bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of random F3 families for cross prediction in spring barley
Authors: Thomas W. T. B.
Published: March 2009

Random F3 families from six crosses typical of those being made in a spring barley breeding programme at the Scottish Crop Research Institute were used to rank the crosses on the basis of their predicted probabilities of exceeding a given standard for a number of characters. The predicted rankings were then compared with the observed rankings of the crosses based on observations of random inbred lines from the same crosses. The agreement between predicted and observed rankings was very good for single characters and good for bivariate combinations of the characters. The agreement for the bivariate combination of height and single plant yield was exact and the combination also appeared to be capable of accurately ranking crosses on the basis of height and plot yield.

The practical considerations of using such a cross prediction technique in a cereal breeding programme are discussed. Results from this experiment suggest that single plant measurement could be replaced by measurements on progeny rows, thereby saving considerably on labour. Predictions could just be made on the most important characters in the breeder's model for the early identification of the best crosses but this is still an advance on the approach of making many crosses and assessing relatively few selections from each cross in yield trials.
The yield of durum wheats released in Mexico between 1960 and 1984
Authors: Waddington S. R. , Osmanzai M. , Yoshida M. , Ransom J. K.
Published: March 2009

Two trials designed to measure progress in the yield of durum wheat cultivars released in Mexico by the Institute Nacional de Investigaciones Agrícolas over the period 1960–84 were grown in the Yaqui Valley, Sonora, Mexico, during the 1983–4 and 1984–5 cropping seasons. The trials compared grain yield, above-ground biomass, harvest index (ratio of dry grain yield to dry above-ground biomass), yield components, grain-growth rates and phenological characters for eight key cultivars and the modern advanced line, Carcomun ‘S’, when grown at a high level of agronomic inputs and management.

The grain yield of durum wheat was estimated to have risen for 25 years of breeding from 3·70 to 8·40 t/ha. The estimated average annual rates of increase in grain yield for the periods 1960–71 and 1971–85 were 251 and 121 kg/ha respectively. Grain yield improvements were based on a linear increase in the number of grains/m2 over the 25-year period, the result of more grains per spikelet. An improved above-ground biomass at maturity was a feature of the two modern genotypes, Altar 84 and Carcomun ‘S’. Harvest index increased with each new cultivar up to the release of Mexicali 75 in 1975, but thereafter the higher grain yields achieved with the modern genotypes were not associated with a higher harvest index. Thousand-grain weight remained steady for the released cultivars but fell slightly for the advanced line Carcomun ‘S’. Improvements in yield were not associated with a longer cropping cycle.

It is concluded that a breeding strategy combining selection for morphological characters thought to confer high yield potential, such as a more erect leaf posture and high number of grains per spikelet, with selection for grain yield per se has been successful in improving the grain yield of durum wheats adapted to north-west Mexico. Improvements have come not only in the size of the grain sink and the efficiency of assimilate partition to grain but also in the biomass produced above ground.
Studies of resource use and yield of mustard and chickpea grown in intercropping systems
Authors: Kushwaha B. L. , De R.
Published: March 2009

A study was made under rainfed (unirrigated) conditions in a subtropical and semi-arid region of northern India during the winter (October–March) seasons of 1980–1 and 1981–2 to evaluate the growth, resource use and seed yield performance of four intercropping systems, namely mustard alone, ⅔ mustard +⅓ chickpea, ⅓ mustard + ⅔ chickpea and chickpea alone grown at 7·5, 15·0, 22·5 and 30·0 plants/m2.

The total economic productivity of intercrop systems was greater than that of either component grown alone. The components of seed yield (number of primary and secondary branches, number of pods, seed weight per plant and weight of seed) increased in mustard where intercropped but the opposite occurred in chickpea. These growth attributes were decreased with an increase in plant population density. The two crop species needed an individual density less than their sole crop optima to form an optimum density when intercropped. A mixture of ⅓ mustard + ⅔ chickpea appeared to be the best system for the rainfed conditions in which these experiments were made and produced greatest yield advantage.

Chickpea grown in ⅓ mustard + ⅔ chickpea combination had greater nodulation with higher dry weight per nodule. A greater leaf area index (LAI) for both the crop species was noted in ⅓ mustard + ⅔ chickpea mixture than were found in other systems. The maximum LAI of mustard and chickpea was attained at 60 and 120 days after sowing respectively and this may be why a lower proportion of mustard plants in the intercrop was more advantageous.

A combination of ⅓ mustard + ⅔ chickpea removed more nitrogen from the soil, had better water use efficiency and comparatively less soil moisture depletion than the sole crop. Soil nitrogen utilization and soil moisture depletion were less at higher densities.
Thyroxine concentration in maternal and foetal plasma during pregnancy in Australian feral goats
Authors: McDonald B. J. , Stocks D. C. , Connell J. A. , Hoey W. A.
Published: March 2009

Gestational age-related changes in plasma free thyroxine (FT4) concentration in maternal and foetal goats were determined for 65–140 days of pregnancy. The placental permeability to maternal thyroxine (T4) and iodine (I) during the last trimester of pregnancy was evaluated.

