bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and yield of sugar beet on contrasting soils in relation to nitrogen supply: I. Soil nitrogen analyses and yield
Authors: Last P. J. , Draycott A. P.
Published: March 2009

Nine field experiments with sugar beet in 1968–70 tested eight amounts of nitrogen fertilizer (0–290 kg N/ha) on a shallow calcareous loam (Icknield Series), on a deep sandy loam (Newport Series) and on a heavy clay loam (Evesham Series). Top soils and subsoils, sampled during autumn, winter and spring before the experiments, were analysed by several methods for available and potentially-available nitrogen. The largest increases in potentially-available mineral-nitrogen shown by incubation occurred in the calcareous loams every year in both top soil and sub-soil, and the sandy loam, particularly the sub-soil, generally produced least. Attempts to forecast the optimum nitrogen fertilizer dressing from the soil analyses were moderately successful, the best technique being anaerobic incubation of air-dry soil; the date of sampling had little effect. The optimum dressings were always between 0 and 125 kgN/ha, the calcareous loams generally needing least nitrogen fertilizer and the loamy sands most.
The relation between animal gain and stocking rate in grazing trials: an examination of published theoretical models
Authors: Sandland R. L. , Jones R. J.
Published: March 2009

Jones & Sandland (1974) examined the validity of the linear model for gain per animal on stocking rate. This paper examines the alternative models of Conniffe, Browne & Walsh (1970, 1972) and a proposed extension of the model of Owen & Ridgman (1968). Discrepancies between these models and the linear model are studied in detail.

Under specified conditions these models are shown to be very close to the linear model. It is concluded, from the earlier work of Jones & Sandland (1974) and these results, that the empirically justified simple linear model has the advantage of being much easier to fit as well as embodying (approximately) the theoretical advantages of these conceptually superior models under a range of assumptions.
Effect of rumen protozoa on dietary lipid in sheep
Authors: Abaza M. A. , Akkada A. R. Abou , El-Shazly K.
Published: March 2009

Washed suspensions of mixed rumen protozoa readily hydrogenated fatty acids in cottonseed, soya bean and corn oils in addition to free oleic and linoleic acids. Protozoa belonging to the familyOphryoscolecidaeappeared to account for almost all the activity of mixed protozoa, protozoa of the familyIsotrichidaepossessing little or no ability to hydrogenate the added substrates. The hydrogenation of oleic acid was markedly increased by Fe and Mn. The addition of starch cellulose, urea and sodium formate greatly stimulated hydrogenation of oleic acid by rumen protozoa. Glucose, casein, ammonium sulphate, L-cysteine andn-valeric acid had no or little effect on extent of hydrogenation.

When suspensions of mixed protozoa were incubated in a buffer solution, an increase in iodine value was observed. The desaturation in the protozoal cells was appreciably increased by DL-methionine and was not influenced by L-cysteine. No desaturation activity by the pure suspensions ofOphryoscolecidaeorIsotrichidaewas observed.

The presence of protozoa in the rumen of sheep greatly increased the levels of saturated fatty acids over those in the ciliate-free animals. The concentrations of saturated fatty acids in the plasma of faunated sheep were significantly higher than those in the same animals after the removal of rumen ciliate protozoa.
Growth, development and nutrient uptake in pigeonpeas (Cajanus cajan)
Authors: Sheldrake A. R. , Narayanan A.
Published: March 2009

The growth and development of two early (Pusa ageti and T-21) and three mediumduration (ST-1, ICP-1 and HY-3C) cultivars of pigeonpea (Cajanus cajan (L.) Millsp.) were compared at Hyderabad, India, in 1974 and 1975; in 1976 cv. ICP-1 was studied. The pigeonpeas were grown on a Vertisol and on an Alfisol. The crop growth rate in the first 2 months was low. The maximum rate of 171 kg/ha/day was found in the fourth month of growth of cv. ICP-1 on Alfisol. The early cultivars, one of which (cv. Pusa ageti) was morphologically determinate, and the other (cv. T-21) indeterminate, did not differ in the proportion of dry matter partitioned into seeds. The mean dry weight of the ab ove-ground parts of the medium cultivars on Vertisol in 1975 was 8·45 t/ha, including 2·23 t/ha of fallen plant material. The mean harvest index (ratio of grain dry weight to total plant dry weight) of these cultivars was 0·24 excluding fallen material and 0·17 taking fallen material into account. Starch reserves were present in the stems during the vegetative phase, but disappeared during the reproductive phase. In 1974 the maximum leaf-area index on Vertisol was 3 and on Alfisol 12·7. The net assimilation rate tended to decline throughout the growth period, but in the medium cultivars increased at the end of the reproductive phase, probably because of photosynthesis in pod walls and stems.

In 1974 and 1975 the growth of roots and distribution of nodules in Vertisol was investigated by means of soil cores. Roots extended below 150 cm and root growth continued during the reproductive phase. Most nodules were found within the first 30 cm of soil, but some were found below 120 cm. In cv. T-21, grown in brick chambers150 cm deep, at the time of harvest about three-quarters of the mass of the roots was found in the first 30 cm, and the shoot:root ratio was around 4:1.

