bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiological studies of competition in Zea mays L: II. Effect of competition among maize plants
Authors: Eddowes Maurice
Published: March 2009

There was no measurable competition among plants before the four-leaf stage of growth. Competition among plants after the four-leaf stage reduced their average weight and their capacity to store assimilates in the ear after anthesis. As competition intensified total dry-matter yield at lower plant populations approached progressively the yield at the highest plant population. Total whole plant yield per unit area showed an asymptotic response to increase in plant population. Ear yield per unit area showed a parabolic response.

On a unit leaf area basis, the top three leaf laminae apparently contributed about 66% more to cob (rachis + grain) dry weight than the three adjacent leaf laminae immediately below them.

Ear weight per plant was reduced, either (a) by increasing plant population, or (b) by partial defoliation, or (c) by both treatments. In situation (c), i.e. where high plant populations were partially defoliated, cob weight per plant was apparently determined by the amount of available assimilates, and not by ear storage capacity.
Physiological studies of competition in Zea mays L: III. Competition in maize and its practical implications for forage maize production
Authors: Eddowes Maurice
Published: March 2009

Competition among maize plants in the vegetative stage of growth was postponed by application of nitrogen to the seed bed and by maintaining soil moisture near field capacity. The amount of available nitrogen was a critical factor in determining the effect of the competitive balance between nitrogen and light on maize yield. The supply of either affected the capacity of the crop to utilize the other, but ultimately light became the dominant factor.

Soil moisture deficits of up to 1.0 in from field capacity, in the early stages of vegetative growth, did not reduce dry-matter accumulation and uptake of nitrogen, but in the absence of weed competition and post-planting cultivation soil moisture losses in the early stages of crop growth may be small.

In 1966, maize responded quicker to surface applied than to deep-placed nitrogen and utilized the surface applied nitrogen for dry-matter accumulation more effectively.

Provided that there was initially an adequate supply of nitrogen in the seed bed, there appeared to be no advantage to total yield from application of nitrogen top dressings to maize. In the West Midlands, under conditions of adequate nutrient and soil moisture supply, the optimum plant population for commercial production of forage maize was about 40000 per acre.
A new method of arranging variety trials involving a large number of varieties
Authors: Yates F.
Published: March 2009

A new method of arranging variety trials involving large numbers of varieties is described. This type of arrangement, for which the name pseudo-factorial arrangement is proposed, enables the block size to be kept small without the use of controls.

Various possible types of pseudo-factorial arrangement are discussed in detail and the necessary formulae developed. The appropriate methods of computation are illustrated by numerical examples based on the results of a uniformity trial on orange trees. It is shown that pseudofactorial arrangements are likely to be more efficient than arrangements involving the use of controls. In cases where there is considerable soil heterogeneity they are also markedly more efficient than randomized blocks containing all the varieties. In the chosen example gains in efficiency ranging from 26 to 57 per cent, were obtained.
A note on the analysis of covariance
Authors: Bartlett M. S.
Published: March 2009

1. In recent papers which refer to the use of covariance there has still appeared an occasional lack of understanding of this method of statistical analysis. There have, for example, been references in the literature to methods of analysis which the writer has used in certain problems as if they were in competition with the use of covariance as described by Fisher (1, 2). It would therefore seem to be of value to indicate briefly the different situations in which covariance may prove of use, in order that the distinction between some of these situations may be clearly realised.
Serum phosphatase in the domestic fowl
Authors: Common R. H.
Published: March 2009

1. Some observations on the serum phosphatase of the domestic fowl are described. Laying hens, held to be normal birds, had higher and more variable serum phosphatase than cocks. No great difference in serum phosphatase could be found between laying hens and hens in a period of suspended egg production. Pullets from another source and which had never laid gave values comparable with the value for cocks.

2. The serum phosphatase of chicks shows a rapid increase to a maximum at about 10–12 days after hatching, followed by an equally sharp fall to a lower level at 3 weeks. Thereafter, the values for male birds fall regularly until maturity. The values for female birds correspond closely with the values for male birds until the onset of laying, when they increase again, but to a varying degree in different individuals.

3. An attempt to reduce the range of variation of serum phosphatase in laying birds by administration of 1 ml. per bird per diem radiostol B.D.H. (3000 international units vitamin D per ml.) was not successful.

4. Serum phosphatase showed a much greater increase during laying in pullets receiving a low calcium ration (0·37 per cent. CaO) than in pullets receiving the same ration supplemented with calcium carbonate (3·10 per cent. CaO).

5. Serum phosphatase is greatly increased in chicks suffering from rickets.
Effect of continuous removal of open flowers on the seed yield of two varieties of cowpea, Vigna unguiculata (L.) Walp.
Authors: Ojehomon O. Ojeaga
Published: March 2009

When open flowers were removed from cowpea plants for periods between 3 and 12 consecutive days beginning from the first day of anthesis, more flowers opened on the deflowered than on the untreated plants, thus compensating for those removed. However, most of these extra flowers dropped prematurely.

