bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Spacing on Cassava (Manihot Esculenta)
Authors: Cock James H. , Wholey Douglas , Casas Oscar Gutierrez de las 
Published: October 2008

SUMMARYThree varieties in one cassava trial and five in another were planted in a systematic density experiment which showed that optimum plant density for root yield changes with plant age. Some varieties showed a pronounced optimum plant population, whilst others showed a flattopped response curve. Reduction in yield above the optimum is due to a reduced harvest index. Yields of over 50 t–ha were obtained with varieties that respond to close spacing.
Long-term Productivity of Intensive Rice Cropping Systems on the Central Plain of Thailand
Authors: Walcott J. J. , Chauviroj M. , Chinchest A. , Choticheuy P. , Ferraris R. , Norman B. W. 
Published: October 2008

SUMMARYThe productivity of seven multiple rice-cropping systems, utilizing a short-duration cultivar under irrigation, were assessed over 5 years. Systems of one, two and three crops a year were compared. Multiple cropping reduced grain yield, panicles m-2, total dry matter and nitrogen uptake per crop. However, the unfertilized three-crop-per-year system averaged 9·1 t grain, 17·1 t DM and 126 kg N ha-1 per annum, without showing a long term decline in productivity. Recovery and utilization of nitrogen fertilizer were generally low compared to other experiments, and were highest for the early dry season cropping period.
Responses of Seedling Tea Bushes and their Clones to Water Stress
Authors: Carr M. K. V. 
Published: October 2008

SUMMARYDuring a period of dry weather, seedling tea bushes were generally less stressed than the clones which had been derived from those plants by vegetative propagation. There were interesting differences between the clones in their responses to dry conditions, but these could not have been predicted from similar observations made on the heterogeneous seedlings. However, it should be possible to use tests, based on measurements of the xylem water potential and stomatal resistance, to identify potentially drought-resistant clones at a later stage in the selection programme.
Effects of Plant Density and Thinning on High-Yielding Dry Beans (Phaseolus vulgaris) in Mexíco
Authors: Immer Aguilar M. , Fischer R. A. , S. Joshue Kohashi 
Published: October 2008

SUMMARYThe influence of leaf area and inter-plant competition on the growth and yield of a crop of high-yielding dry beans (Phaseolus vulgaris L.) in central Mexico was studied, using density and thinning treatments. The highest seed yield (4210 kg/ha at 14% moisture) was obtained with the highest density (28·8 plants/m2). Thinning showed that pods/plant was sensitive to inter-plant competition between 36 and 78 days after seeding (first flower at 50 days), but seeds/pod, and especially seed weight, were not sensitive. It is suggested that the close positive relation between yield and leaf area duration derives from the influence of photosynthate supply upon pod number.
Effects of Method and Time of Application on Uptake of Fertilizer P by Wheat
Authors: Hamid A. , Sarwar G. 
Published: October 2008

SUMMARYThe efficiency of fertilizer P uptake by irrigated wheat, as affected by method and time of application, was studied in the field by using P32 labelled superphosphate. Fertilizer P was applied at planting in a sideband, with the seed, or broadcast, and broadcast at tillering. Phosphorus applied at tillering was most productive for grain and straw yield, and its utilization was significantly higher than from P applied at planting. Phosphorus broadcast at planting was least efficiently utilized. A high correlation was found between the ratio of fertilizer P to soil P in grain and straw, and with their respective yields.
Irrigation of Dwarf Wheats in the Yaqui Valley of Mexico
Authors: Fischer R. A. , Lindt J. H. , Glave A. 
Published: October 2008

SUMMARYThe response of the latest wheat cultivars to irrigation regimes was studied between 1970 and 1975 in a heavy soil of the Yaqui Valley of north-west Mexico. Yield showed greatest sensitivity to water shortage in the period 65–110 days after seeding (spike emergence around 90 days), due largely to responses in grains/m2. More frequent irrigation increased yields 5–10% over the average of 7 t/ha obtained with the commonly-adopted five irrigation regime. Various irrigation criteria were tested: potential evapotranspiration calculations seemed the most useful. Measurement of leaf permeability (with an air flow porometer) showed more promise than the use of plant water potential (measured with a pressure chamber).
Sowing Dates of Wheat in Northern Sudan
Authors: Galil A. , Ahmed A. Gabar 
Published: October 2008