The presence of T4in foetal circulation at 65 days' gestation, the absence of a significant correlation between maternal and foetal levels and the absence of any transplacental diffusion of125I–T4showed autonomous foetal thyroid function during pregnancy in goats. Significantly low maternal FT4was measured at 95 and 110 days' gestation (32·7 and 31·5 pmol/1 respectively). Plasma concentration increased to 48·6 pmol/1 at day 125 then fell before parturition to a level similar to that of non-pregnant goats (41·9 pmol/1). In contrast, foetal FT4increased with gestational age to 110 and 125 days when levels of 64·0 and 59·1 pmol/1 respectively were greater than those at all other ages, suggesting that the foetal hypothalamic-pituitary-thyroid is functioning at a higher rate than the maternal system around this time. This was supported by increased foetal thyroid affinity for I when compared with the maternal thyroid at 110–140 days' gestation.

A significant cubic relationship between foetal FT4and gestational age was established.
Influence of particle size and surface area onin vitrorates of gas production, lipolysis of triacylglycerol and hydrogenation of linoleic acid by sheep rumen digesta orRuminococcus flavefaciens
Authors: Gerson T. , King A. S. D. , Kelly Kathleen E. , Kelly W. J.
Published: March 2009

Particulate fractions prepared from meadow hay, ranging in size from 0·1 to 2 mm, were incubated with rumen digesta from four cannulated Romney sheep fed the same hay. The rates of gas production, lipolysis of corn oil and hydrogenation of linoleic acid were measured.

The rate of gas production per g fermentable particles (FP) was approximately 30% lower with 1–2 mm than with the 0·1–0·4 mm particles. However, per m2surface area the rate for the larger particles was found to be approximately 600% greater.

The rates of lipolysis of triacylglycerols and hydrogenation of linoleic acid were respectively 25 and 60% higher per g FP and 1100 and 1200% higher per m2FP surface area with the 1–2 mm particulate fraction.

The same hay particulate fractions were incubated with pure cultures ofRuminococcus flavefaciens, since this organism is active in both lipid metabolism and cellulose fermentation. The rate of gas production and the number of organisms adhering to the particles were determined.

The effects of particle size on gas production were similar to those found when incubations were carried out with rumen digesta. Per g FP the rate was 40% lower with 1–2 mm than with 0·1–0·4 mm particles. However, per m2surface area the rate was found to be approximately 450% greater with the former.

It was further found that although the density of the bacterial population on 1–2 mm particles was 600% higher than on the 0·1–0·4 mm particles, the rate of gas production per 109bacteria remained unchanged.

We conclude that per m2surface area fermentation, lipolysis and hydrogenation were more rapid with particles ranging from 1 to 2 than from 0·1 to 0·4 mm in size. This was due, at least in part, to microbial population density.
Manganese-resistant mutants ofAzospirillum brasilense: their response of associative nitrogen fixation, dry-matter production and nitrogen content of cheena (Panicum miliaceumL.) to different amounts of applied nitrogen in acid soil
Authors: Rai R.
Published: March 2009

Six nitrosoguanidine-induced manganese-resistant mutants ofAzospirillum brasilensewere isolated and used for associative N2fixation studies with cheena (Panicum miliaceumL.) in acid soil. Three mutants showed cross-resistance to aluminium and neomycin, but of these three only one showed cross-resistance to streptomycin. Inoculation of cheena withA. brasilenseand its mutants at different rates of applied nitrogen led to a significant increase in associative N2fixation, N content, dry-matter production and grain yield in acid soil. A saving of about 20 kg N/ha could be achieved by inoculating seeds of cheena with these mutant strains in acid soil.
Effects of nitrogen supply and drought on early development of winter wheat in the field in Eastern England
Authors: Thorne G. N. , Wood D. W. , Stevenson H. J.
Published: March 2009

Development was studied in winter wheat sown after rape or after oats in September 1984, 1985 and 1986, and in October 1985. N03-N residues from rape in October exceeded those from oats by 60, 50 and 40 kg N/ha respectively in the 3 years. Previous crops affected development only in the 1984–5 season. The first 12 apical primordia were initiated faster after rape; thereafter rates were similar, wheat after rape having two more primordia than wheat after oats. Final numbers of leaves and spikelets were each increased by one. The first five leaves appeared faster after rape so that from December onwards the number of emerged leaves was one more after rape than after oats. The double ridge and terminal spikelet stages occurred 8 and 4 days respectively earlier after rape than after oats. Development was unaffected by N fertilizer applied in November or at various times from February onwards, although growth and N uptake were increased. Drought during autumn 1985 delayed emergence of the September-sown wheat and slowed the rates of initiation of the first ten primordia and appearance of the first four leaves. Consequently the number of shoots per plant in December was only about three cf. six in the other 2 years.
The fate of carbon in dying tillers of winter wheat
Authors: Thorne Gillian N. , Wood D. W.
Published: March 2009

Changes in dry weight and14C contents of categories of shoots that did and did not survive to produce ears were examined in winter wheat grown in micro-plots in 1982–4. The weight of a group of tillers when dead was similar to their maximum dry weight when living. By anthesis dead shoots exceeded living ones in number but contributed less than 10% of total shoot dry weight.

