bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of mulches and transpiration suppressants on yield, water use efficiency and uptake of nitrogen and phosphorus by sorghum under dryland conditions of north-western India
Authors: Raghavulu P. , Singh S. P. 
Published: March 2009

SUMMARYField experiments consisting of three mulch treatments (no mulch, straw mulch and dust mulch) and six transpiration suppressants (no suppressant, kaolin, phenyl mercuric acetate, atrazine, mobileaf or alachlor and 2-chloro ethyl trimethyl ammonium chloride) were conducted under dryland conditions during the summer rainy seasons (July–November) of 1976, 1977 and 1978. Compared with no mulch, straw mulch increased yield in all 3 years, water use efficiency in 1977 and 1978, and uptake of N and of P in 1977 and 1978. Dust mulch had only a marginal advantage. Amongst transpiration suppressants, only kaolin and atrazine had a marked effect. Both these chemicals increased grain yield, water use efficiency and uptake of N and P, compared with no suppressant.
A model to predict the effects of complex row spacings on the yields of root crops
Authors: Benjamin L. R. 
Published: March 2009

SUMMARYA mathematical plant competition model developed by Currah (1975), and subsequently modified by the author, is briefly described. The model has two useful properties: (a) it can cope with complex irregular row spacing systems such as occur in commercial practice and (b) it can be ‘calibrated’ to the yield values at any site by using data from previous crops.Parameter values of the modified model are calculated for both carrot and red beet crops. At least 70% of the variation in these data could be accounted for by fitting the model, a performance which was similar to, but never as good as, fitting analysis of ariance models. There were no systematic deviations between the fitted and observed values.Previously estimated parameter values were used to predict mean root weights of carrot and red beet storage roots. Overall agreement between predicted and observed data was good, although some systematic deviations occurred.The practical value of the modified version of the model and its strengths and weaknesses are discussed.
Yield response of sorghum cultivars to inorganic nitrogen fertilizer
Authors: Pal U. R. , Murari K. , Malik H. S. 
Published: March 2009

SummaryField experiments were conducted during the rainy seasons (June–October) of 1978 and 1979 in order to determine the effect of fertilizer N rates (0, 40, 80 and 120 kg N/ha) on yield and yield attributes of some new sorghum cultivars in northern India. Sorghum hybrid varieties yielded more than pure line varieties, hybrid CSH 5 outyielding all other cultivars including other hybrid varieties because of its greatest number of grains per panicle. Nitrogen application at 80 or 120 kg N/ha brought about significant improvement in number of grains per panicle and yield per ha.Cultivar Χ N rate interactions were significant, in affecting the yield per ha and number of grains per panicle in 1978, whereas such differential response of sorghum cultivars to N rates did not occur in 1979. Sorghum hybrid varieties, even at lower N rates, produced identical yields to the pure line varieties supplied with higher N rates.
Effects of feeding frequency and level of feed intake on chemical composition of rumen bacteria
Authors: John A. 
Published: March 2009

SummaryCell mass (dry matter per cell) and cell composition (concentrations of DNA, RNA, phospholipids, total N, a-dextran, diaminopimelic acid and 18 common amino acids) of rumen bacteria were measured at various times after feeding sheep chaffed lucerne hay (Medicago sativaL.) once daily. Cell composition was measured with sheep fed once hourly. Total DNA and RNA pool sizes in the rumen were also measured.While cell composition was not affected by level of feed intake (700 gv. 1050 g dry matter/day), total DNA, RNA and D.M. pool sizes in the rumen increased with increasing feed intake. With sheep on the once daily feeding regimen relative rumen pool sizes in rumen digesta at various times after feeding were: RNA, 4 > 14 > 0 h; DNA, 4 and 14 > 0 h; D.M. 4 > 14 > 0 h. With the hourly feeding regimen pool sizes were similar to the averaged daily values for sheep fed once daily.When sheep were fed once daily bacterial cell mass, DNA and phospholipid concentrations peaked at 12–14 h after feeding and subsequently decreased to the 0 h value. RNA concentration was maximal at about 4 h after feeding and declined to near the 0 h value at about 14 h. RNA concentrations in bacteria were highly correlated with gas production rates by whole rumen digesta. The ratio RNA:DNA was highest shortly after feeding, decreased to below the 0 h value at about 14 h and then increased to the 0 h value. The relative concentrations of a-dextran in bacteria were: 4 > 14 > 0 h. Cell composition witli sheep fed hourly tended to reflect the averaged daily values for sheep fed once daily.These results are discussed with regard to changes in estimated fermentation rate and pool size of bacteria in the rumen. It is suggested that changes in average composition (DNA, RNA, total N and RNA: DNA ratio) of mixed rumen bacteria reflect changes in the average growth rate of the population.
The relative importance of some sources of root-weight variation in a carrot crop
Authors: Benjamin L. R. 
Published: March 2009