In experiments in the greenhouse or on dry-season irrigated plots, deflowering for up to 9 days did not decrease the seed yield of the varieties Adzuki or Westbred. In an early-season field experiment, deflowering of Westbred did not decrease the seed yield unless repeated for 12 days. All periods of deflowering Adzuki decreased the seed yield, and the longest period gave the smallest yield.
Potassium: calcium exchange in soils of the Broadbalk experiment at Rothamsted
Authors: Addiscott T. M.
Published: March 2009

Soils from Broadbalk field were used to find whether differences in K-manuring had altered K:Ca exchange relationships during 100 years cropping with wheat, by measuring cation exchange capacities and quantity/intensity (Q/I) relationships.

Cation exchange capacities (CECs) were measured with and without the contribution of the soil organic matter and the following mainly non-significant trends arose during 100 years: (1) The CECs of plots given K fertilizer increased slightly when the organic contribution is included and decreased slightly when it is not. (2) The CEC of the plot given farmyard manure increased greatly when the organic contribution is included and decreased slightly when it is not. (3) The CEC of the unfertilized plot increased very slightly, whether or not the organic contribution is included.

The K buffer capacity, the slope of the Q/Icurve when the soil neither gains nor loses K, was related to the K saturation of the CEC better when the organic contribution was omitted from the CEC than when it was included, suggesting that K: Ca exchange measured by the Q/Icurves occurs mainly on the non-organic part of the CEC. Two soils depleted of K had anomalously large buffer capacities, but two undepleted samples behaved similarly.

Superimposing Q/Icurves by eye showed no appreciable differences between samples from different years or from different plots, even at large activity ratios. Plotting exchangeable K against I0, the activity ratio when the soil neither gains nor loses K, gave a single curve embracing all plots from all years, similar to the superimposed Q/I curves. Long–term manuring with ammonium sulphate has not affected K–Ca exchange.
Apparent digestibility, nitrogen utilization, water metabolism and heat tolerance of Brahman cross, Africander cross and Shorthorn x Hereford steers
Authors: Vercoe J. E. , Frisch J. E. , Moran J. B.
Published: March 2009

A study was made of the effect of increased rectal temperature on digestibility, nitrogen balance and water metabolism in Brahman x British (BX), Africander x British (AX) and Shorthorn x Hereford (SH) steers fed a fixed amount of lucerne hay.

An increase in rectal temperature of c. 1·4 °C caused a decrease in food intake and nitrogen balance and was associated with an increase in dry-matter digestibility in all breeds. Both dry-matter and nitrogen digestibilities were consistently higher in the Zebu crossbreds (BX and AX). Water intakes and ‘water balance’ (water intake – faecal and urinary water) were higher in all breeds when rectal temperatures were elevated. Water intakes were highest in the BX at both normal and elevated temperatures and increased most in the AX with an increase in temperature. ‘Water balances’ were similar in all breeds at normal body temperatures (4–5 1/day) but were lowest in the SH at elevated temperatures. This could partly explain the lower heat tolerance of the SH steers observed under these experimental conditions.
High Level Cereal Diets for the Growing/Finishing Pig: VII. The Performance Of Weaned Pigs Grown To Cutter Weight (160 lb live weight) on Iso-Nitrogenous-Maize Based Diets Containing Different Levels of Lysine and Tryptophan
Authors: Lawrence T. L. J.
Published: March 2009

In a randomized block 3x2 factorial experiment 72 Large White type weaner pigs were individually and restrictedly fed, from 501b (22–7 kg) to approximately 1601b (72–7 kg) live weight, iso-nitrogenous (16% crude protein) maize-based diets (as wet mashes with 2:1 ratios of water to dry food) containing 0–15%, 0–22% or 0–29% tryptophan and either 0–85% or 0–97% lysine. Overall, for the period in its entirety and in the period from the start to 110 lb (50–0 kg) live weight, the diets containing 0–22% and 0–29% tryptophan gave a similar performance. Together they gave a significantly superior performance compared with that obtained from the diets containing 0–15 % tryptophan. Pigs fed the diets containing 0–85 % lysine converted their food better and grew faster than pigs fed the diets containing 0–97 % lysine. These differences were significant (P <0–05) for both parameters in the period from 110 lb (50–0 kg) live weight to the finish of the experiment at 1601b (72–5 kg) live weight and significant (P <0–05) for efficiency of food conversion in the overall experimental period.
The growth, composition and nutrient uptake of spring wheat: Effects of fertilizer-N, irrigation and CCC on dry matter and N, P, K, Ca, Mg, and Na
Authors: Gasser J. K. R. , Thorburn M. A. P.
Published: March 2009

Kloka spring wheat grown on a sandy-loam soil was given 50, 100, 151 or 201 kg N/ha as fertilizer, was irrigated during drought or not irrigated, and was sprayed with CCC (2-chloroethyltrimethylammonium chloride) or not sprayed. Samples, taken approximately weekly from brairding to heading and less frequently to maturity measured the production of dry matter. The dried samples were analysed for percentage N, P, K, Ca, Mg and Na and the uptakes of these were calculated to measure the effects of treatments on the composition of the crop and the weights of nutrients it contained.