In 1975 the mean uptake of nitrogen by the medium cultivars on Vertisol was 120 kg/ha, including 34 kg/ha in fallen material. In 1976 the uptake of nitrogen by cv. ICP-1 was 89 kg/ha on Vertisol and 79 kg/ha on Alfisol, including 32 and 23 kg/ha respectively in fallen material. Nitrogen uptake continued throughout the growing period. The percentage of nitrogen in stems and leaves declined as the plants developed and there was a net remobilization of nitrogen from these organs. The pattern of uptake and remobilization of phosphorus resembled that of nitrogen. In 1976 the total uptake of phosphorus by cv. ICP-1 on Vertisol was 5·8 kg/ha and on Alfisol 5·0 kg/a.

The relatively low yields of pigeonpeas result from a restricted partitioning of dry matter into pods, which may be related to the plants' perennial nature.
Studies on reproduction in prolific ewes:5. The accretion of nutrients in the foetuses and adnexa
Authors: McDonald I. , Robinson J. J. , Fraser C. , Smart R. I.
Published: March 2009

The concentrations of dry matter, crude protein, fat and ash and of Ca, P, Mg, Na and K were determined for 22 sets of twin foetuses, 33 of triplets and 11 of quadruplets of known gestational ages within the range 55–145 days. In addition, determinations were made of the concentrations of dry matter, crude protein, fat and ash in their associated placentae and empty uteri, and of dry matter, nitrogen, energy and ash in the foetal fluids. The dry matter, crude protein and fat concentrations in the placentae increased with foetal age and decreased with increasing litter size. Ash concentrations were unaltered. There was no effect of litter size or foetal age on the concentration of nutrients in the empty uteri. Dry matter and nitrogen concentrations in the fluids increased with foetal age but were independent of litter size, whereas ash concentrations increased with litter size but not with age.

The form of the mathematical model for foetal growth is considered in relation to the estimation of rates of accretion and the estimation of the differences in composition to be expected between foetuses that are heavy and others that are light relative to their age. When the weights of the foetal constituents were fitted by Gompertz equations extended to include foetal weight as an allometric term, the effects of litter size on foetal composition could be estimated from the foetal weights for each size of litter. Concentrations of dry matter and of most constituents in the foetuses became less as numbers of foetuses increased, irrespective of stage of gestation.

A description of the changing composition of the growing foetuses was provided by specific growth rates calculated from the fitted equations. With minor exceptions, derived estimates of foetal concentrations of each constituent were found to agree quite well with most previously published estimates for ovine foetuses, but similar agreement on daily accretion rates was not to be expected in view of the sensitivity of such estimates to the choice of model for foetal growth. Rates of accretion in the gravid uterus increased up to about 5 weeks before parturition and tended to level off thereafter, but most of them still increased slightly over the last 2 weeks, even in ewes bearing triplets or quadruplets. Taking account of the changes in the maternal body of the ewes, it was concluded that although the prolific ewes incurred a substantial energy deficit, and could not have consumed sufficient of the diet to avoid this, their intakes in late pregnancy were nevertheless adequate to support the high rates of accretion of protein and of minerals in the gravid uterus.
Quantitative digestion of fresh herbage by sheep:V. The digestion of four herbages and prediction of sites of digestion
Authors: Ulyatt M. J. , Egan A. R.
Published: March 2009

The extents and sites of digestion of organic matter (OM), and its constituent watersoluble carbohydrates, organic acids, pectin, cellulose, hemicellulose and crude protein have been studied in sheep prepared with re-entrant duodenal cannulas and fed four fresh herbage diets, Ruanui perennial ryegrass, Tama Westerwolds ryegrass, Pitau white clover and Fakir sainfoin, at each of two levels of intake.

The water-soluble carbohydrate, organic acids and pectin of all diets were almost completely digested within the rumen. Some 10% of water soluble carbohydrate reached the duodenum on each diet, though this may not have been of dietary origin. Only on legume diets, where pectin concentration was higher, did measurable amounts of pectin reach the intestine, accounting for some 5% of the pectin.

Hemicellulose and cellulose digestibilities differed between diets, being lowest for sainfoin, and next lowest for clover. Between 79 and 94% of digestible hemicellulose was digested in the stomach, but diet and intake had no significant effect on this partition. Of the digestible cellulose, 87–97% was digested in the stomach.

Digestibility of N was lowest for sainfoin and highest for Tama ryegrass. There were no significant differences between herbage species or intake in the percentage of digested N digested in the stomach or intestines. The tannin contained in sainfoin had no effect on nitrogen digestion.

