cross-over population×location interaction was confirmed by the lack of genetic correlation for forage yield (rg=−0·25, P>0·20) and the negative genetic correlation for seed yield (rg=−0·68, P<0·05) of populations across locations. No genetic correlation across locations was found for density of fertile tillers and pod fertility. The association of population seed yield with its component traits was site-specific. Cropping and seed multiplication of locally adapted erect cultivars have paramount importance for mown organically grown lucerne in Italy.

The heat production of hens and cockerels of a White Leghorn strain (‘H & N’) was measured after acclimation to environmental temperatures of 16, 23, 27 and 33 °C. No difference in fasting heat production was found between 16 and 23 °C for well-feathered hens in the first few months after moult though there were substantial reductions at 27 °C and above. Both hens and cockerels showed a trend of increasing net availability of metabolizable energy with increasing environmental temperature though this was non-significant. There were significant reductions between 16 and 27 °C in the metabolizable energy requirements for maintenance for both sexes.

Results are also given for the heat production of laying hens exposed to short daylight periods and high or low environmental temperatures. Although the mean fasting heat production of the high-temperature group was greater, the difference was not statistically significant.

Two seed-resistant land races were crossed to a seed-susceptible cultivar to produce Fl, F2, BC1; and BC2 generations. It was observed that seed resistance was conditioned by two unlinked recessive genes and cytoplasmic factors. Similarly, generations derived from a pod-resistant, seed-susceptible cultivar with a seed-resistant, pod-susceptible land race demonstrated that seed and pod resistance are independently inherited.

Male sterility in potatoes, that is the absence of pollen from the anthers, has been shown by one of us (Salaman(1)) to behave as a recessive to male fertility. The present paper is an account of some farther experiments in the genetics of this character, particularly of crosses between two varieties in which the reciprocals give different results.

Both quantity and quality of pollen were estimated by methods similar to those used by Salaman(1) Four empirical grades of quantity were employed, viz. “abundant,” “midium,” “small” and “very few grains.” The quality of the pollen was determined by mounting a sample in water and examining microscopically. Under this treatment living and presumably healthy grains swell up, appear spherical and translucent, whilst the pores become prominent. Such grains are termed “good.” Bad grains are generally smaller, irregular in outline, and often appear quite empty.

This study was initiated to evaluate the short-term (< 3 years) ability of some selected acid-soil adapted hedgerow species when planted in alley cropping systems to improve soil properties in a newly-cleared Ultisol (Typic Kandiudult) of southern Cameroon, 1990–92. The hedgerow species selected were Senna (Senna spectabilis), Flemingia (Flemingia congesta)and Acioa (Acioa barterii). A non-alley-cropped control was also included in the trial. The greatest quantities of prunings, and hence, mulch were produced by Senna and Flemingia. Exchangeable Ca, effective CEC and water infiltration were greatly increased in the alleys of plots where either Flemingia or Senna had been planted within 2·5 years of hedgerow establishment. The large amounts of mulch produced by Senna and Flemingia did, however, result in soil temperatures greater than those of the control or Acioa plots c. 1 year after application of the prunings as mulch. Root growth of Senna in the subsoil was significantly greater than that of either Acioa of Flemingia, but that of cassava was reduced by alley cropping with all three hedgerow species. Compared to the control or alley cropping with Acioa, maize and cassava yields were greater when alley cropped with either Flemingia or Senna hedgerows.

Leaves of olive trees (Olea europaea L.) of eight cultivars, Manzanilla, Picual, Hojiblanca, Edremit, Conservolia, Picholine-Marroqui, Chemlali and Frantoio, were collected in different seasons and years in Córdoba, Spain. Their chemical composition and in vitro organic matter digestibility values were determined. Differences in composition and nutritive value between cultivars, years and seasons were studied in Manzanilla, Picual and Hojiblanca, the three most important local cultivars. There were significant differences both between cultivars and seasons (P < 0·05) and a non-significant difference between years.

The effect of various drying procedures (fresh, oven-dried, air-dried indoors or air-dried outdoors) on chemical composition, in vitro digestibility and in vivo digestibility in sheep was also examined. The in vivo organic matter digestibility of fresh leaves was significantly higher than that of dried leaves. No difference was found between leaves air-dried indoors and oven-dried leaves. However, leaves air-dried outdoors were significantly less digestible. Quick drying in an oven reduced the digestibility of crude protein and acid detergent fibres compared to air drying indoors. There was a significant decrease in digestibility of 11% when leaves were dried separated from the branches as compared to leaves dried on the branches.