14CO2was supplied, near the time that number of shoots was maximal, to tillers in axils of first (T1) and third (T3) main stem leaves; T1usually survived and T3usually died. The percentage of14C in the plant retained in T1was 78–94%. That retained in T3ranged from 9 to 81%. Little14C moved from dying shoots into the rest of the plant in two experiments. In another, perhaps 70% of the14C in living tillers was transferred as they died but this represented only a small proportion of total plant weight.14C not retained in tillers to which it had been given was found in all parts of the plant, including about 7% in grain.
Influence of dates of sowing on Brassica species under semi-arid rainfed conditions of north-west India
Authors: Saran G. , Giri G.
Published: March 2009

Field experiments conducted during the winter seasons of 1982–3 and 1983–4 in semi-arid rainfed conditions of north-west India indicated that sowing of Brassica species at the right time can considerably increase productivity. Sowing in the middle of October with daily mean temperatures around 26 °C produced 1·5 t/ha against 0·9 t/ha obtained from the crops sown 1 month later with daily mean temperatures around 20 °C. Under such conditions Brassica juncea cv. Pusa Bold (medium in stature and duration and bold seeded) gave the highest (1·66 t/ha) yield. Eruca sativa could withstand sowing at still lower temperature (19 °C). Increasing temperatures in the second fortnight of February adversely affected the productivity of a late-sown crop by reducing the reproductive phase.
Comparison of the effects of spring applications of ammonium chloride and other nitrogen fertilizers on take-all in winter wheat
Authors: Gutteridge R. J. , Bateman G. L. , Hornby D.
Published: March 2009

Field experiments made in 1984 and 1985 compared the effects of ammonium chloride with those of other nitrogen fertilizers applied to winter wheat in spring. The dressing was divided, 40 kg N/ha in March and 160 kg N/ha in April. In both years take-all in July was at levels which usually decrease yield, and take-all ratings were greatest in plots treated with ‘Nitro-Chalk’ (calcium ammonium nitrate) and least in plots treated with ammonium sulphate, but the differences were not statistically significant. Ammonium chloride and the other treatments, urea and ‘Nitro-Chalk’ with potassium chloride, had intermediate effects and the ranking of treatments according to disease was consistent in both years. In 1984 the mean yield was 8·27 t/ha, range 7·92 t/ha (with ammonium chloride) to 859 t/ha (with ‘Nitro-Chalk’) and in 1985, 821 t/ha, range 7·;42 t/ha (with ‘Nitro-Chalk’) to 8·55 t/ha (with ammonium sulphate). In both years treatments had no significant effects on yields and the relationship between yield and disease was obscured in 1985 because of highly correlated disease and block effects.

Whereas applying spring nitrogen all in the ammonium form seemed to decrease take-all slightly, the effects on yields of winter wheat were inconsistent. There is no evidence of extra benefit to be gained from applying the ammonium as ammonium chloride to crops at risk from take-all in this country, but there may be some benefit in applying KCl with ‘Nitro-Chalk’ top-dressings in the spring.
Long-term effects of improvement methods on Molinia caerulea dominant rough grazing on wet hill land. 1. Pasture production, quality and botanical composition
Authors: Davies D. A.
Published: March 2009

Fifteen treatments were applied in 1966 to Molinia caerulea dominant rough grazing on wet hill land at 305 m in mid-Wales. Improvement methods varied from controlled sheep grazing, application of lime, basic slag and nitrogen to the introduction of grasses and white clover with and without cultivations. Pasture productivity, feed quality and botanical composition were studied in the 4th, 9th, 14th and 18th harvest years. Controlled grazing increased D.M. production from 1·1 t/ha on the native vegetation to 3 t/ha in the 18th year. Application of lime, basic slag and 75 kg N/ha gave mean pasture production of 4·5 t D.M./ha which increased to 6·3 t D.M./ha on application of 290 kg N/ha per year. The quickest and greatest improvement was achieved by the introduction of grasses and clover following rotary cultivation or ploughing. At the lower N input these swards produced on average 6·3 t D.M./ha. Reseeds also showed the best response to 290 kg N with mean production on S. 23 perennial ryegrass (Lolium perenne L.) swards of 9·0 t D.M./ha. In vitro digestibility, crude protein and water-soluble carbohydrates were also highest on the reseeded swards.

Increased grazing eliminated Molinia before the 4th year and it was replaced by Nardus stricta and Festuca ovina. Subsequently, Agrostis tenuis replaced Nardus. On the swards given fertilizer the rate of botanical change was accelerated with the ingress of Poa spp., Holcus lanatus and Festuca rubra. The proportion of sown grass remained high on the seeded plots throughout the duration of the experiment but the white clover content was lower than expected and it virtually disappeared from most of the swards before the 18th year.