Data from this and other studies reported in the literature were examined as a basis for establishing prediction equations whereby the partition of digestion of the major carbohydrate and nitrogenous constituents in stomach and intestines might be estimated from data obtainable from standard digestibility trials. Regressions were developed for predicting the amounts of OM, cellulose, and hemicellulose digested in the stomach. There are not yet enough suitable data available to predict the amount of nitrogen entering the small intestine.
Phorate-resistant mutant strains of chick pea (Cicer arietinumL.)Rhizobiumsp. growth and their compatibility in symbiotic nitrogen fixation
Authors: Rai R. , Sinha R. B. , Prasad V.
Published: March 2009

Chick peaRhizobiumstrain RG3 was treated with 30 μg/ml of N-nitrosoguanidine and two mutants isolated were resistant to 2000 μg phorate/ml yet retained the capacity to form nodules. On the basis of number of nodules, their dry weight, N2ase activity, total pyridine nucleotides and active iron contents, mutant strains G11 and G26 were found to be equally effective with and without phorate and resulted in significantly greater grain yield.
Recovery of ryegrass species from drought
Authors: Norris I. B. , Thomas H.
Published: March 2009

The effect of drought on the growth and subsequent recovery of container-grown perennial, Italian and hybrid ryegrass plants was assessed in a glasshouse. Dry-matter production and percentage of water-soluble carbohydrates were measured, and nondestructive measurements of growth components (leaf extension, leaf appearance and tillering) were made.

Drought had an effect upon all the variables recorded. Italian ryegrass was most severely affected by drought in terms of tillering, leaf extension and subsequent recovery. Selecting for improved recovery growth was considered to be of more economic importance than selecting for improved growth during drought.

It was concluded that subjecting pot-grown plants to drought, although in many ways unrealistic, was a very useful technique when screening a large number of different genotypes for drought tolerance and recovery.
A model for estimating soil moisture deficits under cereal crops in Britain:1. Development
Authors: Francis P. E. , Pidgeon J. D
Published: March 2009

A new and detailed model, involving meteorological, crop and soil variables, is proposed to provide daily estimates of moisture deficits in soils under cereal cropping in Britain. The model incorporates developments in the calculation of potential evapotranspiration specifically for cereal crops. Four processes of loss of water are considered, namely drainage, evaporation of free water from the crop canopy, evaporation from the soil surface and transpiration by the crop. Thus the model is applicable at all stages of the cropping cycle. Above-ground and root system development of the crop are modelled and available and extractable water capacities of a wide range of soils are estimated. Thus the demand for water and its availability are varied with crop species, stage of development and soil type as well as with meteorological variables.

The calculation of water losses is not dependent on arbitrary assumptions about the division of losses between the four processes considered or between different horizons of the soil.

Extreme simplicity of input data requirement has been maintained. The model has been programmed in FORTRAN, and is compatible with Meteorological Office data archives.
The Contribution of Clay and Organic Matter to the Base Exchange Capacity of Soils
Authors: Williams Rice
Published: March 2009

1. The total exchangeable bases, clay, total carbon and carbon oxidisable by 4 per cent, hydrogen peroxide, have been determined for a number of carbonate soils.

2. Assuming soils containing excess of carbonate under natural conditions to be base saturated, equations have been derived connecting exchange capacity with clay and (a) total or (b) “oxidisable” carbon content.

3. When the organic matter of these soils was assumed to have a constant base exchange capacity, no correlation was found between the exchange capacity of their clay fractions and either their silica-alumina or their silica-sesquioxide ratios.

4. Carbonate soils whose exchangeable base content was appreciably less than the calculated values were found to contain either small amounts of calcium carbonate (< 1 percent.), or the bulk of it was present in coarse form.
High moisture maize grain for growing pigs: some effects on acceptability, digestibility, nitrogen retention and performance of physical form and tocopherol supplementation
Authors: Lawrence T. L. J.
Published: March 2009

In seven experiments involving a total of 300 Large White pigs, moist maize preserved with propionic acid was compared, at dietary inclusion levels of approximately 85%, in whole (W) or rolled (R) forms with maize taken from the same samples, dried and then ground (DrG). Propionic acid lost in drying was returned to give identical levels in all three forms. In the first two experiments the moist maize contained 37·4% moisture, was included in diets to which no synthetic tocopherol was added and had been in storage for approximately 1 year when drying was effected and experiments on acceptability (using 54 pigs offered diets based on the three forms simultaneously in Expt 1) and digestibility and nitrogen retention (using 12 pigs on two occasions in Expt 2) were started. The moist maize used in Expts 3, 4, 5, 6 and 7 contained 45·8% moisture and was dried 2 months after harvesting. Between this time and 12 months post-harvesting experiments were made, with all diets supplemented with 10 g/t δ-α-tocopherol, on digestibility and nitrogen retention (using 18 pigs on two occasions in Expt 3) and performance between approximately 20 and 72 kg live weight (using three sets of 48 ad libitum group-fed pigs per set in Expts 5, 6 and 7). A further performance study (Expt 4) of factorial design and conducted over a similar live-weight range, between 2 and 5 months post-harvesting, investigated, using 72 individually but restrictedly fed pigs, responses from R, W and DrG based diets with or without the addition of 10 g/t δ-α-toeopherol.