Increasing amounts of fertilizer-N up to 151 kg N/ha increased the maximum weight of straw without irrigation and up to 201 kg N/ha with irrigation; similarly, maximum weights of ears were with 100 kg N/ha without irrigation and 151 kg N/ha with irrigation. The maximum weight of straw was at flowering and of ears at maturity. Irrigation increased yields of straw and ears, more with the two larger than with the two smaller amounts of fertilizer-N. Spraying with CCC decreased the yield of straw, and did not affect the yield of ears.

Increasing amounts of fertilizer-N increased percentage nutrients in the green crop and in the straw, and of N, P and Mg in the ears. Effects of irrigation and spraying with CCC on composition differed between nutrients and between ears and straw, sometimes increasing, sometimes decreasing, and sometimes having no effect, on percentage in dry matter.

Increasing fertilizer-N increased the maximum weight of N, K, Ca and Na in the crop. P and Mg increased with up to 151 kg N/ha, but was no more with 201 kg N/ha. Maximum weight of N, P, Mg and Na was found at or near maturity, of K at heading and of Ca at flowering.
Variability of yields of cereal varieties in U. K. trials
Authors: Patterson H. D. , Silvey Valerie , Talbot M. , Weatherup S. T. C.
Published: March 2009

This paper presents the results of analyses of yield variability in more than 500 trials of varieties of spring oats, spring wheat, spring barley and winter wheat. A table of critical percentage yield differences has been constructed for guidance in planning future series of trials.
Effects of seed size and spacing of seed tubers and stems on yields of early and canning potatoes
Authors: Proctor J. M. , Smartt A.
Published: March 2009

An experiment comparing most combinations of six seed sizes and four spacings between seeds to give a range of common seed rates, was repeated for 3 years with the eultivar Ulster Prince. For the earliest harvest, total yield was reasonably related to seed rate, but for subsequent harvests the yield response was more closely related to number of stems; this pattern was more pronounced in yields of the canning grade.
Immediate behavioural consequences of fostering 1-week-old piglets
Authors: Horrell R. I.
Published: March 2009

Twenty-four sows and their 4- to 7-day-old litters were observed in batches of four for approximately 2h to ascertain piglet teat preferences and timings of suckling periods. In each batch, two litters were then selected to have two piglets exchanged between them while the other two remained intact as controls. In the subsequent 3 h, sows with fostered piglets initiated significantly more suckling periods than controls; but many were disturbed at an early stage and only 35% of such periods resulted in milk letdown (compared with 93% in controls). Many sows displayed aggression specifically towards fostered piglets. Many fostered piglets showed signs of distress and attempted to escape. Fostered piglets were significantly more likely to take 10 sec or more from the start of suckling to approach the udder, and less likely to be sucking at milk letdown. Many of these effects were greater when piglets had to compete with a resident piglet with the same teat preference and all were still evident in the third of the three observation hours.
The effect of moving colonies of honeybees to new sites on their subsequent foraging behaviour
Authors: Free J. B.
Published: March 2009

1. Groups of colonies have been moved to crops requiring pollination: group A, before any blossom appeared; group B, when 5–15% of the crop was in flower; and group C, when the crop was in full flower, and the amount which the colonies of the different groups visited the crop was determined. The results tend to show that colonies of group B visited the experimental crop more than colonies of group A, thus supporting recommendations that colonies should not be moved to a crop requiring pollination until it has started to flower, so that the bees will not have previously become conditioned to visiting other flower species in the locality.

2. When a colony is moved to a new site its foragers tend to visit species they have visited previously, and the amount of a particular pollen that a colony collects at a new site is sometimes related to the amount of it the colony collected before it was moved.

3. The conclusion of previous workers that different colonies utilize the local flora in different ways have been confirmed. Different colonies vary greatly both in the number and kind of species they visit and in the extent to which they visit the same species. Although the extent to which colonies visit certain species tends to be related to the extent they have visited them previously, exceptions often occur.
A radiographic study of early skeletal development in foetal sheep
Authors: Wenham G.
Published: March 2009

Observations were made on high resolution radiographs of foetal sheep, from ewes slaughtered at 7-day intervals from 34 to 55 days after mating, to examine the onset of ossification of some of the major components of the axial and appendicular skeleton. There were 83 foetuses measured, retrieved from 24 Finnish Landrace × Polled Dorset Horn ewes mated to Suffolk rams. The litters comprised five sets of twins, eight of triplets, seven of quadruplets, three of quintuplets and one set of sextuplets.

Half of the ewes were subjected to a 50% reduction in food on the 28th day of gestation, but this was considered not to have affected skeletal growth and development.

There were major changes in skeletal mineralization from one slaughter date to the next, particularly between 34 days, when no skeletal elements were detectable, and 41 days, when components of the skull, thorax, fore and hindlimbs were clearly seen. There were some differences in the number of primary centres present both within and between litters of the same gestational age. The mineralized shaft of the fibula was seen in 30/35 of the foetuses at 41 days, but only in 9/25 at 55 days; other transient centres were also observed.

Changes in the linear dimensions of six limb bones were measured and the mean values are presented in tabular form.
Influences of diet and body condition on the nitrogen utilization in the cow
Authors: Paquay R. , De Baere R. , Lousse A.
Published: March 2009

The dietary and individual factors influencing the utilization of digestible nitrogen in the dry cow were studied with numerous rations fed to Friesian cows kept in metabolism stalls.

