bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Dated Soil Moisture Stress on Crop Yields
Authors: Nairizi S. , Rydzewski J. R.
Published: October 2008

Crop yield response to soil moisture deficiency varies for different crops and also depends on the time of its occurrence in the growth cycle. Many attempts have been made to derive a single relationship between total water consumption and yield for various crops, but this has proved of limited use, because the effect of time was omitted from such production functions. Jensen (1968) derived two expressions, for determinate and indeterminate crops, bringing the time element into his expressions indirectly by a parameter (λi) which defines the relative sensitivity of the crop to soil moisture stress at different growing stages. The usefulness of this approach depends on the accuracy with which this parameter can be determined. The aim of this paper is to derive λi for a number of crops from available experimental data and subsequently to find a way of computing the quantitative contribution of each single irrigation application to the crop yield. This should lead to a more rational use of irrigation water resources.
Combining Ability and Rank Correlations in a Diallel Cross of Indian Mustard (Brassica juncea)
Authors: Asthana A. N. , Pandey V. K.
Published: October 2008

A diallel cross study on Indian mustard revealed a preponderance of additive gene action for seven characters out of the nine studied. Plant height and seeds per siliqua seemed to be controlled by both additive and non-additive gene action. Days to flower, number of secondary branches, length of main branch, number of siliquae on the main branch, length of siliqua and yield per plant were mainly controlled by additive gene action, whereas oil content was determined mainly by non-additive gene action. Heterosis was prevalent and the maternal effect was not generally apparent in the crosses. Rank correlations established a positive correlation between performance per se and GCA, and between heterosis and SCA.
Plant Husbandry and Management Techniques for Growing Grain Legumes Under Simulated Tropical Conditions in Controlled Environments
Authors: Summerfield R. J. , Huxley P. A. , Minchin F. R.
Published: October 2008

Practical solutions are described to problems incurred in growing cultivars of cowpea, soyabean, lima bean and pigeon pea under simulated tropical conditions in controlled environments, namely (a) ‘Saxcil’ growth cabinets in which daylength, day and night temperatures, light intensity and quality, relative humidity and CO2, concentration are precisely controlled and can be varied over time; (b) compartmentalized glasshouses and adjoining dark compartments where daylength, and day and night temperatures are automatically controlled and night-break illumination can be provided, and (c) heated plastic film houses in which daylength-insensitive tropical legumes can be grown to maturity during the UK summer months since the environment of the wet tropics can be simulated in all respects other than daylength.
Agronomy of Linseed Oil Cultivars (Linum usitatissimum) in Northern Nigeria
Authors: Yayock J. Y. , Quinn J. G.
Published: October 2008

Forty-six cultivars of linseed oil (Linum usitatissimum L.) were grown under wet and dry season conditions in the Sudan Savanna of Nigeria. Only during the dry season was production good and cv Dunes consistently outyielded all other cultivars in terms of seed and oil content. Trials of sowing dates gave maximum seed yield and oil content from plots sown during late October. In row spacing trials, rows 15–22 cm apart and seed rates of 58–78 kg/ha were found to be the most practicable. There was a linear relation between increasing rates of nitrogen and seed yield, maximum production being obtained at 55–88 kg N/ha, but oil content was slightly depressed at levels above 33 kg N/ha.
Storage of Fresh Cassava (Manihot esculenta). II. Simple Storage Techniques
Authors: Booth Robert H.
Published: October 2008

The development of two simple techniques, box storage and field clamps, which allow curing and storage of fresh cassava roots for 1 and 2 month periods, is described. Consistent and acceptable results have been obtained following storage of roots in boxes packed in moist but not wet sawdust and kept at ambient temperatures. The design of field clamps that maintain internal temperature below 40°C, to allow successful curing and storage, varies in different seasons. Storage life of roots is enhanced by the selection of roots in good condition, and any delay in placing the roots in storage results in poorer out-turns.
Nitrogen Nutrition of Cowpea (Vigna unguiculata). I. Effects of Applied Nitrogen and Symbiotic Nitrogen Fixation on Growth and Seed Yield
Authors: Summerfield R. J. , Dart P. J. , Huxley P. A. , Eaglesham A. R. J. , Minchin F. R. , Day J. M.
Published: October 2008

Effectively nodulated cowpea plants, grown in pots without applied nitrogen, were vegetatively equal to non-nodulated plants supplied with 60 ppm N throughout growth (88 days) and produced significantly greater seed yields. Supplying non-nodulated plants with 120 or 240 ppm N improved seed yields (but not significantly) compared with plants completely dependent on symbiotic fixation. Nodulation promoted branching, and improved pod set and/or retention compared with plants relying on applied N.
Effects of Monocrotophos on Insect Damage and Yield of Cowpea (Vigna unguiculata) in Southern Nigeria
Authors: Dina S. O.
Published: October 2008

The effect of one, two or three applications of monocrotophos at 1120 g ai/ha at weekly intervals was determined on cowpea var. Ife Brown. All regimes were equally effective in grain production in early 1974 but spray applications 35 and 42 days after planting gave the best result in the late crop. Grain production from two applications was not significantly different from three applications in 1975. The control plots in the late season of both years failed, due to moisture stress and lack of pest control measures. It is considered that two sprays at flowering is adequate to forestall a crop failure in this variety.
Studies in Mixed Cropping. I. Seasonal Differences in Relative Productivity of Crop Mixtures and Pure Stands in the Kenya Highlands
Authors: Fisher N. M.
Published: October 2008