SummaryThe relative importance of some sources of plant-to-plant root-weight variation in a field-grown carrot crop was investigated in two experiments sown in contrasting soil conditions but using the same seed lot and experimental design. In each experiment the following possible causes of root-weight variation were recorded on an individual plant basis: umbel order and size of seed, sowing depth, time taken for seedling emergence, length of cotyledons at emergence, distance to nearest neighbours within a row and row position within the seed bed. The relative importance of these differing sources of root-weight variation was assessed by determining how much of the variation in In (root dry weight) they accounted for at two harvests in each experiment.In the first experiment, carrot seeds were sown in warm, moist conditions in May. These conditions gave a near-ideal emergence, 82% of seedlings emerging over only 5 days. Thirteen days after sowing, the most important source of root-weight variation, out of the variables measured, was position of the row within the bed. However, approximately two-thirds of the root-weight variation could not be attributed to any of the measured variables.In the second experiment carrot seeds were sown in hot, drying conditions in July. The subsequent spread of seedling emergence extended over approximately 40 days. The total sum of squares of In (root dry weight) in this experiment was six times greater than the sum of squares in the first experiment. At 105 days, 61% of the rootweight variation in Expt 2 was accounted for by differences in time of seedling emergence. Differences in cotyledon length, measured when fully expanded, accounted for 24% and sowing depth differences accounted for 19% of the root-weight variation. Differences in umbel order, seed size and distance to the nearest neighbouring plants within a row never accounted for more than 8% of the sum of squares of In (root dry weight) in either experiment. Thus these variables were not important sources of rootweight variation. In contrast variables which affected the time of seedling emergence, such as sowing depth and physical conditions around the seed, were major sources of root-weight variation.
Direct drilling and shallow cultivation compared with ploughing for spring barley on a clay loam in northern England
Authors: Clutterbuck B. J. , Hodgson D. R. 
Published: March 2009

SummaryAn experiment was made on a clay loam soil to compare direct drilling, shallow cultivation and ploughing for spring barley over a period of 3 years (1975–7). At a uniform rate of fertilizer application (75 kg N, 40 kg P2O6, 40 K2O/ha) combined drilled with the seed, the mean grain yields over 3 years were 5·89, 6·07 and 6·13 t/ha, respectively, direct drilling producing significantly less grain than shallow cultivation or ploughing in 1975 only.For 1975 and 1976 the mean uptake of nitrogen by shoots of barley at anthesis was 25 kg N/ha less after direct drilling than after ploughing but in 1977 there was no difference. The smaller uptake of nitrogen by direct-drilled barley in 1976 was more likely caused by less available nitrogen in the soil than by smaller root systems. Soil strength (cone resistance) and soil bulk density of the direct-drilled treatments were greater than those of the ploughed and shallow cultivated. Although concentration gradients of extractable phosphorus and potassium formed in direct-drilled and shallow-cultivated soils, the quantities of these nutrients in the top soil differed little between the treatments. After 3 years there were more deep burrowing earthworms (particularly Lumbricus terrestris) in tilled than in untilled soil.
Resistance in vegetable marrow and other Cucurbita spp. to two British strains of cucumber mosaic virus
Authors: Walkey D. G. A. , Pink D. A. C. 
Published: March 2009

SummaryMost commercial cultivars of Cucurbita pepo L. reacted by producing severe leaf symptoms when infected with either of two British strains of cucumber mosaic virus. Resistance was identified in some pumpkin-types of C. pepo, with the highest level in cv. Cinderella. Studies with selfed populations produced from selected resistant plants demonstrated that resistance in cv. Cinderella is heritable.
Utilization of poor quality roughages: response of sheep fed native hay supplemented with urea by different methods
Authors: Umunna N. N. 
Published: March 2009