The results show the potential improvement possible on wet hill land. Given good fertilizer and grazing management, this improvement can be maintained for several years.
Long-term effects of improvement methods on Molinia caerulea dominant rough grazing on wet hill land. 2. Mineral composition of herbage and soil physical, chemical and biological characteristics
Authors: Davies D. A.
Published: March 2009

The effects of controlled grazing, application of N, P, K, Ca, and Mg and the introduction of grasses and white clover, with and without cultivations, on Molinia caerulea dominant rough hill grazing were studied over 19 years in mid-Wales. Nutrient concentration in, and uptake by, the herbage and changes in soil physical, chemical and biological characteristics were monitored periodically. Concentrations and uptake of N, P, K, Ca, Mg and Na were highest on the reseeded pastures. Nutrient balance sheets showed that the nutrients applied were most efficiently utilized on reseeded swards. They also highlighted the considerable losses of applied Ca and Mg that occurred.

Implications of the results are discussed in relation to both future agricultural use of such areas in the hills and the effects on the environment.
The effect of height of pasture and concentrate composition on dairy cows grazed on continuously stocked pastures
Authors: Kibon A. , Holmes W.
Published: March 2009

The effects of pasture height and of a cereal-based concentrate or a sugar-beet pulp supplement were studied with 30 spring-calving cows on continuously stocked, perennial ryegrass dominant pasture in a 3 × 3 latin-square design with periods of 4 weeks. Pastures were maintained at heights of about 5·0 cm (short) or 6·5 cm (control). On the short pasture, the two supplements had similar effects and were additive but on the control pasture, compared with sugar-beet pulp, the cereal concentrate depressed herbage intake. Average fat-corrected milk yields were 26·3 and 28·1 kg/day on short and control areas respectively. Both supplements increased milk yields by about 0·7 kg per kg OM supplied. Cows on the short pasture tended to lose weight. Supplements slightly increased live weight and sugar-beet pulp tended to increase body condition score. In observations continued after the conclusion of the main experiment the short pasture was more productive and of slightly higher nutritive value. Cows receiving the concentrate supplements increased total intake but this was reflected only in live weight. The total utilized metabolizable energy for the whole season was about 130 GJ/ha.
Carcass, soft tissue and bone composition of early and late maturing steers fed two diets in two housing types and serially slaughtered over a wide weight range
Authors: Nour A. Y. M. , Thonney M. L.
Published: March 2009

Seventy-one small-framed Angus and seventy-four Holstein steers were chosen to represent small and large mature types in a study designed to provide quantitative information on the effect of breed, diet and housing type on composition of carcasses from cattle slaughtered serially over a wide weight range. Within breed, steers were individually fedad libitumeither a maize-grain or a maize-silage diet and assigned randomly to one of two housing types. The effects of treatments on response variables with increasing carcass weight were tested by covariance analysis.

The rate of change of soft tissue chemical composition with increasing carcass weight was not influenced by diet, breed mature size or housing type except for ash which decreased at a faster rate in Angus than in Holstein steers. Percentages of water, protein and ash decreased while lipid increased with increasing carcass weight. At any carcass weight, Angus had more lipid and less water in soft tissue. Percentages of soft tissue protein and ash were affected by diet within breed. The energy content of soft tissue increased with weight and was affected only by breed. Angus soft tissue had more energy than that of Holsteins. Similar results were obtained when the entire carcass was analysed.

Cattle fed grain had slightly more water and less ash in bone than cattle fed silage. Angus steers had more protein and ash in bone than Holsteins. Although there was a diet × breed × housing type interaction for lipid content of bone, Holstein bone had higher lipid content than Angus bone for either diet or type of housing. All percentages of chemical components in bone, except water, increased with increasing carcass weight.

The experiment showed that large mature-size breeds have the ability to transform a high-energy diet into protein for human consumption. The percentage changes in ash, protein and lipid with increasing carcass weight appeared to follow a pattern of development similar to bone, muscle and fat, respectively, suggesting that Hammond's theory of differential growth holds also for chemical components of bovine carcasses. Bone chemical components, however, had a slightly different developmental pattern. The quantitative information on bone presented herein could be used to exploit bone as a source of human food, dietary supplements and products for bone remodelling surgery.
Effects of sex, age and body weight on selected organs of indigenous Nigerian pigs: liver, kidney, heart, lung-and-trachea
Authors: Essien A. I. , Fetuga B. L.
Published: March 2009

The absolute and relative growth of the liver, kidney, heart and lung-and-trachea were studied for 64 female, 64 castrated male and 64 intact male indigenous Nigerian pigs between birth and 672 days of age. Highly significant (P< 0·001) sex and age influences were obtained for the absolute and relative weights of the liver, kidney and heart. At 280 days of age, the four organs on average weighed 28 times their birth values; the terminal weights averaged 1·31 times their values at 280 days. Organ growth became stabilized after 280 days.

The allometric equation:Y=aXb, transformed to its linear form logY= loga+blogX, was employed to examine the relationship between organ weight and body weight. The growth coefficients 6 obtained ranged from 0·787 for kidney to 0·850 for lung-and-trachea and were similar to values reported in the literature. The accompanying highly significantR2values strongly indicate that the functions of these organs are related to overall metabolism, which in turn is strongly dependent on body size.
Effect of amount consumed and diet composition on the apparent digestibility of feed in cattle and sheep
Authors: Bines J. A. , Broster W. H. , Sutton J. D. , Broster Valerie J. , Napper D. J. , Smith T. , Siviter J. W.
Published: March 2009

Digestibility trials were conducted at two stages of lactation with each of 107 Friesian cows using three diets (60:40, 75:25, 90:10 proportions of compound feed to medium quality hay fed long). Each cow received throughout lactation fixed daily allowances of one of these diets at either 2·26 or 2·63 times average maintenance requirements (MM), or was fed ad libitum, average intake equalling 3·07 MM. The digestibilities of the diets were also measured on immature cattle at 0·76 and 1·33 MM and sheep at 0·65 and 1·27 MM.