SUMMARYThe effect of sowing time and variety were tested for three consecutive years under irrigated conditions. The relation between yield and planting time was quadratic, best described by y=a+bx-ex2 where y is grain yield and x is planting time. The results showed that, irrespective of variety, the optimum sowing date is around mid-November. Varietal differences are related to number of ears per unit area, with a stronger association of yield with grain weight than with any other yield components.
Reassessment of Maximum Growth Rates for C3 and C4 Crops
Authors: Monteith J. L. 
Published: October 2008

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.
A Simple Temperature-controlled Glasshouse for Field Experimentation in the Tropics
Authors: Squire G. R. 
Published: October 2008

SUMMARYA glasshouse was built over an established tea crop in Malawi, and the internal air temperature was controlled by manual regulation of the heating, cooling and ventilation rates of two domestic air conditioners. When the inside environment was carefully matched to conditions outside, the glasshouse had only a minor influence on the tissue temperature, stomatal behaviour, leaf water potential and shoot growth of the bushes. The system could be a useful aid to experimentation on the temperature and water relations of field crops in the tropics.
Effects of N, P And K on Yield of Onion in the Sudan Gezira
Authors: Hassan Mahmoud S. , Ayoub A. T. 
Published: October 2008

SUMMARYIn NPK experiments over three seasons additional N gave highly significant increases in total yield, average bulb size and doubles, and decreased bolting. P application gave similar results but responses to K were negligible. The increases in onion yield due to N and P fertilization were accompanied by significant increases in the N and P contents of the leaves.
P and K Nutrition of Rice (Oryza sativa) in the Sudan Kenana
Authors: Ageeb Osman A. A. , Yousif Yousif H. 
Published: October 2008

SUMMARYField and plant tissue tests under Sudan Kenana conditions revealed that rice does not respond to K but response to P was very clear, both from visual symptoms, tissue analyses and in yields. As early as the seedling stage, a concentration of leaf blade-P of about 1300 ppm is considered optimum. Yield, and level of soil application, corresponding to this value were 5000 kg/ha paddy rice and 42·8 kg/ha P2O5 respectively. A low yield (2400 kg/ha) was obtained from plants receiving no P2O5. Phosphate application reduced the grain protein.
Use of a Systematic Spacing Design as an Aid to the Study of Inter-cropping: Some General Considerations
Authors: Huxley P. A. , Maingu Z. 
Published: October 2008

SUMMARYAssessment of the relative advantages or otherwise of inter-cropping compared with sole cropping needs to be done over a wide range of plant populations. Systematic spacing designs lend themselves to this, and the paper discusses the interpretation of the yield/plant population curves which can be so derived.
The Pull and Lift Required to Remove Cotton Stalks in the Sudan
Authors: Demian T. F. 
Published: October 2008

SUMMARYClearing cotton stalks after picking is enforced by law in the Sudan to stop the spread of black-arm and leaf curl diseases. The magnitude of pull and lift requirements to uproot a single plant are important parameters in designing an efficient stalk-pulling machine. With the help of a specially built apparatus, 186 plants selected at random were uprooted and measurements of the magnitude of pull and plant lift were recorded. A magnitude of 121 kg pull, accompanied by a short lift of 4·9 cm, were found necessary to loosen all plants completely. Investigations have also included the percentage of plants pulled and their root dimensions in relation to the yield point.
Effects of Some Herbicides on Cotton Weeds in the Sudan Gezira
Authors: Hamdoun A. M. , Babiker A. G. T. 
Published: October 2008

SUMMARYPre-emergence application of the herbicides fluometuron, oxadiazon, oxadiazon + diuron and norflurazon gave satisfactory weed control, particularly during the early stages of cotton growth, but supplementary hand-weeding 6 weeks after sowing was necessary for control of resistant weed species. The number of man-hours required for supplementary weeding was considerably less than on the untreated control (6–52%). The economic implications of supportive hand-weeding is briefly discussed. No herbicides had any adverse effect on cotton except fluometuron at 0.95 kg/ha and norflurazon at 1.59 kg/ha.
Effects of Periodic Removal of Mother Tubers on Yield of Dioscorea rotundata
Authors: Nwoke F. I. O. , Okonkwo S. N. C. 
Published: October 2008