Urinary nitrogen excretion and nitrogen balance were above all influenced by the level of digestible nitrogen intake. They are also correlated to metabolizable energy and digestible potassium intakes.

Endogenous urinary nitrogen, estimated by extrapolation, was 30·6 mg N/kg body weight/d or 0·169 W0·73 g/d with the rations meeting approximately the energy maintenance requirements of the cow.

The changes in diet accounted for 80% of the variability of nitrogen balance.

A method was worked out for calculating the body condition of the cow from the live-weight variations.

The changes in body condition accounted for 11% of the variability of nitrogen balance.
Cation activity ratios in the soil solution and availability of potassium to rice in a submerged soil
Authors: Pasricha N. S.
Published: March 2009

The activity ratios of potassium in dynamic equilibrium with a submerged soil planted with rice were determined fortnightly for 10 weeks. The simple activity ratio, aK(aCa + aMg)-1, and the modified activity ratio to include the activity functions of Fe2+ and Mn2+ as aK/(aCa+ aMg)½ + B(aFe)½ + C(aMn)½, gave linear relationships when plotted against the change in exchangeable K content of the soil. The modified activity ratio of potassium correlated better with potassium concentration (r = 0·91) in and potassium uptake (r = 0·84) by rice than the simple activity ratio (r = 0·86 and 0·81 respectively).

Submergence for 6 weeks almost doubled the potential buffering capacity of potassium, PBCK, showing that the submerged soil sustained a low level of potassium in the soil solution for a long time.

A negative intercept of the plot of equilibrium labile K, Kel, on the ‘quantity’ axis, against the modified activity ratio showed that there is some non-labile K which equilibrates with the soil solution during growth. The value of this intercept (3·40 mequiv/kg soil) is a measure of non-labile K.
The relationship between number of seeds and the frequency of ovule fertilization in field beans (Vicia faba L.)
Authors: Rowland G. G. , Bond D. A.
Published: March 2009

A correlation coefficient of r = 0·985 (P < 0·01) between the number of fertilized ovules at each cultivar-ovule position (Rowland, Bond & Parker, 1983) and the number of mature seeds for each cultivar-ovule position indicated an extremely close relationship between fertilized ovules and seed set in four field bean cultivars. This suggests that unreliability in seed yield in field beans could be due to variability in frequency of fertilization as well as in frequency of abortion of seeds and of whole pods.

Frequency of ovule abortion occurred differentially among cultivars and this abortion rate varied according to the flowering node and flower position within a raceme. Under stress conditions single-seeded pods were preferentially aborted. The data suggest that a way to increase the average number of seeds per pod is through increased frequency of ovule fertilization.
Maintenance requirements of phosphorus and absorbability of dietary phosphorus in sheep
Authors: Field A. C.
Published: March 2009

The factorial approach to the determination of the dietary requirements of macroelements is a two-stage process; in the first the net requirements are estimated and in the second, the fractional absorption of the dietary mineral is used to convert net to dietary requirements (Agricultural Research Council, 1965). At the first stage the maintenance component is allotted a fixed value, so that estimated dietary requirements are directly proportional to absorbability of the element.
Confirmation of the presence of calcium oxalate crystals in some tropical grasses
Authors: McKenzie R. A. , Schultz K.
Published: March 2009

During the last decade, a calcium (Ca) deficiency syndrome, nutritional secondary hyperparathyroidism (NSH), has caused lameness and bone lesions in horses grazing certain tropical grasses in Australia. These grasses contain over 0·5% total oxalate (Walthall & McKenzie, 1976; Blaney, Gartner & McKenzie, 1981a). Blaney et al. (1981a) and McKenzie, Blaney & Gartner (1981) carried out mineral balance experiments with horses fed tropical grass hays or diets with added soluble potassium oxalate. Their results suggested that NSH was caused by the oxalate in the grasses preventing the absorption of Ca. They also suggested that the Ca in the grasses may already be in the form of the insoluble calcium oxalate (Ca(COO)2) salt and thus unavailable to grazing horses. Blaney, Gartner & McKenzie (1981b) subsequently demonstrated that horses could not absorb significant amounts of Ca from Ca(COO)2 crystals added to their diet.
The emergence of maize from field sowings in Great Britain: I. The effect of date of sowing on the extent and speed of emergence of different varieties
Authors: Bunting E. S. , Willey L. A.
Published: March 2009

Between 1953 and 1955 a series of field experiments have been carried out in Great Britain to assess the effect of sowing date on the extent and the rate of emergence of a number of varieties of maize.

The range of sowing dates was from late March till May. Records were kept of the soil temperatures, these will be reported later, and in certain experiments the water content of the soil was maintained at field capacity. In all experiments a northern flint variety and a southern dent variety were sown, in the first year only flint × dent hybrids were also grown.

There was an increase in final emergence with the later sowing dates. The northern flint varieties were superior to the southern dent varieties, while the flint × dent hybrids occupied an intermediate position. The lower final emergence of the southern dent variety was most marked at the earlier sowing dates.