For all classes of stock the digestibility of dry matter increased linearly and that of fibre decreased curvilinearly with increasing proportion of compound in the diet. There was no interaction of effects of diet composition and amount consumed on digestibility of feed. The digestibility of both dietary components declined for the young cattle and sheep with increased intake. The digestibilities for lactating cows were lower than for other stock but did not change with amount consumed or milk yield. Digestibility was slightly higher for first and second calf cows than for adult cows; and was higher for organic matter in mid lactation compared with early lactation for adult cows.

These results for dairy cows conflict with the generally accepted interpretation that a linear decline in digestibility occurs from once to five times maintenance intake, embracing all classes of stock.
Improvement of the water status and yield of field-grown grain sorghum (Sorghum bicolor) by inoculation withAzospirillum brasilense
Authors: Sarig S. , Blum A. , Okon Y.
Published: March 2009

The effect of inoculation withAzospirillum brasilenseon growth, water status and yield of dryland sorghum (cv. RS 610 and cv. H-226) growing on stored soil moisture was examined in three field experiments conducted during the years 1983–5.

Plants were sampled at regular intervals, and the following characteristics were measured: dry-matter accumulation, leaf area, grain yield, percentage nitrogen and phosphorus in leaves, leaf water potential, canopy temperature, transpiration, stomatal conductance and soil water depletion.

Inoculation led to an average increase of 19% in total stover dry-matter yield, as a result of higher rates of dry-matter accumulation during the early stages of growth.Azospirilluminoculation caused a 15–18% increase in grain yield in all three experiments. This increase was associated with a greater number of seeds per panicle.

The water regime of sorghum plants was improved by inoculation, as seen in their higher leaf water potential, lower canopy temperatures and greater stomatal conductance and transpiration. Total extraction of soil moisture by inoculated plants was greater (by about 15%) and occurred from deeper soil layers, compared with non-inoculated controls.

These findings indicate that inoculation withAzospirillumcan lead to yield increases in dryland grain sorghum, primarily through improved utilization of soil moisture.
Growth and dry-matter partitioning in sugar beet
Authors: Milford G. F. J. , Travis K. Z. , Pocock T. O. , Jaggard K. W. , Day W.
Published: March 2009

Data from 11 sugar-beet crops grown at different sites, in different years and with some variations in husbandry have been used to re-examine the process of dry-matter partitioning. Two-phase linear models did not describe adequately the distribution of dry matter. There was no evidence of a discontinuity in the partitioning between root and shoot at any point in crop development. It is suggested that, contrary to a recent view, events in the shoot, rather than the storage root, largely determine how dry matter is allocated between growth and sugar storage.
Effect of drought on growth and water use of sugar beet
Authors: Brown Kay F. , Messem A. B. , Dunham R. J. , Biscoe P. V.
Published: March 2009

The growth and water use of sugar beet affected by early (ED) and late (LD) drought was compared with that of irrigated (I) and unirrigated (NI) controls. Mobile shelters were used to exclude rain from ED plots during June and July, and LD plots during August and September, respectively, whereas outside these periods the ED and LD plots were irrigated as necessary.

The ED treatment affected the fibrous roots severely. Many of the roots in the top 60 cm of soil died and development of the root system below this depth was slow. Expansion of the leaf canopy slowed, radiation interception was reduced and the rate of water use fell from about 1·2 times to 0·6 times Penman potential transpiration rate. The LD treatment, which was imposed when the fibrous root system was already extensive, had little effect on the fibrous roots except in the top soil. The accessible soil water was quickly depleted and the resulting stress was accompanied by earlier senescence of leaves. The rate of converting intercepted light to crop dry matter was reduced in both treatments. However, the ED treatment was the most detrimental because the amount of light intercepted in the months of highest radiation was greatly reduced owing to the restricted leaf cover. The relative effects on growth are reflected in the final sugar yields which were 8·7, 10·5, 9·9 and 12·0 (±0·30) t/ha in the ED, LD, NI and I treatments respectively.