Evidence is provided to prove that the nutritional malady, Coast Disease, which affects sheep de-pastured without change on the shell-sand littoral of South Australia is due solely to the inability of the pastures to provide the quantity of cobalt and copper necessary to fulfil the nutritional requirements of grazing sheep.

An experiment started in 1936 in which five evenly matched groups of young cross-bred ewe hoggets were dosed thrice weekly with cobalt, copper, cobalt plus copper, and with cobalt plus copper together with iron, manganese, zinc and nickel is described.

Crop-based protein self-sufficiency in Finland is low. Cereals dominate the field cropping systems in areas that are also favourable for legumes and rapeseed. The present paper estimated the realistic potential for expanding protein crop production taking account of climatic conditions and constraints, crop rotation requirements, field sizes, soil types and likelihood for compacted soils in different regions. The potential for current expansion was estimated by considering climate change scenarios for 2025 and 2055. By using actual regional mean yields for the 2000s, without expecting any yield increase during the expansion period (due to higher risks of pests and diseases), potential production volumes were estimated. Since rapeseed, unlike grain legumes, is a not a true minor crop, its expansion potential is currently limited. Thus, most potential is from the introduction of legumes into cropping systems. The current 100000 ha of protein crops could be doubled, and areas under cultivation could reach 350000 and 390000 ha as a result of climate warming by 2025 and 2055, respectively. Such increases result mainly from the longer growing seasons projected for the northern cropping regions of Finland. Self-sufficiency in rapeseed could soon increase from 0·25 to 0·32, and then to 0·50 and 0·60 by 2025 and 2055, respectively. If legume production expands according to its potential, it could replace 0·50–0·60 of currently imported soybean meal, and by 2025 it could replace it completely. Replacement of soybean meal is suitable for ruminants, but it presents some problems for pig production, and is particularly challenging for poultry.

Effectiveness of the polyethylene glycol (PEG) test for measuring cell membrane stability (CMS) to select drought-tolerant genotypes in wheat was investigated. PEG test was compared with two other tests. Genetic variability of CMS was also investigated.

Drought was induced artificially in pot-grown plants and in excised leaves, and percentage injury in leaf tissues by drought stress as measured by CMS was compared with that by PEG test. Percentage injury in leaf tissues of pot-grown plants was not correlated significantly with that by PEG test. However, percentage injury in excised leaves was well correlated with that in PEG test. The results suggest that the PEG test has merit in measuring drought tolerance in wheat. Frequency distribution of CMS in winter wheat lines was closely related to the characteristic pattern of quantitative inheritance and therefore CMS of wheat seems to be controlled by polygene action.

Four field experiments over 2 years investigated whether wheat hybrids had higher nitrogen-use efficiency (NUE) than their parents over a range of seed rates and different N regimes. There was little heterosis for total N in the above-ground biomass (NYt), but there was high-parent heterosis for grain N yields (NYg) in two of the hybrids, Hyno Esta and Hyno Rista, associated with greater nitrogen harvest index (NHI). Overall, the hybrids did not significantly increase the total dry matter produced per unit N in the above-ground crop (NUtEt), but did increase the grain dry matter per unit N in the above ground crop (NUtEg). The improvement in NUtEg was at the partial detriment of grain N concentration. Heterosis for grain NYg in Hyno Esta was lower at zero-N, suggesting that it did not achieve higher yields through more efficient capture or utilization of N. The greater NHI in Hyno Esta appeared to be facilitated by both greater N uptake, and remobilization of N from vegetative tissues, after anthesis.

The response of N efficiency and uptake to seed rate was dependent on N supply and season. Where N fertilizer was applied, N uptake over time was slower at the lower seed rates, but where N was withheld N capture at the lowest seed rate soon approached the N capture of the higher seed rates. During grain filling, the rate of accumulation of N into the grain increased with seed rate and the duration of N accumulation decreased with seed rate. With N applied, N yields increased to an asymptote with seed rate, when N was withheld there was little response of N yields to seed rate. In 2002, N utilization efficiency (NUtEt and NUtEg) also increased asymptotically with seed rate, but in 2003 seed rate had little effect on N utilization efficiency. When nitrogen fertilizer had not been applied, NHI consistently decreased with increasing seed rate. The timing of N application made little difference to NUE, NY, or NUtE.