Four months post-harvesting the δ-α-tocopherol levels of the moist and dried maize used in Expts 3–7 were 0·5 and 7·2mg/kg D.M. respectively. Five-six months post-harvesting the peroxide values of the other extractable fat of the moist maize markedly increased. In Expt 1 the diet based on the DrG form was eaten to the virtual exclusion of the diets based on the other two forms but performance responses were poor and symptoms (partially confirmed) of a tocopherol deficiency apparent. However, in Expt 4 there were no significant differences in response to the zero and 10 g/t δ-α-tocopherol supplementation. Overall, the DrG and R forms of maize gave similar utilization and growth (up to 8 months post-harvesting) responses. Compared with these responses those from the W form were inferior (in most cases significantly). When the moist cereal in R and W forms was fed after 8 months of storage (Expts 1, 6 and 7) the daily intakes of D.M. and induced growth responses obtained were lower than those obtained from the DrG form.
Response of wheat (Triticum aestivum L.) to graded doses of P and N on soils of different P and organic carbon fertility classes under rainfed conditions
Authors: Meelua O. P. , Bishnoi S. R. , Randhawa N. S. , Sharma K. N.
Published: March 2009

Results of experiments made on cultivators' fields under rainfed conditions show that response to P application decreased as available P status of soil increased. The response to N application was higher in low organic carbon soils than in medium organic carbon soils with all levels of application and the difference in response widened with increase in N level.
Seasonal variation in some characteristics of seminal plasma of Sudan Desert sheep in the tropics
Authors: Galil K. A. A. , Galil A. K. A.
Published: March 2009

Some androgen-dependent constituents of seminal plasma of Sudan Desert rams were measured during the hot dry summer, the hot rainy season and the winter under tropical conditions in the Sudan. Higher concentrations of both fructose and citric acid were obtained between July and October during the rainy season and low values between January and April during winter, with marked monthly and seasonal variation in both characters. Considerable monthly variation in the hydrogen-ion concentration of semen was obtained with lower values between August and January and higher values between February and July. The androgenic status of the animals appears not to be decreased during the hot weather, but no explanation can be offered for the decrease during the winter.
The effect of fertilizer nitrogen, phosphorus and potassium on the calcium, magnesium and phosphorus status of pasture cut for silage
Authors: Rodger J. B. A.
Published: March 2009

Physiological problems in some Fife dairy herds were thought to be associated with mineral imbalance in grass cut for silage. Consequently trials at two sites were conducted to study the effects of three levels of nitrogen and phosphorus and two levels of potassium on yield and composition of pasture cut for silage.

Nitrogen increased yield of herbage and reduced its clover content whereas phosphorus and potassium had little effect on yield or clover content. Herbage clover content and calcium concentration declined over the period of the experiment. Mean concentrations of calcium, magnesium and phosphorus were 5·8, 1·7 and 3·4 g/kg respectively. Concentrations of these minerals varied more with time of cutting and with season than with level of applied phosphorus and potassium.

Nitrogen tended to reduce calcium concentration in mixed herbage and to increase magnesium concentration in the grass component; it did not affect herbage phosphorus concentrations, but narrowed the calcium-phosphorus ratio in the second cuts. Applied phosphorus increased herbage phosphorus concentration only at the site with the lower soil phosphorus status. Potassium tended to reduce magnesium concentration in clover and, at one site, in mixed herbage; it also tended to reduce herbage phosphorus concentrations in second cuts.

Mineral uptake was increased by applied nitrogen. Mean annual uptake of calcium magnesium and phosphorus was 34, 10 and 20 kg/ha respectively.

The effects of treatments on concentration and balance of these minerals are discussed in relation to ruminant requirements and maintenance of suitable levels of the minerals in the soil.

It is concluded that normal applications of NPK fertilizer are not detrimental to satisfactory mineral balance in pasture.
Fattening studies with cross-bred (European×Zebu) bulls: 1. Performance on diets of native hay and concentrate
Authors: O'Donovan P. B. , Gebrewolde A. , Kebede B. , Galal E. S. E.
Published: March 2009

Two group-feeding and one individual-feeding experiments were made for 112 and 182 days, respectively, with 76 cross-bred and eight Zebu bulls. Simmental, Friesian and Jersey sire breeds were mated to three Ethiopian Zebu breeds, namely Boran, Horro and Barca, while Zebu bulls were included for comparison purposes in Expt 3. The trials were conducted in confinement at Holetta Research Station, located at 2400 m elevation and having a mean maximum temperature range of 18·7–24 °C. In the group-feeding trials (Expts 1 and 2) a common diet was fed, consisting of native hay (30%) molasses (20%) and a concentrate supplement. In the third experiment, two diets containing 30 and 50% native hay were supplemented by concentrate and fed individually to eight Simmental and eight Friesian cross bulls, while eight Zebus served as a control.

The average daily gains, feed intake and conversion did not differ markedly between Simmental and Friesian crosses, but lower values were generally found for Jersey crosses. Cross-breds outgained Zebus, consumed more feed and converted it more efficiently to live-weight gain. Performance differences were noted between the Zebu breeds as well as some evidence of sire × dam breed interactions. Significantly higher gains were achieved with the low than with the high roughage diet.
The effects of dietary starch and fibre on thein vitrorates of lipolysis and hydrogenation by sheep rumen digesta
Authors: Gerson T. , John A. , King A. S. D.
Published: March 2009

The objective of this work was to investigate the effects of changing proportions of readily fermentable carbohydrate and fibre in the diet on the rates of lipolysis and fatty acid hydrogenation by sheep rumen digesta. Three experiments were carried out using rumen-fistulated Romney wethers. In the first experiment rumen digesta from one sheep on a high-fibre diet was incubatedin vitrowith [1–14C]linoleic acid and 0, 0·1, 0·2 and 0·5% sucrose. It was found that sucrose increased the rate of hydrogenation of linoleic acid by up to 40%.