More of the deep soil water was used in the drought-affected plots (particularly LD) than in the irrigated controls. Maximum depths of water extraction were 140–150 cm in ED and I plots and > 170 cm in LD plots. The highest uptake rates per unit length of root (20–40 μl/cm per day) were measured in the deepest part of the root system. At all depths, uptake rates declined as the soil dried. After correcting for overestimated water use where necessary, the ratios of final dry matter and sugar yields respectively to season-long water use (June–October) were close to 1·4 and 0·8 t/ha per 25 mm for all four treatments.
Response of the components of sugar beet leaf water potential to a drying soil profile
Authors: Brown Kay F. , McGowan M. , Armstrong M. J.
Published: March 2009

For many field-grown crops, including sugar beet, there is little information on the seasonal changes in leaf water potential and its components as the soil dries. Therefore, seasonal changes in leaf water, osmotic and turgor potentials of sugar beet were measured in two seasons, in crops that experienced differing degrees of soil moisture stress. In 1983 potentials of crops exposed to early and late droughts were compared with those of irrigated crops, and in 1984 measurements were made in a non-irrigated crop. In the irrigated crop the midday leaf water potential changed little during the season, except in response to fluctuating evaporative demand. In the drought and non-irrigated treatments there was a sharp fall in leaf water potential as soon as the soil water potential decreased. The size of the midday leaf water potential was primarily determined by soil dryness. However, the leaf water potential did not decrease below about — 1·5 MPa in either year. The leaf osmotic potential declined at the same time as the leaf water potential, but the extent to which this happened differed in the two years. Only in the 1984 non-irrigated crop did the osmotic potential continue to decrease as the soil dried, suggesting that osmotic adjustment had taken place in 1984 but not in 1983. Thus higher turgor was maintained in the 1984 crop than in the 1983 drought-affected crops. Some turgors were recorded as apparently negative in 1983.

Since the leaf water potential declined to a minimum of about — 1·5 MPa, the soil water potential minima were also about — 1·5 MPa. However, deeper soil was not dried to this extent, suggesting that the extra resistance for water uptake from deep soil was limiting or the rooting density was too low.

The pattern of recovery of leaf water potential overnight suggested that the rhizosphere resistance to water movement was small, even as the soil dried. However, measurement of stem water potentials in 1984 indicated that a significant resistance to water flow existed within the aerial part of sugar beet plants. This shows that the use of the water potential in leaves as an estimate of that in stems or roots can be misleading.
Use of a simple model to study factors affecting the size distribution of tubers in potato crops
Authors: Travis K. Z.
Published: March 2009

A simple mathematical model of the distribution of potato tuber yield between size grades is presented. It has two parameters, μ, a measure of crop tuber size and σ, a measure of the spread of yield across size grades. The model is shown to be useful for the analysis of field experiments, the prediction and physiological study of tuber size distribution, and the economic analysis of management decisions. The model is applied to a variety of dataandthe practical control of tuber size discussed.
The influence of plant raising conditions and transplant age on the growth and development of crisp lettuce
Authors: Wurr D. C. E. , Fellows Jane R. , Pittam Angela J.
Published: March 2009

The influences of the temperature during plant raising and the age of plants at transplanting on the time of hearting and head weight at maturity of the crisp lettuce variety Saladin R100 were determined in seven experiments between 1984 and 1986.

Plants raised at ambient temperatures and transplanted before the end of May produced heads which were heavier and matured later than those from plants raised at higher temperatures under glass. The influence of transplant age on head weight was much smaller than that of raising conditions and there were inconsistent effects on the time of crop maturity. When the head weights at maturity of all treatments were considered there were highly significant positive correlations with total solar radiation in the periods 7 and 10 days before 50% hearting occurred. Further examination of this effect revealed that heads heavier than 800 g were strongly associated with mean daily solar radiation exceeding 15MJ/m2 in the periods 7 and 14 days before 50% hearting. This suggests that breeding for stability of head weight from crop to crop is likely to be aided by selection for consistency of head weight under a range of light levels in the prehearting phase.

The coefficient of variation of the period from transplanting to maturity, measured in terms of various environmental characters, was lowest using effective day-degrees, which take account of different levels of solar radiation at the same mean temperature. This suggests that effective day-degrees may be the best indicator of the duration of crop growth and therefore of benefit in developing techniques to predict the time of crop maturity.
Effect on yield and juice quality of sugarcane following rice
Authors: Yadav D. V. , Singh R. D.
Published: March 2009

Sugarcane is usually grown after paddy in tropical and subtropical India; this rotation is adopted when sugarcane is planted in October (autumn planting). Soil puddling is required for paddy, but puddling disturbs the soil structure and impedes development of roots beyond the puddled layer. Adverse effects on growth and yield of sugarcane are therefore expected, but contrary to such expectations, sustained or increased yields of cane after paddy have been observed (Alvarez & Snyder, 1984; Anon. 1984; Snyder el al. 1986). It appears that certain other soil factors overcome the harmful effects of adverse soil physical conditions. Therefore, the present study was undertaken to investigate such factors.
Effect of cattle slurry fractions on nitrogen mineralization in soil
Authors: Diaz-Fierros F. , Villar M. Carmen , Gil F. , Carballas M. , Leiros M. Carmen , Carballas Tarsy , Cabaneiro Ana
Published: March 2009

The mineralization kinetics of nitrogen in acid soils, and their modification by the addition of an organic fertilizer (cattle slurry), were studied by incubating a humic cambisol for 36 weeks using a method based on that of Keeney & Bremner (1967). The cumulative curve of the quantity of nitrogen mineralized in soil not given fertilizer departs significantly from Stanford's theoretical model, which predicts linear dependence of nitrogen mineralized upon √t. The observed kinetics are interpreted as due to the superposition of two mineralization processes involving different substrates.