SUMMARYIrrespective of the size of seed yam used, removal of mother tubers (‘milking’) from yam stands after 4 weeks of growth drastically reduced final yield, but removal after 7 weeks or more did not affect yields of individual plants of Dioscorea rotundata. If yam stands are milked after 4 weeks and the milked tuber replanted, the cumulative yield from both milked and replanted stands was significantly lower than from the control plants. However, milking and replanting mother tubers after 7 weeks or more gave cumulative yields which did not differ from the control.
Influence of BOH (Beta-hydroxyethylhydrazine) on Pineapple cv Mauritius Grown in Malaysian Peat
Authors: Chew W. Y. , Malek M. A. Abdul 
Published: October 2008

SUMMARYA field experiment studied the effects of BOH as a floral inductant on pineapple cv Mauritius grown on Malaysian peat. Spray concentrations of 0·1, 0·2 and 0·3% greatly increased fruit set and yield but reduced average fruit size, with no advantage from concentrations higher than 0·1%. Spraying the ratoon crops at different times (6, 8 and 10 months) did not affect percentage fruit set but optimum fruit yield and big fruit were only obtained at 8 months or more after planting.
Water Vapour and Carbon Dioxide Diffusion Resistances of FourHevea brasiliensisClonal Seedlings
Authors: Samsuddin Zahar , Impens Ivan 
Published: October 2008

SUMMARYDifferences in the net photosynthetic rates of two classes of Hevea clonal seedlings are explained in terms of resistances to carbon dioxide diffusion from the outside air into the carboxylation sites. The residual resistance, the sum of the mesophyll and the carboxylation resistances, is apparently related to photosynthetic rates.
Phenotypic Variation in Local Sorghums in the Sudan Nuba Mountains
Authors: Yassin T. E. 
Published: October 2008

SUMMARYTwo different collections of local sorghum strains, grown in 1975/76 and 1976/77, showed considerable and useful variation in plant height at maturity, head type and exsertion, grain colour, and days to flowering and maturity. A close and positive correlation was found between days to flowering and to maturity, and x2 tests also showed close associations among other characters. Implications of these variabilities for sorghum improvement are briefly discussed.
Neighbour Effects Between Maize and Cowpea at Various Levels of N and P
Authors: Remison S. U. 
Published: October 2008

SUMMARYMaize and cowpea were grown in mixed and pure stands, using the same overall density in all plots. Four fertilizer treatments N0P0, N1P0, N0P1and N1P1were imposed in experiments carried out during the early growing seasons of 1976 and 1977 at Ibadan in the rainforest zone of Nigeria. There was no competition between the crops for nitrogen or phosphorus and yields in mixtures were significantly higher than the means of the species monocultures, as shown by relative yield total (RYT) and C (complementation) values.
Effects of Fertilizers on the Composition and Emergence of Sunflower Seeds
Authors: Srivastava Ashwani K. 
Published: October 2008

SUMMARYCombined effects of nitrogen at 25 and 50 kg/ha as calcium ammonium nitrate and phosphorus at 30, 60 and 90 kg/ha as triple superphosphate were studied on the composition, germination and emergence of sunflower seeds. Maximum protein (26·2%) and lipid (45·8%) with the maximum emergence (85·0%) was obtained from seeds produced by crops raised in soil with 50 kg/ha of nitrogen and 60 kg/ha of phosphorus. Lowest protein (21·6%), lipid (40·8%) and 45·0% emergence were obtained from seeds of crops raised on soil with the basal level of nitrogen and phosphorus.
Effects of Fuels and Varieties on Aroma of Malawi Dark-fired Tobacco
Authors: Tanton T. W. 
Published: October 2008

SUMMARYDark-firc-cured tobacco varieties produced acceptable tobacco when cured with the wood of the fast-growing tropical tree Gmelina arborea, with an aroma as good as from the best traditional curing timber in Malawi. The addition to the fire of slow-burning, wet banana stalks or Kingelia pinnata fruit to increase the smoke did not change the desirability of the aroma. Factors which increase the stickiness of the leaf increase the desirability of the aroma of cured leaf.
Yields of Sub-humid Rainfed Crops in Relation to Soil Water Retention and Cropping Sequence
Authors: Verma H. N. , Prihar S. S. , Singh Ranjodh , Singh Nathu 
Published: October 2008