Differences between varieties in the speed of emergence, taken as the number of days from sowing until half of the surviving seedlings had emerged, was observed at several centres. The open-pollinated varieties usually emerged more slowly than the flint × dent hybrids. There was a very marked difference between early- and late-sowing dates in speed of emergence.

It was possible in the second year to compare seed of high quality with that of low quality as determined by the ‘cold test’ of germination capacity. The lowquality seed gave greatly reduced final emergence, the experiments stressing the need for the adoption of a standard ‘cold test’ for maize seed, especially of that intended for sowing in north-western Europe.

The high final emergence of the northern flint varieties suggest that a gene source for resistance to soil pathogen attack is readily available. The possibilities in north-western Europe for expansion of growing grain maize would be greatly strengthened by development of varieties capable of growth at low temperatures. The experiments suggest that until such varieties are available little advantage in time of emergence will be gained by sowing maize before late April in Britain.
Nitrogen fixation in field beans (Vicia faba) as affected by population density, shading and its relationship with soil moisture
Authors: Sprent Janet I. , Bradford Alison M.
Published: March 2009

N fixation data, estimated by the acetylene reduction technique and by total N content are given for the field experiments reported by Sprent, Bradford & Norton (1977).

Maximum potential acetylene reducing activity per plant varied little from year to year. At low population densities a maximum rate of activity was observed shortly after flowering. As density increased this maximum became less pronounced and environmental factors (such as water supply) exerted increasing effects on activity. Shading prolonged activity and delayed nodule senescence.

Total plant N continued to increase almost to seed maturation. As plants aged, the acetylene reduction technique progressively underestimated N accumulation. Maximum Nfixed/ha/year was over 600 kg. Itis concluded that the potential for N fixation in this crop is sufficient to sustain high yields.
Resistance to bean yellow mosaic virus in Phaseolus vulgaris
Authors: Walkey D. G. A. , Innes N. L. , Miller Ann
Published: March 2009

Accessions of green and dry-podded Phaseolus vulgaris beans were tested for resistance to seven isolates of bean yellow mosaic virus (BYMV) originating from a wide geographical area. Based on their level of resistance, the beans could be divided into four groups, (i) accessions with a high level of resistance to most BYMV isolates; (ii) accessions containing previously known sources of resistance in germplasm derived from the cv. Great Northern, which were mainly susceptible to the BOS 25 isolate, but had high levels of resistance to most other isolates; (iii) and (iv) groups showing increasing levels of susceptibility with the accession Red Mexican (common) the most susceptible bean tested. The seven BYMV isolates induced distinct reactions when inoculated to arange of plant species, indicating that they possessed different pathogenicity genes.
A note on an alternative technique for measurement of area of midside patch in wool growth studies
Authors: Butler L. G.
Published: March 2009

The ‘conventional’ method of measuring the area of a wool sample patch involves the direct in situ measurement of the patch dimensions while in the field using callipers (Turner et al. 1953). This procedure is time consuming and expensive in terms of labour required. In an attempt to reduce the cost and increase the speed of the procedure in the field a new method was devised and tested.
The Effect of Sowing Date on the Yield and Yield Components of Spring Oil-Seed Rape
Authors: Scarisbrick D. H. , Daniels R. W. , Alcock Mary
Published: March 2009

Three spring oil-seed rape cultivars were drilled on five dates during 1979 and 1980. Delayed drilling (1) reduced seed yield, (2) increased the main stem contribution to seed production, and (3) increased the percentage of damaged pods at harvest. The results indicated that cultivars similar to those used in this trial should be drilled between the 3rd week of March and mid-April.
The influence of pesticides and herbicides on the growth and virulence of Fusarium solani f. sp. phaseoli
Authors: Mussa A. E. A. , Russell P. E.
Published: March 2009

Three herbicides, Treflan, Basagran and Avadex BW and three pesticides, Metasystox 55, Nicotine and Hostathion stimulated the growth of Fusarium solanif. sp. phaseoli in culture and increased the virulence of this pathogen on Phaseolus vulgaris. The implications of these results to the chemical treatment of this crop are discussed.
Interpretation of the faecal excretion patterns of solute and particle markers introduced into the rumen of sheep
Authors: Faichney G. J. , Boston R. C.
Published: March 2009

A two-pool + time delay model was used to analyse ideal marker concentration patterns generated, using an interactive computer simulation program, from data for the mean retention times of [51Cr]EDTA and [103Ru]phen in the reticulo-rumen, abomasum and caecum-proximal colon and the transit times of these markers through the omasum, small intestine and distal large intestine of sheep. Although providing a reasonably close fit to the generated data, the fitted curves showed small but systematic deviations, indicating that the model does not consistently characterize the kinetics of the markers in the ruminant gastro-intestinal tract.

When the components of the two-pool model were correctly identified, predicted rumen mean retention times (MRT) were within – 1 to + 13% of the observed values. However, identifying the component with the longer MRT as the rumen resulted in up to 2·6-fold overestimation (17·5 v. 6·77 h). The model underestimated the time delay and the overall MRT. It is suggested that the correct identification of the two components can be achieved by the simultaneous use of a solute-and a particulate-phase marker because, in ruminants, they do not behave independently in the caecumproximal colon.
The cytogenetics of the differences between someSecalespecies
Authors: Riley Ralph
Published: March 2009

1. The seed of crosses ofSecale cerealewithS. montanumandS. dalmaticumgerminated only whenS. cerealewas the seed parent.

2.S. cerealewas found to differ fromS. montanumandS. dalmaticumby two large translocations involving three pairs of chromosomes, and a small translocation involving a fourth pair. The fertility of theF1plants was low, and in ear morphology and perennial habit they were similar to theS. montanumandS. dalmaticumparents.