In the second experiment five rumen-fistulated Romney wethers were fed five diets according to a latin-square experimental design. These diets had decreasing proportions of fibre (42·8–19·5%) and increasing proportions of starch (12·2–35·7%). Lipolysis and hydrogenation rates decreased significantly with decreasing fibre content which was reflected in the amounts of stearic and octadecenoic acids in the rumen digesta.

In the third experiment sheep were fed the high-fibre diet used in the first experiment and the rumen digesta incubated in the presence of 0, 0·15, 0·45, 0·75 and 1·50% starch. Lipolysis rates increased but no effect of added starch on hydrogenation was observed.

It was concluded that the short-term addition of energy to the rumen digesta increases lipolysis and hydrogenation rates. However, long-term replacement of fibre by starch results in a reduction of these rates.
High biomass genotypes in spring barley
Authors: Hanson P. R. , Riggs T. J. , Klose S. J. , Austin R. B.
Published: March 2009

Three experiments were carried out to measure grain and biomass yields of spring barley breeding lines and varieties. Leaf diseases were controlled by applying proprietary fungicides and in some treatments plants were supported by nets to prevent lodging. The trials, grown in 1982 and 1983, compared the grain and biomass yields of 14 breeding lines and two varieties with and without support. In a third experiment, comparing three lines and the varieties Triumph and Egmont, all the plots were supported and in addition each experimental plot was flanked by guard plots of the same genotype to minimize inter-plot competition.

In the supported plots of all three experiments, three breeding lines, SB 543–3, SB 71–2 and HSB 258–93 produced significantly greater biomass yields than the mean of the varieties Triumph and Egmont. All three breeding lines were taller and had lower ratios of grain to grain + straw than the controls. Measurements were made of the accumulation of dry matter, chlorophyll content at anthesis and date of ear emergence but no single factor could be identified which was associated with increased biomass in these lines.

The grain yield of the semi-dwarf, lodging-resistant variety Triumph was reduced by an average of 0·24 t/ha by the support treatment compared with the non-supported control. The results from the third experiment suggested that the yield of Triumph was reduced by inter-plot competition by about 10% in relation to the other entries in the trial.

It is suggested that the high biomass lines identified here could be used as parents in a breeding programme to produce varieties with high yield if this high biomass could be combined with a high ratio of grain to above-ground dry-matter yield.
Effect of preceding season cultural practices on mustard (Brassica juncea Czern) under semi-arid rainfed conditions of north-west India
Authors: Giri G. , Saran G.
Published: March 2009

A field trial was made for 3 years at the Indian Agricultural Research Institute, New Delhi under semi-arid rainfed conditions to study the effect of the preceding season cultural practices on mustard and to assess the possibility of double cropping, and the results are discussed. Preceding season cultural practices, i. e. ploughing in fallow or growing cow pea for fodder or mung for grain (both short-duration crops) increased the yield of the mustard crop compared with no tillage or growing pearl millet in preceding season. Yield of mustard following tillage, fodder cow pea or mung with mulch was similar; hence it is concluded that double cropping is possible under such conditions instead of conventional tillage-mustard, monoeropping practice. It is also concluded that frequent ploughings could be greatly reduced to give few but more effective cultivations, but more research into reducing cultivation during the preceding season should be carried out.
The climatic potential for field hay drying in north-west Europe
Authors: Thompson N. , Barrie I. A. , Harvey L. D. J.
Published: March 2009

A model of a drying swath has been developed and used with 20-year long meteorological data sets from 32 sites in north-west Europe to provide an objective assessment of the influence of weather on field hay drying. The model considered the swath in terms of its bulk properties but incorporated the effects on swath drying of soil evaporation and stubble transpiration: delays in swath drying caused by interception of rain or dew were calculated explicitly.

A cutting season from May to September was assumed, and results given in terms of the number of daily cuts reaching various moisture contents in less than 10 days, and especially those reaching 25% (dry-weight basis) within 5 days so that dry-matter losses were relatively small, and immediate long-term storage was possible. Rainfall amounts on the faster-drying swaths were usually less than 1 mm. A large inter-annual variability in hay-drying prospects was demonstrated, even at sites with fairly good climates for drying on average. The most favourable conditions for field drying were shown to occur substantially earlier in the cutting season at maritime sites than at those with a more continental climate. Conditioning of the swath allowed more cuts to dry to a prescribed moisture content, but with the penalty of larger average rainfall on the swath, and consequent loss of quality.
Evaluation of technique for screening Fe-efficient genotypes of rice in calcareous soil
Authors: Singh B. P. , Singh R. A. , Sinha M. K. , Singh B. N.
Published: March 2009