SUMMARYSheep were used to study the utilization of low quality native hay supplemented with urea by different methods. Urea supplement was fed either once daily or twice daily or the same quantity of urea used to spray the hay before feeding. These treatments were compared with basal and groundnut cake based supplemented controls. An attempt was made to balance both the mineral and energy intakes. The provision of extra nitrogen in the form of either urea or groundnut cake resulted in improved weight gain, feed intake and feed conversion. Feeding of urea-sprayed hay marginally improved live-weight gain, feed intake and feed conversion over the other methods of urea supplementation. Dry-matter digestibility and nitrogen retention were increased and urinary nitrogen excretion reduced by feeding the urea-sprayed hay.
A reappraisal of stem reserve contribution to grain yield in spring barley (Hordeum vulgare L.)
Authors: Daniels R. W. , Alcock M. B. , Scarisbrick D. H. 
Published: March 2009

SUMMARYPre-anthesis stem reserve contribution to grain yield was assessed in two spring barley cultivars of contrasting height. It was greatest in the taller, but final grain yields were similar. Partitioning of total reserve capacity to various plant parts showed that the leaf and sheath below the peduncle were most important, followed by stem internodes which had increasing reserve capacity up to internode 4.It is suggested that stem reserves are valuable for yields commonly achieved in U.K. commercial practice.High grain yields were associated with large positive increases in stem dry weight after anthesis. This would indicate that the source capacity to boost yield is more than proportional to that required to fill the grain alone.
The effects of white clover mosaic virus infection on the yield of red clover (Trifolium pratenseL.) in mixtures and in pure stands
Authors: Scott S. W. 
Published: March 2009

SUMMARYThe effects of white clover mosaic virus infection on the yield of two red clover varieties grown alone and in mixtures with either perennial or hybrid ryegrasses were examined. The spread of this virus within the pure clover plots was rapid. Clover drymatter yields were reduced and these losses were greater in the grass–clover mixtures than in the pure clover plots. Reductions in yield of about 70% were recorded at the first cut in mixtures of Sabtoron and Sabrina. The response of the clover to different levels of virus infection was best described by a negative linear relationship.Yields of Sabrina hybrid ryegrass increased as the levels of virus infection in the clover increased. This compensated for the losses in yield of the legume, leaving total sward yields unaffected by the virus.
A study of mole drainage with simplified cultivation for autumn-sown crops on a clay soil
Authors: Ellis F. B. , Christian D. G. , Bragg P. L. , Henderson F. K. G. , Prew R. D. , Cannell R. Q. 
Published: March 2009

SummaryGrain yield of winter barley in the year preceding the experiment (1978) was relatively uniform over the site. In 1978–9 after the drainage treatments had been introduced, growth and yield of winter wheat were not affected by drainage, probably due to a compact layer at 20 cm that prevented the mole drains from controlling the water table (Harris et al. 1984).In 1979–80 after disrupting this layer, root growth in undrained plots during the winter and spring was severely restricted by the presence of a water table 20 cm from the soil surface, although some root axes were able to grow down to 75–100 cm below the soil surface. The differences in root distribution patterns between drained and undrained plots disappeared after the water table declined in April. Uptake of nitrogen, phosphorus and potassium were less on undrained plots. Dry-matter production, leaf area index and peak number of tillers was also depressed, so that the yield of winter wheat was 0·74 t/ha greater on the drained treatment; the grain from the drained plots contained fewer impurities and weed seeds.
Calcium metabolism in dairy sheep
Authors: Economides S. 
Published: March 2009

SummaryCalcium metabolism in dairy sheep was studied using radioisotope and balance techniques. The rate of calcium absorption increased, but the efficiency of calcium absorption decreased, with increasing calcium intake in dry sheep. Endogenous faecal and urinary calcium losses, and the rate of calcium absorption, decreased, but the efficiency of calcium absorption increased in pregnant sheep given a calcium-deficient diet. The rate and the efficiency of calcium absorption and the calcium balance of lactating ewes were not influenced by the prepartum level of calcium intake, when calcium intake in early lactation was high. Endogenous faecal calcium loss was related to dry-matter intake, and total faecal calcium loss was related to calcium intake.
Breeding of improved open-pollinated populations of spring-sown onions
Authors: Dowker B. D. , Horobin J. F. , Crowther T. C. , Fennell J. F. M. 
Published: March 2009