3.S. montanumandS. dalmaticumwere found to be similar in gross chromosome structure and their hybrids were phenotypically intermediate and fertile.

4. TheF2of the crossS. cereale x S. dalmaticumconsisted of three types, in terms of chromosome structural condition and plant morphology, those like one or other parent and those like theF1.

5. The genetic and evolutionary significance of this situation is discussed, together with the problem of the fixation of translocations in populations.
The experimental production of ‘green yolks’ by the oral administration of sodium copper chlorophyllin
Authors: Worden Alastair N. , Bunyan J. , Davies A. W. , Kleissner M.
Published: March 2009

1. A condition that appears to be identical with ‘green yolks’ as observed in natural cases has been reproduced by the oral administration in gelatin capsule of from 250 to 1000 mg. sodium copper chlorophyllin 100% daily for 4 days upwards to Light Sussex hens in second lay.

2. Following suitable extraction procedures the presence of a chlorophyll derivative has been determined spectrophotometrically in the affected yolks.

3. Quantities of sodium copper chlorophyllin of the order of 1 mg. have been recovered from affected yolks.

4. It is considered that the passage of chlorophyll to the yolk indicates that intestinal absorption has occurred.
Field nitrates in the Gezira soil. II
Authors: Jewitt T. N.
Published: March 2009

The yields of cotton from five three-course rotations are given; they show marked seasonal variations, the variations of the different rotations being in close accord with one another. The average yields of the rotations are related fairly closely to the average soil nitrates; in individual years this is not so, though considerable responses to nitrogenous manuring are always obtained on Gezira soil.

The distribution of nitrate in Gezira soil shows an unusual accumulation at depth; though cotton roots can reach the zone of accumulation, the variability of nitrate at these depths renders it impossible to relate changes to uptake. The figures show that under growing cotton the whole of the upper 4 ft. of soil can have low nitrates (of the order of 1 p.p.m.). Unless the roots obtain nitrate from the fifth and sixth feet accumulations the plants must be taking up nitrate as fast as it is formed, and the nitrate-supplying power of the soil must be of first importance. Figures are given showing differences in nitrification in soil from the different rotations.

The effect of heavy nitrogenous manuring on soil nitrate is shown to be largely confined to the year of application, and no accumulations could be demonstrated. The average recovery of added nitrogen in this experiment is only of the order of 10%. The yields of the heavily manured treatments show the same violent fluctuations as do the unmanured treatments.

In the three-course rotation experiment surface nitrates in August and September in the wider rotations are strongly negatively correlated with the rainfall of the period 1 July to 15 August. Over the period July to September the distribution of nitrates in the upper 2 ft. of the profile changes; there are differences between the rotations in this respect.
Milk production from subtropical non-dairy sheep. 2. Method of measuring
Authors: Aboul-Naga A. M. , El-Shobokshy A. S. , Moustafa M. A.
Published: March 2009

Milk yield of 240 single-suckled ewes from Rahmani, Ossimi and Barki subtropical non-dairy Egyptian sheep, in addition to 64 twin-suckled Rahmani ewes, was estimated over two lambing seasons using three methods of measuring, i.e. lamb-suckling (plus residual milk), oxytocin technique and hand milking.

For single-suckled ewes, the oxytocin technique resulted in higher (P < 0·05) estimates of milk yield during the first 4 weeks of lactation than lamb-suckling. However, over 12 weeks of lactation the two methods showed closely similar estimates. Hand milking produced 31·6% less milk than the other two methods.

For twin-suckled ewes, the lamb-suckling method produced significantly (P < 0·05) higher estimates than the oxytocin technique. Estimates obtained by hand milking were 65·2 and 50·8% less than that of the other two methods, respectively.
Studies of the growth and development of winter-heading cauliflowers
Authors: Wurr D. C. E. , Kay Rosemary H. , Allen E. J. , Patel J. C.
Published: March 2009

The winter-heading cauliflower varieties St Thomas, St Gwithian, St Agnes, Janavon, St Hilary, St Buryan, BB74605, St David and St Keverne were grown at Trefloyne, Tenby for 3 years from 1977 to 1980. Plants of all varieties were sampled periodically to determine the rate of curd expansion, the final number of leaves, the time of curd initiation, and the distribution of dry matter within the plant.

The patterns of development of leaf area were similar in all varieties. Dry-matter distribution was similar for all varieties except for root growth; later-maturing varieties had a greater dry weight of root and a higher proportion of the total dry matter as root, than early varieties. Early rates of curd growth declined with later-maturing varieties and it is suggested that there may be a relationship between the time of curd initiation, root growth and the rate of curd growth.