The cumulative mineralized nitrogen curves for soil samples enriched with the various slurry fractions likewise reflect complex kinetics involving at least two main substrates. Consideration of the net mineralized nitrogen shows that F,, the solid fraction with the highest C/N ratio, clearly induced immobilization of nitrogen during the first 130 days of incubation, and analysis of the NO3/NH4 ratio suggests that this immobilization was probably at the expense of nitrate. F3, the liquid fraction, first induced a brief period of mineralization and then stabilized nitrogen levels, giving rise to a reduction in net mineralized nitrogen. The addition to the soil of F2, the semi-liquid fraction, produced results intermediate between those of the other two fractions.

In conclusion, the increase in organic nitrogen in the soil after addition of cattle slurry depends in the short term on the liquid and semi-liquid fractions, whereas long-term effects involve both the stable residues of these fractions and the more solid fraction. The labile fraction of the pool of mineralizable N benefits more than the recalcitrant fraction, and the time constants of the mineralization process are reduced.
Effect of different green manures on responses of potatoes to K and its availability in the soil
Authors: Sharma R. C. , Govindakrishnan P. M. , Singh R. P.
Published: March 2009

In a field experiment conducted from 1981 to 1984 on alluvial soil (Ustochrept) of Jalandhar, green manure (GM) of dhaincha, sannhemp, pearl millet and moong did not affect tuber yield in the 1st year but increased it in the 2nd and 3rd years. GM of dhaincha and sannhemp were more effective than the moong in reducing responses of potatoes to K. GM of pearl millet was as effective as the dhaincha or sannhemp in 1981–2 and 1982–3 when buried 55 days after sowing but was inferior in 1983–4 when buried 85 days after sowing and resulted in reduced concentrations of N and P in potato plants. GM of dhaincha, sannhemp and pearl millet increased concentration of K in potato plants and available K in soil. GM of dhaincha and sannhemp, in particular, increased soil available K by decreasing non-exchangeable K whereas GM of pearl millet increased soil available K without affecting non-exchangeable K.
Salt tolerance of five muskmelon cutivars
Authors: Mangal J. L. , Hooda P. S. , Lal S.
Published: March 2009

The salt tolerance of five muskmelon (Cucumis meloL.) cultivars Hara Madhu, Punjab Sunhari, Punjab Hybrid, Pusa Madhuras and Durgapur Madhu was assessed in field plots artificially salinized with NaCl and CaCl2. Percentage germination and melon yield of all the cultivars decreased linearly with increasing soil salinity. Decline in percentage germination with increasing salinity differed with cultivar. If soil salinity exceeded 1·11 dS/m, mean germination of muskmelon decreased at a rate of 9% per unit increase in soil salinity. Similarly melon yield decreased at a rate of 8·73% for each unit of EC exceeding 103 dS/m. Hara Madhu had the highest rate of yield drop per unit salinity increase. The salt tolerance limit of muskmelon was found to be associated with soil ECe value of about 5·20–6·32 dS/m.
Burning and cutting management and the formation of seed yield in Brachiaria decumbens
Authors: Stür W. W. , Humphreys L. R.
Published: March 2009

A central issue in the husbandry of seed crops of perennial tropical grasses is the disposal of residues from previous crops. Flowering of these grasses is usually poorly synchronized, and the sudden removal of all shoot material by burning, mechanical removal or stock concentration is necessary to create a population of tillers of similar age (Humphreys & Riveros, 1986). There has been little critical study of alternative systems of residue disposal and their effects on the ways in which seed yield is realized. Questions requiring attention are whether cutting differs from burning in its effects, and whether the fuel load, determined by the size of the previous crop, influences the potentially damaging effect of fire on crown buds.
Effect of Rhizobium inoculation, phosphorus and time and methods of nitrogen application on growth and yield of spring blackgram (Vigna mungo (L.) Hepper) and its residual effect on succeeding fodder sorghum (Sorghum vulgare L.)
Authors: Mahadkar U. V. , Saraf C. S.
Published: March 2009

Grain yield of blackgram or urdbean, a popular and highly proteinaceous pulse crop of India, is very low. This is possibly because of its cultivation on marginal and submarginal lands of low soil fertility where little attention is paid to adequate fertilizer, especially phosphorus and nitrogen. Although large achievements have undoubtedly been made in plant nutrition in cereals like wheat and rice, much less attention has been devoted to the development of suitable agro-techniques for production of pulses, especially blackgram. Inoculation with efficient Rhizobium strains and fertility management are important in the production technology of this crop. Though blackgram is regarded as excellent in symbiotic nitrogen fixation, many workers (Pate & Dart, 1961; Shanthakumari & Sinha, 1974) have opined that actual nitrogen fixation starts about 3 weeks after sowing and the senescence of nodules after profuse flowering. This results in nitrogen hunger at initial stages of crop growth as well as in the reproductive stage. Beneficial effects of starter nitrogen in blackgram have been reported by some workers (Singh et al. 1975). However, symbiotic nitrogen fixation may not be adequate to satisfy the N need of developing pods. Since no information is available on the effect of top dressing of nitrogen in the reproductive phase, the present investigations were planned to study the effect of Rhizobium. inoculation and phosphorus as well as time and method of N application on growth and yield of blackgram and its residual effect on fodder sorghum.
Nutritive value of willow (Salix sp.) for sheep, goats and deer
Authors: McCabe Sharon M. , Barry T. N.
Published: March 2009

Voluntary intake and apparent digestibility of tree willow (Salix matsudana Χ alba) and of osier willow (Salix viminalis) were measured with male sheep and goats and voluntary intake only with male deer. Both willow species had been selected for extremely rapid growth, and were grown in coppices on high fertility soil. In a first experiment spring primary growth of both willows was fed to sheep, goats and deer in early summer, whilst in a second experiment summer regrowth (i.e. secondary growth) of osier willow was fed to sheep and goats in autumn.