SummaryVarious population improvement methods were applied to the spring-sown bulb onion crop. Synthetic populations were developed by recurrent selection, basing this selection on the performance of inbred lines per se for improved yield, bulb quality and storage performance. From the synthetic populations, partially inbred populations were also developed by half-sib selection methods. Results showed that gains, primarily in storage performance and marketable yield, were obtained in many of the synthetics. The mean gain in yield per cycle was of a similar magnitude to gains reported for maize using similar selection procedures although individual onion synthetic populations varied considerably in their achieved gains. Further gains in quality and storage performance, with no reduction in yield, were obtained by the development of partially inbred populations from the synthetics. These results are discussed in relation to the breeding of improved onion cultivars in the U.K.
Effect of intake and feeding frequency on feeding behaviour and quantitative aspects of digestion in sheep fed chaffed lucerne hay
Authors: Ulyatt M. J. , Waghorn G. C. , John A. , Reid C. S. W. , Monro J. 
Published: March 2009

SummaryChaffed lucerne hay of 64% apparent organic matter (OM) digestibility was fed to wether sheep under four feeding regimens: two levels of dry matter (D.M.) intake (700 (L) and 1050 (H) g/day) and within each level two feeding frequencies (once a day (daily) and once an hour (hourly)). Three separate groups of sheep were used concurrently: a slaughter group was used to obtain feeding behaviour data and to measure pool sizes and obtain samples from the reticulo-rumen; a digestion group, in which each sheep was prepared with a rumen and a duodenal cannula, was used to measure duodenal digesta flow, rumen microbial growth and reticulo-rumen motility; a balance group was used to measure digestibility and nutrient balances.High D.M. intake increased reticulo-rumen pool sizes and flow rates but it did not affect apparent digestibilities or the proportions of OM, fibre, cellulose, hemicellulose, lipid and nitrogen digested in the stomach and intestines. Increased feeding frequency had a major effect on reticulo-rumen pool sizes but did not affect apparent digestibilities or partition of digestion of non-nitrogenous constituents. Daily feeding resulted in increased total-N flow to the duodenum; however, N retention was significantly greater with frequent feeding. It is suggested that this was due to a more efficient tissue utilization of N.The kinetics of digesta flow within the reticulo-rumen, expressed as fractional flow rates, were studied with data from sheep fed hourly. The fractional inflow, outflow and disappearance rates for OM, fibre, cellulose and hemicellulose did not change with an increase in intake because of an equivalent increase in reticulo-rumen volume. Increasing D.M. intake by 50% resulted in a 24% increase in water intake, a 19% increase in reticulo-rumen water volume, and a 49% increase in water outflow rate. The data suggest that the increased outflow of water was achieved by increasing the net flow of water across the mucosa into the reticulo-rumen, rather than by increasing salivation.There was no difference between treatments in the frequency of reticulo-rumen contractions. It was calculated that for each A sequence contraction, OM flow was 0·26 and 0·37 g and water flow was 4·38 and 0·36 g on L and H intakes respectively. A 50% increase in intake resulted in a 42% increase in OM passage per A sequence contraction. This increased passage with intake was not accompanied by an increase in reticulorumen contraction frequency.
Evaluation of some chemical extractants for predicting response of wheat grown in pots to copper in Sub-Himalayan soils
Authors: Sakal R. , Singh A. P. , Singh B. P. , Sinha R. B. 
Published: March 2009