The mean total number of leaves formed before curd initiation varied from 49 to 102 depending on the variety and year. The earliest varieties St Thomas and St Gwithian took co. 120 days to reach 50% curd initiation and matured in 6–7 months from sowing while the late variety St Keverne took over 200 days to reach 50% initiation and more than 11 months to mature. The time interval between 50% initiation and 50% maturity increased with later-maturing varieties but on the basis of accumulated day degrees > 6 °C it declined with later varieties. The latter also matured more uniformly than earlier varieties when using an accumulated day-degree scale > 6 °C as a time scale.

The results suggest that the low temperature threshold below which curd induction occurs may vary with variety. There was also evidence that the base temperature for curd growth is lower with later-maturing varieties.
Measurement of endogenous allantoin excretion in sheep urine
Authors: Antoniewicz Anna M. , Pisulewski P. M.
Published: March 2009

Urinary allantoin, an end product of purine base metabolism, originates in sheep from three possible sources: exogenous, purine bases of rumen microorganisms and feed purines and ureides, and endogenous, purines catabolized in tissue turnover. Earlier studies suggested that nucleic acid purines of rumen micro-organisms may be a predominant source of urinary allantoin (Antoniewicz, Heinemann & Hanks, 1979, 1981).
Influence of foliar fertilizers on the toxicity and tolerance to some insecticides in the cotton leafworm
Authors: El Attal Z. M. , Moustafa Omayma K. , Diab Samiha A.
Published: March 2009

The joint action of two pyrethroid insecticides with several foliar fertilizers against the fourth-instar larvae of Spodoptera littoralis was determined. The rate of development of tolerance throughout three successive generations to insecticides alone and their combinations with fertilizers was also assessed. The results indicate that the toxicity of the insecticides tested was greatly enhanced by using fertilizers in admixture with each of them. Moreover, the inclusion of such fertilizers in spray emulsions slows down the development of tolerance to both insecticides. The synergistic action of fertilizers and the decrease in the induction of tolerance to insecticides can be attributed to the presence of inorganic ions and to decreasing the pH of both acidic experimental insecticides resulting in increasing the penetration rate of the internal membranes of the cotton leafworm.
The effects of the timing of management actions on the performance of a grassland sheep flock
Authors: Speedy A. W. , Black W. J. M. , Fitzsimons J.
Published: March 2009

A production system is defined which involves the production of lambs from crossbred ewes kept in a cool, temperate grassland environment at an altitude of 250–300 m. Within the production system, an investigation was carried out on the effect of the timing of weaning, pre-mating treatment (flushing) and concentrate feeding before lambing in a flock of 180 Border Leicester (♂) × Scottish Blackface (♀) ewes maintained for a production span of four lamb crops. Weaning treatment had no significant effects on changes in live weight or body condition score. Pre-mating treatment affected live weight and condition at mating. It did not affect the number of lambs born but had a significant effect on the subsequent birth weight of twin lambs in the 1st year it was applied but not thereafter. The timing of introduction and total quantity of concentrate feed affected the birth weight of lambs from ewes at their first lambing (24 months old) but not subsequently. There were no long-term effects of treatment on ewe survival or on the production characters measured. The results are discussed in relation to the seasonal patterns of grass supply and the normal limits of commercial practice. In this study, when grass and forage were in reasonable supply, pre-mating management and concentrate feeding were not critical to ewe performance. Only in circumstances of an unusual grass shortage and also in young ewes did these factors have significant effects on performance.
A comparison of the growth and development of biculm wheat lines with freely tillering cultivars
Authors: Marshall C. , Boyd W. J. R.
Published: March 2009

The growth, development and grain yield of two low-tillering lines of wheat of Israeli origin were compared with those of two freely tillering Australian wheat cultivars (Gamenya and Egret) in field plots. The majority of individuals from the low-tillering selections were uniculms or biculms. Detailed observations were made on the main shoot of the biculms. There was no difference in the duration of primordia production by the main shoot apex between genotypes but the rate of initiation of spikelet primordia in the lowtillering lines was significantly greater than that of the tillering cultivars and this resulted in a large ear with more spikelets. The rate of leaf appearance was very similar in all genotypes but the later-appearing leaves of the biculms were very large in comparison with those of the cultivars. The majority of the biculms produced the tiller in T3 position. At maturity the main shoot and tiller of biculm individuals produced 60 and 40% respectively more dry weight than the equivalent shoots of the tillering cultivars. The total biomass per plant of the biculms was similar to that of Egret but less than that of Gamenya. The grain yield of the main shoot of the biculms was 50% greater than that for the tillering varieties and this was associated with an increase in the number of grains per ear as there was little difference in grain size. In the biculm a high proportion of the spikelets in the mid part of the main shoot ear produced five grains; grains from basal florets were significantly larger than those of upper florets mainly because they had a longer duration of growth. Overall the grain yield of the two tillering cultivars, either per plant or per metre of row length, was approximately 30% greater than that of the low-tillering selections. The greater growth of the main shoot axis in the biculms therefore did not compensate for the grain contributed by the tillers of the freely tillering cultivars.
Intercropping of upland rice with blackgram [Vigna mungo (L.)]
Authors: Sengupta K. , Bhattacharyya K. K. , Chatterjee B. N.
Published: March 2009