Lime-induced Fe chlorosis is often a severe problem on calcareous and saline alkali soils. Symptoms of apparent Fe deficiency and responses to its application on several field crops have been observed under such soil conditions (Indian Council of Agricultural Research, 1980–81; Sakal, Singh & Singh, 1982, 1983). Rice varieties exhibit variable reaction to Fe stress when cultivated as an upland crop especially at seedling stage in the nursery (Patel, Ramakrishanyya & Patel, 1977; Singh et al. 1984). Plant analysis is one of the accepted tools for diagnosing nutritional disorders. Chlorotic plants often contain more total Fe than the green plants (Katyal & Sharma, 1.980; Voigt et al. 1982). In order to overcome this elusive behaviour of Fe it has been suggested that in place of total Fe the plants should be analysed for active Fe or dilute HCl-extractable Fe (Machold & Stephen, 1969). Iron is important for chlorophyll biosynthesis and is linked with a number of enzyme systems. The change in the activities of the enzymes has beenused as a yardstick to distinguish Fe deficiency in plants (Del Rio et al. 1978). Wallace (cf. Katyal & Sharma, 1980) and Patel et al. (1977) suggested analysing the plants for that fraction of Fe which correlates well with occurrence of chlorosis.
Estimation of amounts of microbial and dietary nitrogen compounds entering the duodenum of cattle
Authors: Smith R. H. , McAllan A. B. , Hewitt D. , Lewis Patricia E.
Published: March 2009

Young steers with rumen and simple duodenal cannulas were given diets of approximately equal amounts of flaked maize and hay (A) or of flaked maize and straw supplemented with decorticated groundnut meal (DCGM) (B), fishmeal (C), heated soya-bean meal (D) or raw soya-bean meal (E) or of dried grass (F). A cow with rumen and re-entrant duodenal cannulas was given diets of hay and dairy cubes.

Some steers received doses of32P-labelled inorganic phosphate twice daily with their concentrate feed. This led to small diurnal variations in inorganic P–32P specific activity but at similar daily sampling times the32P specific activity in rumen bacterial nucleic acids reached a steady state after dosing for about 4 days. Contributions of microbial-N to non-ammonia-N (NA-N) entering the duodenum were then estimated by comparing nucleic acid32P/NA-N ratios in related samples of rumen bacteria and duodenal contents. Similar estimates were made in these and other animals using α-, ε-diaminopimelic acid (DAP) and ribonucleic acid (RNA) as bacterial markers.

Estimates for steers given diets A, B, C and F based upon ‘32P-labelled RNA nucleotides’ were, on average, 85% of those based upon total RNA. The differences were attributed mainly to the latter being elevated by the presence of small amounts of dietary RNA. When RNA-based estimates of the proportion of microbial-N in NA-N in duodenal contents for these and other steers which were nearly free of protozoa were multiplied by 0·85 (‘adjusted RNA’) the values were, on average, similar to those based upon DAP. Similar estimates for the cow based upon ‘adjusted RNA’ measurements were, however, about twice those based upon DAP, probably because the cow contained a high protozoal population and the DAP based, method did not account for protozoal N.

For some steers total flows at the duodenum of organic matter (OM), microbial-N (mean based upon ‘adjusted RNA’ and DAP) and residual food N were estimated by reference to chromic oxide. Average values for g microbial-N synthesized/kg OM truly digested in the rumen for the different diets ranged from 15 to 22 (mean 20). Mean degradabilities of food N (residual food N at duodenum/N intake) were 0·57, 0·71, 0·71, 0·70 and 0·84 for diets A, B, C, D and E respectively. No differences between diets were significant atP< 0·05.
The growth of maize
Authors: Iremiren G. O. , Milbourn G. M.
Published: March 2009

Total dry-matter yield of maize silage rose asymptotically as density was increased up to 17 plants/m2. Over the range 11–17 plants/m2, which is generally higher than is used in the U.K., the increase in yield was 1–1·6 t dry matter/ha which can justify the higher seed cost and although there was no adverse affect on time of maturity the risk of lodging increased at the highest density. During the harvest period whilst whole crop dry-matter percentage was rising from 23 to 28%, the ear dry-matter content rose steadily from 29 to 35%, whereas the leaf and stem dry-matter content remained essentially constant and only dried out at a later stage after a frost.

Caldera 535 had a higher leaf area index and net assimilation rate than the earlier variety Julia which it outyielded by 15%. The additional yield was mainly stem tissue and the greater vegetative production caused an 11-day delay in reaching the silage stage of maturity (25% crop D.M.). NO differences occurred between density treatments and varieties in the forage quality components considered, namely percentage drymatter digestibility, modified acid-detergent fibre, crude protein and ash. Thus in U.K. conditions, total dry-matter yield exerts an overriding influence on the yields per unit area of these quality constituents. This contrasts with reports from the U.S.A. in which a reduced grain/stover ratio adversely influences silage quality.

Removal of the whole ear (including husk and rachis) at an early stage in ear development resulted in a 50% reduction in the final dry-matter yield. In the earless plants, leaf area and net assimilation rate was lower, but the dry-matter content of the leaves and stem was considerably higher, and a marked purple coloration developed indicative of excess starch concentration. These results emphasize the need in maize silage not only for an adequate leaf canopy, best obtained early in the growing season by using high planting density and subsequently by using late maturing varieties, but also for sufficient sink capacity in the ear as well as in the stem fraction.
Game domestication for animal production in Kenya: shade behaviour and factors affecting the herding of eland, oryx, buffalo and zebu cattle
Authors: Lewis J. G.
Published: March 2009

Studies on night-enclosed eland, oryx, buffalo and cattle in south eastern Kenya showed that the animals spent only a short time each day in the shade; the mean duration was not more than 2 h/day for any species.

