bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

SummaryThe 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

SummaryData 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

SummaryThe 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

SummaryFor 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

SummaryA 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

SummaryThe 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 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

SummaryThe 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

SummaryIn 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

SummaryThe 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.
Nutritive value of willow (Salix sp.) for sheep, goats and deer
Authors: McCabe Sharon M. , Barry T. N. 
Published: March 2009

SummaryVoluntary 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

SummaryWe 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

SummaryPhosphate 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

SummaryFollowing 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.
The response of field beans (Vicia fabaL.) to irrigation and sowing date. 2. Growth and development in relation to yield
Authors: Husain M. M. , Hill G. D. , Gallagher J. N. 
Published: March 2009

SummaryThe growth and yield of four crops of field bean cv. Maris Bead in response to irrigation and sowing date were analysed in relation to leaf area expansion and senescence and their absorption and utilization of photosynthetically active radiation (PAR). Total dry matter (D.M.) production and seed yield were strongly correlated with total green area duration (GAD) and post-flowering GAD respectively.Total D.M. production was also strongly related to radiation absorbed by the green surfaces of the crop although autumn sowing and drought both decreased the constant of proportionality, i.e. the growth efficiency (Eg). Autumn sowings yielded more than spring sowings because they grew for longer and received 22% more radiation. Their harvest index was also about 40% higher than in spring sowings. These more than compensated for their smallerEg. Drought decreased yield mainly by decreasing radiation received andEg. Growth duration was shorter and harvest index was smaller.The rate of phenological development was strongly dependent upon temperature and to a lesser extent on photoperiod. The average thermal duration from emergence to flowering was 790 °Cd above a base of 0 °C. The time from sowing to the end of the pod growth was well represented by a simple multiplicative model in which development rate was a linear function of temperature above a base of 0 °C and photoperiod above a base of 6 h. The average photothermal duration required for 10 crops was 980 °Cd.An attempt was also made to determine the crop physiological and environmental factors which govern the change in size of the yield components of field bean crops caused by irrigation and sowing date. The final number of pods per plant was closely correlated with the rate of supply of assimilates during pod filling. Irrigation increased assimilate flux by increasing leaf area, growth rate and total dry matter during pod growth. Both the rate and duration of pod growth were little affected by irrigation. Autumn sowings produced heavier pods and beans due to both a faster rate and a longer duration of growth which were associated with a greater production of assimilate during the seed growth period. Seed growth depends on both the current assimilate and stored reserves, the latter especially when plants were subjected to environmental stress.
Morphology of white clover (Trifolium repensL.) plants in pastures under intensive sheep grazing
Authors: Brock J. L. , Hay M. J. M. , Thomas V. J. , Sedcole J. R. 
Published: March 2009

SummaryThere has been little study on the growth and morphology of individual plants constituting the population of white clover in mixed swards under grazing. Such information is required if the mechanisms governing plant productivity and persistence are to be understood.Intact white clover plants were sampled from intensively sheep-grazed pastures under set stocking, rotational grazing, and a combination of both systems, by taking turves (250 × 250 mm), and washing out the plants, every month for a year. Characters measured for every stolon of each plant were: presence of a growing point; numbers of leaves, roots and axillary buds; stolon length. Total plant leaf and stolon dry weight were also recorded. Plants were classified according to degree of branching, and the contribution of each branching order to the population determined.There were strong seasonal variations in plant size (leaf and stolon dry weight, stolon length, and numbers of stolons and leaves per plant) which showed a significant decrease in spring with recovery over the following summer. This was paralleled by a rapid increase in the proportion of less branched plants (1st and 2nd branching order) in the population from 60 to 80% in spring, as higher-order plants broke up into smaller- and lower-ordered plants at this time. Numbers of roots per plant increased over winter to peak in early spring then declined in the following summer-autumn. While system of grazing management had no significant effect on branching structure of plants, it had a large effect on plant dry weight; rotationally grazed plants were 2·5 times larger than set stocked plants (0·182 cf. 0·073 g respectively).Other general features of plant morphology were that each successive order of branch stolons was shorter and length before branching was less than that of their preceding parent stolon. The highest branching order observed was 6th order. There was no relationship between branching and numbers of roots; in branched plants only 55% of stolons were rooted regardless of plant order, but rooted stolons accounted for 85% of total stolon length and carried 62, 48 and 90% of the leaves, growing points and axillary buds per plant, respectively.Comparison with other studies suggests that the processes outlined in this report may be common to white clover growth under grazing over a wide range of favourable environments.