SummarySeven out of ten chemical extractants were found to be promising for the evaluation of critical limit and response of wheat grown in pots to Cu application in Sub-Himalayan hill and forest soils of recent alluvium origin. The critical limit of available Cu using DTPA-CaCl2(pH 7·3), DTPA-NH4HCO3 (pH 7·6), EDTA-(NH4)2CO3 of pH 8·6, EDTANH4OAc (pH 7·0), n-NH4OAC (pH 7·0), n-NH4OAC (pH 4·8) and n-Mg(NO3)2 of pH 5·9, was 0·66, 1·73, 1·95, 1·38, 0·13, 0·20 and 0·47 mg Cu/kg, respectively. The amount of Cu extracted by these extractants was positively and significantly correlated with ‘Bray's percent yield’. Apart from ‘Bray's per cent yield’, the Cu extracted by most of these extractants was positively and significantly correlated with Cu concentration in the third leaf of wheat, Cu uptake by wheat shoots and organic carbon content of the soils, and negatively correlated with soil pH but the value of this relationship did not approach the 5% level of significance. n-Mg(NO3)2 of pH6·7, N-NH4NO3 and 0·1 n-HCl were found to be ineffective extractants. Among chelating agents, DTPA-CaCl2 was found to be most and EDTA-NH4OAc least promising extractant. N-NH4OAC (pH 4·8) proved to be better than N-NH4OAC (pH 7·0). The critical Cu concentration in the third leaf of wheat was 8·8 mg Cu/kg, below which responses in dry weight to Cu application may be expected.
The use of two mating systems in breeding for resistance toMaruca testulalisGey. in cow peaVigna unguiculata(L.) Walp.
Authors: Woolley J. N. , Evans Alice M. 
Published: March 2009

SummaryResistance to insects in cow peas was studied in a diallel cross and in a test cross. Number of pods and seed yield under unsprayed conditions, expressed as a percentage of their values under sprayed conditions, were confirmed as reliable characters for the assessment of resistance and as suitable for diallel analysis. Non-allelic interaction was not detected for these ratios despite its presence in yields. Resistance to flower damage byMarucaand resistance to all damage by post-flowering pests were both highly heritable and were controlled polygenically by alleles showing partial dominance.The test cross was not as informative as the diallel cross in the analysis of the genetic control of resistance in a group of moderately resistant lines, but was useful in selecting the best of these for future crosses. The results from both schemes suggested that resistance should be accumulated by intercrossing resistant lines before attempting to transfer it to agronomically-preferred susceptible lines.
Movement of potassium in an Ustochrept soil profile in a long-term fertilizer experiment
Authors: Ganeshamurthy A. N. , Biswas C. R. 
Published: March 2009

SummaryDownward movement of potassium (K) was studied in the soil profiles of a longterm fertilizer experiment. The distribution of different forms of K and the percentage K saturation of the CEC of soil, at various depths of the differentially treated plots, indicated that applied K moved down to 75 cm depth in the high-K plots after nine cycles of a maize-wheat-cow peas crop rotation. However, movement of K was not noticed in plots not given K fertilizers. Plant uptake of K far exceeded the amounts of applied K. Application of K fertilizer reduced the release of K from the non-exchangeable reserves. Forms of K and the percentage K saturation of the CEC of soils were significantly correlated.
Water relations of winter wheat. 5. The root system and osmotic adjustment in relation to crop evaporation
Authors: McGowan M. , Blanch P. , Gregory P. J. , Haycock D. 
Published: March 2009

SummaryShoot and root growth and associated leaf and soil water potential relations were compared in three consecutive crops of winter wheat grown in the same field. Despite a profuse root system the crop grown in the second drought year (1976) failed to dry the soil as throughly as the crops in 1975 and 1977. Measurements of plant water potential showed that the restricted utilization of soil water reserves by this crop was associated with failure to make any significant osmotic adjustment, leading to premature loss of leaf turgor and stomatal closure. The implications of these results for models to estimate actual crop evaporation from values of potential evaporation are discussed.
Dormancy responses to post-harvest application of growth regulators in Dioscorea species. 2. Dormancy responses in ware tubers of D. alata and D. esculenta
Authors: Wickham Lynda D. , Passam H. C. , Wilson L. A. 
Published: March 2009

SummaryThe effects of post-harvest application of gibberellic acid on dormancy of tubers of Dioscorea alata and D. esculenta were examined. In both species, gibberellic acid extended the dormancy of immature and mature tubers but when GA3 application was made after storage for varying lengths of time, there was a decreasing effect with increased storage time. Dormancy was also reinduced in germinating tubers, that had gone through a normal dormant period, as a result of gibberellic acid treatment. A possible mechanism of dormancy in tropical yams is discussed. It is concluded that use of gibberellic acid as a means of extending the storage life of yam tubers by post-harvest application is a distinct possibility.