SUMMARYField experiments were conducted for 4 years to study the yield of ‘kharif’ and ‘rabi’ crops grown in sequence on two soils differing in water-holding capacity. The results indicated that drought caused greater reduction in yield of rainy-season crops on loamy sand than on sandy loam soil. In low retentivity soil it was more profitable to raise a single crop of wheat on soil-stored water. In sandy loam soil of higher retentivity, two crops a year gave much higher yields than a single crop. Of the sequences tried, maize followed by wheat gave the highest and most stable yields. For ‘rabi’ crops, stored water showed a better yield response than an equivalent amount of rain during the growing season.
Planting Density for Grain Maize in South-east England
Authors: Milbourn G. M. , Tiley G. E. D. , Carr M. K. V. 
Published: October 2008

SUMMARYGrain maize in south-east England showed a markedly flat-topped curvilinear response between density and grain yield, maximum yields being obtained over a range of 80,000–120,000 plants/ha, but yields were reduced at less than 70,000 plants/ha. A general density recommendation of 80,000–90,000 plants/ha is suggested, or a seed rate of 95,000 seeds/ha to allow for germination losses. Yields of cv Anjou 210 and DeKalb 202 showed some decline when the density exceeded 100,000 plants/ha, whereas yields of Pioneer 131 increased above this value and 100,000 plants/ha can hence be recommended. Although planting above the optimum density markedly increased the incidence of stem lodging at harvest, only a minor delay in stage of maturity occurred.
Use of a Durometer to Assess Onion Bulb Hardness
Authors: Fennell J. F. M. 
Published: October 2008

SUMMARYThe use of a durometer to assess hardness of onion bulbs is described, and compared with the use of a tensile testing machine. Results from the two tests were closely correlated, and significant varietal differences were detected in bulb hardness by both machines. The durometer is of particular value because of the simplicity and non-destructive nature of the test procedure.
Effects of Soil Properties on Sugarcane Yield in Sudan
Authors: Ibrahim Hassan Suliman 
Published: October 2008

SUMMARYSoil samples from Guneid Sugarcane Scheme, representing high- and poor-yielding sites, were collected and analysed. Yields of sugarcane were significantly and positively correlated with exchangeable potassium and clay content (P = 0·01), whereas there was a negative correlation between yield and exchangeable sodium percentage (P = 0·05). Multiple regression on soil clay content, exchangeable potassium and ESP accounted for 48·1% of the observed variability of yield of sugarcane, indicating that the clay content was the most important soil factor determining yield of sugarcane in this area.
Mixed Cropping in Northern Nigeria I. Cereals and Groundnuts
Authors: Baker E. F. I. 
Published: October 2008

SUMMARYExperiments with farmers' traditional practice of growing cereals with groundnuts demonstrated that the system consistently produced greater cash returns than sole-crop groundnuts. Increasing the proportion of cereal, and incorporating maize in addition to sorghum and millet, increased cash returns even further.
Effects of Environment on Nitrate Reductase Assays in Field-grown Cotton Leaves
Authors: Bate G. C. , Meakin M. E. R. , Oosterhuis D. M. 
Published: October 2008

SUMMARYOptimum conditions are described for the in vivo measurement of nitrate reductase activity in field-grown cotton leaves. The incubation period depended on light conditions prior to sampling. Addition of 1 mM glycolate had the effect of increasing apparent nitrate reductase activity on most days tested, and followed the general rhythmical pattern exhibited by the enzyme assayed without glycolate. While the in vivo assay appears to correlate well with soil nitrate levels, the choice of assay conditions does not appear to be absolutely critical.
Effects of Population, N and Age on Sunflower Grown for Silage
Authors: van Arkel H. 
Published: October 2008

SUMMARYIn trials with Helianthus annuus in the highlands of Kenya it appeared that the major constraints for successful utilization of sunflower for forage were: high lodging susceptibility; low DM percentage of the forage; low D-value of the forage when high yielding ( = tall) cultivars are used; and poor silage making characteristics. The proportion and quality of the stem largely governed the nutritive value of the whole plant. A reduced proportion of stem would improve all four constraints, but DM yield would also be reduced. Protein yields were highest at the beginning of flowering, but DOM yields were highest about 9 days later, towards the end of flowering. DM yields were highest towards physiological maturity of the seeds.
Uptake and Distribution of Nutrients by Yams (Dioscorea spp.) in Western Nigeria
Authors: Obigbesan G. O. , Agboola A. A. 
Published: October 2008