To increase the productivity of fields growing direct-seeded upland rice, which usually gives low yields because of weed competition, unsatisfactory establishment and exposure to intermittent drought, an experiment on intercropping of rice with blackgram was conducted in two seasons under rainfed conditions on a sandy loam soil. Blackgram, when intersown simultaneously in one row in every 30 cm wide space left between the stand of 10 cm apart paired rows of rice, reduced the yield of rice by 1·64 t/ha. When one row of blaokgram was intersown, 21 days after sowing of rice (after completing weeding) between the paired rows of rice, rice yield was reduced by only 0·24 t/ha compared with solecropping of rice with weeding. This system provided mean yields of 2·48 t/ha of riceand 0·95 t/ha of blackgram. The price of blackgram being high, it showed a mean monetary advantage of Rs. 2373/ha over sole cropping of rice. The blackgram reduced the weed population appreciably.
Fate of fertilizer zinc in a black soil (Vertisol)
Authors: Sarkar A. K. , Deb D. L.
Published: March 2009

Rice is the major food crop grown on black soils of southern India and these soils have problems of high zinc fixation due to high clay content, high pH and dominance of smectite minerals causing zinc deficiency problems. The addition of zinc fertilizers to these soils has often been ineffective as the element is transformed to unavailable forms particularly under flooded rice conditions. Studies on the distribution of fertilizer zinc among different pools of soil zinc (Viets, 1962) could be useful in formulating methods of zinc application for higher efficiency of utilization. An attempt was therefore made to study the transformations of added zinc in soils in field experiments conducted in a rice-rice sequence involving the use of 65Zn as a tracer.
Metal concentrations in sludges and soil from a long-term field trial
Authors: McGrath S. P.
Published: March 2009

Metal contents are reported of the soils from a field experiment in which two rates of various organic manures, including sewage sludge and sludge compost, were applied from 1942 to 1961. Changes in the concentrations of some elements in the sludges during the 20 years are also presented.

The percentage recoveries of the added metals Zn, Cu, Ni, Pb, Cd and Cr in the topsoil varied from 71 to 96%. In 1960, extractability of the metals from the soils by 0·05 M-EDTA was 50% of the aqua regia-soluble total metals. This figure did not vary greatly with metal or with the type of organic manure that was applied.
Effect of salt, alkali and zinc on iron equilibrium in submerged soils
Authors: Sadana U. S. , Takkar P. N.
Published: March 2009

In a pot experiment the effect of salt (EC 5, 10 and 20mmhos/cm at 25 °C), alkali (ESP 10, 20 and 40) and Zn (lOmgZn/kg soil) on Fe equilibria in submerged soils was studied. The required salt and alkali concentrations were obtained by adding calculated amounts of NaCl and NaHCO3 respectively to Rohi sandy loam (Typic Ustifluvent). The soil solutions drawn anoxically by gravity were analysed for pH, pE, EC and Fe. As the EC increased, pH and pE of the soil solution decreased and Fe concentration increased at all the stages of submergence. ESP had the opposite effect. Addition of ZnSO4 in combination with EC and ESP treatments further decreased pH and pE and increased Fe concentration; however, its effect was more pronounced in the former treatments. In spite of wide variation in pH, pE and Fe concentration in soil solution, the values of the expressions pE – pFe2+ + 3pH, pE – 1·5 pFe2+ + 4 pH and pE + pH were nearly constant and close to the standard values of 17·9, 23·3 and 7·3 for Fe(OH)3 – Fe2+, Fe3(OH)8 – Fe2+ and Fe(OH)3 – Fe3(OH)8 systems after 1, 14 and 14 days of submergence, respectively. Addition of ZnSO4 did not have an appreciable effect on these systems in salt- and alkalitreated soils.
Relationship of stalk morphology and chemical composition to lodging resistance in maize (Zea mays L.) in a rainforest zone
Authors: Esechie H. A.
Published: March 2009

Field and laboratory studies were carried out in 1981 and 1982 to investigate the relationship of stalk morphology and chemical composition to lodging resistance in maize in the rainforest zone of Nigeria.

Morphological characters correlated with lodging were plant height, diameter and length of basal internode, thickness of rind and weight of 5 cm basal section. Lodging was negatively correlated with grain yield, and with the percentages of total nonstructural carbohydrate, protein and potassium in the stalks. Premature stalk senescence and rot were common in varieties susceptible to lodging. Lodging had no relationship with leaf area and number of days from sowing to flowering.
Hydrodynamics and the germination of oil-seed rape pollen
Authors: Corbet Sarah A. , Plumridge Janette R.
Published: March 2009

Pollen grains of oil-seed rape, Brassica napus, were germinated in vitro in conditions in which water activity could be closely controlled. Germination success depended on the humidity experienced by the grains before contact with the germination medium, as well as on the osmolarity of that medium. On contact with the germination medium the grains swelled and then shrank. Each suffered one of three fates: it burst, or it germinated without bursting, or it did neither, remaining unchanged. Grains that were to remain unchanged swelled least. Those that were to burst swelled most. Those that were to germinate were intermediate.

Some implications for in vitro germination studies are discussed.