All four species actively sought shade in the middle of the day. The time spent in the shade by the three indigenous species was significantly related to activity times and environmental heat load; that of cattle was not.

In general the time spent in the shade by the four species could be related to characteristics of their coat.

The captive animals at Galana spend less time in the shade than their free-living counterparts. This is thought to be partly due to the need of wild animals to reduce their total body water turnover rate and for captive animals to spend more time feeding during the day.

The inter-individual distances (IID) maintained by eland, oryx and cattle and the synchronization of the activity of these three species and buffalo were also studied.

Eland maintained the largest mean IID (13·7 m) while those for oryx (6·5 m) and cattle (4·0 m) were considerably less. Calculations showed that herds of 250 eland might occupy an area of approximately 5 ha, oryx 1 ha and cattle would occupy 0·5 ha. The IID of all three species were significantly related to activity and the IIDs of eland and oryx were significantly related to meteorological factors. The differences in the IIDs of the three species were thought to be due to differences in feeding strategies and the length of time for which cattle have been domesticated.

For all species feeding was well synchronized, but walking, idling and shade behaviour were not. Although only one activity was well synchronized it was the most time consuming one. The lack of synchrony in other activities did not pose a great problem in the management of the relatively small herds being studied. Lack of synchrony, however, might cause a problem if the size of the herds were substantially increased.
The estimation of the nutritive value of feeds as energy sources for ruminants and the derivation of feeding systems
Authors: Blaxter K. L. , Boyne A. W.
Published: March 2009

The authors regret the following error: On p. 53, equation (11) is incorrect and should read:
Effects of crop husbandry and growing conditions on storage losses of Pentland Crown potatoes
Authors: Wilcockson S. J. , Allen E. J. , Scott R. K. , Wurr D. C. E.
Published: March 2009

Over five growing seasons (1976–80) experiments were carried out using at least three contrasting sites per season to study the relationship between growing conditions and storage losses in Pentland Crown potatoes. Crops were harvested by hand and storage was carried out in a single environment over a period of 6–7 months without sprout suppressants. The range in growing conditions was great and reflected in the pattern of leaf growth and range in yields of the stored crops (30–90 t/ha). Crops from Tenby (S. W. Wales) produced the most consistent and frequently the highest yields and usually lost the least weight during storage. Although the range in total weight loss over all experiments was large from 5·4 to 16·3%, treatment effects were much smaller than in field growth and yield. Delaying the date of harvest usually increased weight loss and tubers harvested in early August stored at least as well as late-harvested tubers. Tubers harvested without prior defoliation stored as well as tubers harvested on the same day from crops defoliated at least 2 weeks previously. Lengthening the interval from defoliation to harvest usually increased weight loss in storage. Although the tubers were hand harvested effects on saleability were found at the end of storage and there was no evidence that earlier harvesting, which may involve some loss of field yield, would result in any loss of saleable yield out of store.

The results provided no evidence to support the widely-held view that the suitability of a tuber for harvesting improves during maturation associated with natural or imposed crop senescence. It is therefore suggested that the use of the term maturity be avoided as it is wholly unhelpful in studies of the relationship between field growth and storage losses in potatoes.
The effect of organic phosphates on the drying rate of grass leaves and dry-matter losses during drying
Authors: Harris C. E.
Published: March 2009

Tri-w-butyl phosphate has previously been shown to increase the drying rate of cut grass leaves. It also markedly inhibited respiration and thus reduced loss of dry matter during drying. In the work reported here, some other commercially available phosphate esters were tested for the same effects, except for the inhibition of respiration. Four mixtures of ethoxylated phosphate esters increased the drying rate of excised S. 24 perennial ryegrass leaves, and three of these also reduced the loss of dry matter during drying.

The results suggest the possibility of devising single chemical treatments for both increasing the drying rate and reducing the respiration rate of forage crops conserved by drying in the field. The potential advantages of such treatments, together with the difficulties of realizing these advantages in practice, are briefly discussed.
Leaching of potassium in illitic soil profiles as influenced by long-term application of inorganic fertilizers
Authors: Singh Bijay , Sekhon G. S.
Published: March 2009

The correlation between sorption and mobility of potassium in illitic soils has been used to compare K leaching in profiles under different fertilizer treatments in longterm experiments. Estimates of potassium saturation of the cation exchange capacity in 15 cm soil layers to a depth of 225 cm indicated maximum leaching of K in unfertilized soils. Application of N, P and K increased K uptake by plants, reduced K saturation and thus its leaching.
The relationship between phosphate response and base saturation in acid soils
Authors: Birch H. F.
Published: March 2009

In three groups of field experiments totalling fiftysix observations phosphate responses were found to be very significantly and inversely related both to the percentage saturation of the b.e.c. and exchangeable calcium as a percentage of exchangeable calcium plus hydrogen. The availability of the native soil phosphate was significantly and directly related to these values. The relationships between phosphate response or availability and the amounts of acid-soluble, adsorbed and water-soluble phosphate in the soils were much less conclusive.