SUMMARYThe nutrient composition of leaves and petioles of three yam species were studied at fortnightly intervals, and in the tubers when harvested at maturity. Highest concentrations of plant nutrients were recorded in D. alata, while D. cayenensis had the lowest. The lamina was more appropriate for determination of N and P contents, while the petiole was more satisfactory for K. Peak nutrient concentration occurred between late June and early July, suggesting that that was the period of maximum demand for nutrients. The dependence of yields on nutrients was demonstrated.
Screening Cassava for Low Cyanide Using an Enzymatic Assay
Authors: Cooke R. D. , Howland A. K. , Hahn S. K. 
Published: October 2008

SUMMARYThe cyanide contents were determined quantitatively of the peeled roots of 108 cassava clones, which had been previously selected as low-cyanide by the picrate leaf-test, and compared with the qualitative picrate leaf-test scores used for rapid screening. The correlation coefficient between root tuber cyanide content (dry weight basis) and leaf-test score was r = 0·36 (P < 0·01). The picrate leaf-test, while useful for screening large numbers of clones in early stages of breeding, needs augmenting by more accurate methods. There was no significant correlation between root cyanide content and dry root yield (r = 0·18). The cyanide content varied considerably between roots of the same plant; and plants of the same cultivar grown under the same conditions. Possible improvements in the effectiveness of the cyanide screening procedure are discussed.
Leaf Water Potentials and Light Transmission of Intercropped Sorghum and Soyabeans
Authors: Wahua T. A. T. , Miller D. A. 
Published: October 2008

SUMMARYIn a field experiment to estimate water needs of intercropped sorghum and soyabeans, leaf water potential (LWP) and canopy light transmission were measured. Sorghum had 8–11% lower LWP when grown in mixture than alone, but soyabeans, shaded by sorghum had a higher LWP than in monoculture. Absolute LWP values suggest that only about 10% additional water would be required by the mixture compared with individual requirements of the aggressor species in a two-species mixture of this nature.
Response of Rainfed Pop Corn (Zea Mays Everta) to Nitrogen and Plant Population
Authors: Singh C. M. , Sood B. R. , Modgal S. C. 
Published: October 2008

SUMMARYA field experiment to study the response of pop corn (Zea mays Everta) to various levels of nitrogen and plant population was undertaken at the Research Station, Bajaura (HP) during kharif 1974 and 1975. Increases in nitrogen level from 0 to 60 kg N/ha increased grain yield significantly by 54·8%, but yield differences between 60 and 90 kg N/ha were non-significant. Various plant densities did not affect yield significantly. Yield-contributory characters were significantly influenced by treatments and were interrelated with yield under the influence of nitrogen and plant population levels.
Growth Phases in Plants and their Bearing on Agronomy
Authors: Padwick G. Watts 
Published: October 2008

SUMMARYFuture research in agronomy will doubtless lay stress on the efficient use of inputs by applying them during the most appropriate development phases of the plant, and by modifying those phases, which in some cases can now be well defined. The plant can often be influenced or stimulated well before the effect commences, storing the stimulus for the future, and the terms ‘Receptive Phase’ and ‘Responsive Phase’ are proposed to describe these stages. To apply research most effectively, receptive phases should be delimited and linked with responsive phases in a way convenient for the agronomist. Schematic diagrams can be prepared relating growth phases to field appearance, as is illustrated by examples based on cotton, rice, maize and apple.
Effects of Pelleting Cowpea and Soyabean Seed with Fertilizer Dusts
Authors: Rhodes E. R. , Nangju D. 
Published: October 2008

SUMMARYTwo field experiments were conducted to evaluate the effectiveness of several pelleting materials in increasing the yields of cowpea (Vigna unguiculata (L.) Walp.) and soyabean (Glycine max (L.) Merr.) on acid soils in Sierra Leone. The results demonstrated the beneficial effect of molybdenum, applied either alone or in combination with rock phosphate, in improving growth and yield of cowpea. The beneficial effect of molybdenum was comparable (Exp. 1) or greater (Exp. 2) than the effect of liming with 3 t/ha basic slag. However, none of the coating materials had any effect on soyabean growth and yield, although molybdenum significantly increased nodules/plant. Calcium carbonate and basic slag pelletings were ineffective in both crops.