Although the ratio of readily fermentable to structural carbohydrate (0·51–0·70) and total N concentration (18–24 g/kg D.M.) in primary growth of the willows was less than normally found in high quality fresh temperate forages, the values were similar to those of many dried forages normally used as supplements. Averaged over sheep and goats, voluntary intake of digestible D.M. was 22% less for osier than for tree willow, this being associated with higher concentrations of lignin (197 ν 182 g/kg D.M.) and of condensed tannin (66 ν 29 g/kg D.M.) in the osier willow. The lower digestible dry-matter intake was attributable to both lower voluntary intakes and lower digestibility of the D.M. (0·57 ν 0·64). Both voluntary intake and apparent digestibility of secondary growth willow were lower than that of primary growth.

When expressed as functions of the amount required for maintenance, voluntary metabolizable energy intake of goats was approximately double that of sheep, both for primary growth (2·2 ν 1·1) and for secondary growth (1·8 ν. 0·7) willow. This was attributable to consistently higher voluntary D.M. intakes/kg W0'6 by goats, and to a trend for higher digestibility than sheep, which attained significance in Expt 2but not in Expt 1. The ratios of dry-matter intake/kg W075 per day for sheep: deer: goats fed primary growth willow were 1·0:1·5:1·9, with deer thus being intermediate between the other two species. There were no differences in voluntary intake (g/kg W0·75 per day) of sheep, goats and deer fed a high quality lucerne hay.

It was concluded that willows grown during spring and summer could adequately be used as supplementary feed during summer droughts and that willow could be used most effectively if fed to goats, followed by deer, with sheep being the least efficient. Tree willow is a preferred choice to the osier willow used here, and it was further concluded that like Lotus pedunculatus, high concentrations of lignin and condensed tannin, both of which are produced by the same biochemical pathway, are likely to be limiting nutritive value of the more leafy osier willow.
An algorithm to generate designs for variety trials
Authors: Paterson L. J. , Wild P. , Williams E. R.
Published: March 2009

We describe a computer algorithm to generate efficient incomplete-block designs for any number of varieties, any number of replicates, and any number of plots per block. It considerably extends an earlier catalogue published in this Journal by Patterson, Williams & Hunter (1978). We describe also some uses of the algorithm for which no efficient designs are available from existing sources.
A mechanism of phosphate adsorption on Narrabri medium clay loam soil
Authors: Hundal H. S.
Published: March 2009

Phosphate adsorption on Narrabri medium clay loam soil followed a four-region Langmuir isotherm equation, i.e. the plot showed four distinct linear portions. These four regions corresponded closely to saturation with respect to hydroxyapatite, β-tricalcium phosphate, octacalcium phosphate and dicalcium phosphate dihydrate, shown by a calcium phosphate solubility diagram. The differential isosteric heat of adsorption, AH, of P adsorption on soil between 4 and 22 °C, plotted against phosphate sorbed, revealed discontinuities corresponding to the breaks in slope found on the Langmuir plot.
A field method for evaluating frost injury to lucerne
Authors: Stout D. G. , Hall J. , Brooke Barbara , Moore T.
Published: March 2009

Following a winter with low temperatures during a period with no snow cover, lucerne (alfalfa;Medicago sativaL.) plants were dug from the field and various root and crown lesions were identified and rated according to severity. The plants were then put into pots of soil and grown for 6 weeks to determine if they would live or die. The relationship between lesions present at the time of digging and survival was then studied to see if the lesions could be used to predict survival. Injuries to several characteristics were found to be associated with plant death: bud vigour, leaf vigour, resistance of root bark to peeling, resistance of root to squeezing, root interior colour and, depending on site, the presence of fungi on the root surface. A model combining injury ratings for three characteristics (bud vigour, root colour, and root resistance to peeling) was developed and survival probabilities based on this model are presented. Use of this model will allow for an early evaluation of low-temperature injury without having to wait for aerial growth to occur.
Usefulness of organic manures and their nitrogen fertilizer equivalents
Authors: Sharma R. C. , Sharma H. C.
Published: March 2009

Organic manures, despite their low nutrient analysis, play a significant role in meeting fertilizer needs of crops. When manures are applied in conjunction with fertilizers, yields are generally higher than with equivalent fertilizers alone. An increase in the yield optima leads to uncertainties in working out fertilizer economy in quantitative terms. In order to overcome this, a concept of fixed yield is described in this paper.