In acid soils considerable amounts of phosphate can be retained in a plant-available form associated with exchangeable bases, mainly calcium. Since practically all the soils from the field experiments lay within the range pH 4·7–6·3, it is believed that this form of phosphate is operative in these soils. The presence of such phosphate in the soil is, however, a function of the degree of base saturation in so far as this governs (probably through its influence on soil pH) the equilibrium distribution of the native soil phosphate between the available base-linked (saloid-bound) form and the less available colloid-bound form. With decreasing pH and base saturation increasing amounts of colloid-bound phosphate are formed at the expense of the saloid-bound phosphate. The degree of base saturation is therefore directly related to phosphate availability and, consequently, inversely related to phosphate response.

In view of the significant regressions obtained, and the association of the exchangeable bases with a specific form of available phosphate, it is suggested that until methods are worked out for determining the amount of saloid-bound phosphate exchangeable base data may be used for assessing phosphato availability and response in acid soils. This method is contrasted with the more conventional methods of determining acid-soluble and adsorbed phosphates which are not always specific regarding tho form of phosphate extracted and the values for which, since they may represent the sum of a number of forms of different availabilities, aro difficult to interpret.
Effects of dietary deficiencies of energy, protein and calcium on the pregnant ewe
Authors: Sykes A. R. , Field A. C.
Published: March 2009

Scottish Blackface ewes were used to investigate the effect of protein deficiency during pregnancy on serum albumin, globulin, transferrin and plasma urea concentrations. Twenty-eight sheep were offered one of two iso-caloric diets in amounts which maintained energy intake at levels comparable to those found in hill sheep during winter. For half of the sheep (HP group) the crude-protein concentration was 11·8% and for the remainder (LP group) 6·0% in the dry matter. A further six sheep (group CL) were offered a diet containing 16·0% crude protein in amounts which prevented undernutrition. Concurrent changes in plasma volume and in certain serum proteins during pregnancy were determined in a second experiment.

Serum globulins were not affected by protein intake and fell from 44·5 to 30·7 mg/ml during pregnancy. This was attributed mainly to a 30% increase in plasma volume which occurred during pregnancy.

Serum albumin concentrations at the end of pregnancy were 29·3, 22·0 and 17'7 mg/ml and serum transferrin concentrations 400, 307 and 300 mg/100 ml in the CL, HP and LP groups respectively. Initial mean albumin and transferrin concentrations were 28·0 mg/ml and 383 mg/100 ml respectively. The usefulness of the parameters as indices of the protein status of pregnant ewes was discussed.

Plasma urea N concentrations were related to the current protein intake of the animal. Mean values during late pregnancy were 26·0, 7'4 and 4·0 mg urea N/100 ml in the CL, HP, and LP) groups respectively. Limitations as to its usefulness were discussed.
The interaction of wheat genotypes with a specific factor of the environment
Authors: Easton H. S. , Clements R. J.
Published: March 2009

Several alternative statistical approaches to the analysis of genotype-environment interactions are summarized, and their inter-relationships are presented mathematically and graphically. An experiment was designed to test the ability of these analyses to satisfactorily describe genotype-environment interactions and to locate genotypes causing or contributing significantly to such interactions in a situation where environments differed in only one factor, i.e. soil nitrogen status.

Twenty-five lines of wheat were grown at each of 5 levels of applied nitrogen (0–270 kg N/ha) in a sandy, nitrogen-deficient soil, and their grain yields and yield components (ears per unit area, grains per ear, weight per grain) were determined. Designating the nitrogen levels as ‘environments’, linear yield responses, and deviations from linear responses, of individual wheat entries to environment mean yield were calculated according to the various statistical procedures previously outlined. The results suggested that the linear response to environment mean yield was similar for all wheat entries. However, further inspection of the data revealed that the responses of eight entries to environment mean yield departed significantly from linearity. Although several analyses satisfactorily identified these aberrant entries, classifying them as ‘unstable’, it was concluded that the degree of departure from linearity of response was not an adequate measure of instability. Furthermore, as previously suggested by Knight (1970), it was confirmed that the relative ranking of an entry for yield stability according to such a concept varied according to the average response of the group of entries with which it was being compared.

The general effects of applied nitrogen on yield components were to increase the number of ears and the number of grains per ear, and to decrease grain weight. However, only the first of these effects occurred consistently for all entries. The number and weight of individual grains per ear varied with the nitrogen treatment, often unpredictably, in a complex pattern which differed significantly between entries.
A radiographic study of skeletal growth and development in the pig. Temporal pattern of growth
Authors: Wenham G. , Fowler V. R. , McDonald I.
Published: March 2009

The skeletons of 34 pigs killed at a number of weights from birth to 120 kg were examined radiographically. Data were also used from radiographs of 83 foetuses of different ages.

Estimates were made of the age of appearance of various ossification centres and measurements taken of the diaphyseal length and breadth. A chart is given showing the age of appearance of ossification centres. Exponential equations in which the independent variate was time were fitted to both pre- and post-natal linear measurements. These equations were used to calculate the age at which each of the measurements attained a given proportion of the post-natal asymptote. The development of the pig's skeleton is discussed in relation to that of other species. Attention is drawn to the possibility that the uncritical use of accepted terminology such as early and late maturing may tend to obscure an understanding of the manner in which certain components of the skeleton develop.