An experiment is described in which the productivity of maize–bean and maize–potato mixtures in alternate rows was compared with pure stands of the component species in four cropping seasons. In seasons with low rainfall, yield from the mixtures fell short of that from pure stands, but in one exceptionally wet season a yield advantage was found for maize–bean mixtures. The poor performance of mixtures in low rainfall seasons appeared to result from large reductions in maize yield attributable to competition from the potato or bean. In the one high-rainfall season, no such reduction in maize yield occurred. An implication of these findings for farming systems with mixed cropping is discussed.
Diallel Analysis of Genetic Variation in Pigeon Pea (Cajanus cajan)
Authors: Dahiya B. S. , Brar J. S.
Published: October 2008

A diallel analysis of flowering time, pod number, 100-seed weight and yield of six cultivars ofCajanus cajan(L.) Millsp. was studied. Additive inheritance was important in determining flowering time, but the dominance component was higher than the additive component, and over-dominance was observed for pod number, 100-seed weight and yield. Heritability estimates for all the traits except flowering time were quite low, and the bulk population method of breeding was suggested for early segregating generations. The graphical analysis of the diallel cross was in close agreement with the findings from variance component analysis. It is suggested that the best cross would be that between two parents chosen on the basis of their low g.c.a. for flowering time and their high g.c.a. for other traits.
Factors in a Package of Practices for High-production Maize in Northern Nigeria
Authors: Taylor B. R.
Published: October 2008

In trials over 2 years at five locations in Northern Nigeria single inputs were removed from a package of maize practices. The improved variety was most important and increased the yield of the otherwise complete package by 86%. Early sowing and high plant population were not important in all trials. The high fertilizer treatment (125–50–50 kg NPK/ha) consistently exceeded the half rate, with a mean increase of 31%. It was suggested that, with clean weeding, priority should be given to the improved variety, high fertilizer and early sowing. High populations, involving changes to traditional techniques, may be introduced gradually.
The Sulphur Nutrition of Coconut
Authors: Silva M. A. T. De , Anthonypillai Greta M. , Mathes D. T.
Published: October 2008

The sulphur content in the sixth leaf from the apex of coconut palms was found to be the most sensitive index to sulphur treatments. Although the S concentration in this leaf correlated negatively with applied levels of S, the response curve was concave. Sulphur treatments increased the total yield of fruits and weight of copra, but decreased the weight of kernel per nut. The derived curve for yield versus S concentration in the tissue was C-shaped, attributed to growth dilution effects caused by enhanced initial growth following the restoration of a nutrient in minimum.
Some Useful Equations for Biological Studies
Authors: Landsberg J. J.
Published: October 2008

The properties are discussed of a number of relatively simple equations that describe non-linear relations of the type which frequently occur in biology. Most of the equations can be linearized by applying simple transformations (e.g. logy, log (a–y), I/y) to either y or x, or both. Some approximate methods of fitting the equations to experimental data are given, but statistical methods are not discussed in any detail.
A Single Plant Thresher for Vegetable Seeds
Authors: Smith B. M. , Lickorish G. R.
Published: October 2008

A small bench-mounted seed thresher for vegetables has been developed for the use of plant breeders. The construction and operation of the thresher is described.
Effects of Spacing on Cassava (Manihot Esculenta)
Authors: Cock James H. , Wholey Douglas , Casas Oscar Gutierrez de las
Published: October 2008

Three 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

The 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

During 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

The 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

The 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

The 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

The 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

Figures 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

A 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

In 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

Field 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

Assessment 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

Clearing 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

Pre-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

Irrespective 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

A 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

Differences 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

Two 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

Maize 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

Combined 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

Dark-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

Field 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

Grain 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

The 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

Soil 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

Experiments 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

Optimum 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

In 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

The 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

The 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

In 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

A 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

Future 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

Two 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.
Mixed Cropping in Northern Nigeria II. Cereals and Cotton
Authors: Baker E. F. I.
Published: October 2008

Cotton is widely grown as a cash crop by subsistence farmers of Northern Nigeria, although it is invariably sown too late to produce yields that would allow economic use of insecticides to control insect pests. This late sowing is because subsistence farmers always emphasize the production of food crops, delaying sowing of cotton until these are established. Experiments are described in which cotton was sown early within the cereal, without affecting cereal yields yet producing significantly greater cash returns than sole cereal.
Studies in Mixed Cropping. III. Further Results with Maize-Bean Mixtures
Authors: Fisher N. M.
Published: October 2008

In contrast to earlier results, a clear advantage from mixed cropping of maize and beans (Phaseolus vulgaris) was found in the long-rain seasons (March to September) of 1976 and 1977. Pure stand yields were low due to drought in 1976 and excessive rainfall in 1977. These and other results for long-rain seasons in Kenya suggest that mixtures are more efficient where pure stand yield levels are low, but there is little difference between cropping systems where levels are high. Light interception by maize leaves was quite small until late in the life of the bean crop.
Variability Studies and Breeding for Increased Oil Content in Rapeseed and Mustard
Authors: Asthana A. N. , Dube S. D. , Tiwari P. N. , Gambhir P. N. , Rajan T. S.
Published: October 2008

Oil content (percentage) was determined by pulsed nuclear magnetic spectrometry to study its variability in rai (Brassica juncea) and yellow sarson (B. campestris). Wide inter-varietal and intra-varietal variability was observed in both crops. Genetic aspects of oil content were also worked out, and single-plant and bulk selection methods used for 3 years to exploit the intra-varietal variability. A positive trend in the improvement of oil percentage was observed in 27 out of 30 varieties, some of which showed significant improvements over their respective unselected stocks. A maximum increment of 7% was observed in variety BR 40 of rai and 6% in variety YSM of yellow sarson.
Pigeonpea (Cajanus cajan) as a Winter Crop in Peninsular India
Authors: Narayanan A. , Sheldrake A. R.
Published: October 2008

Pigeonpeas (Cajanus cajan) are normally sown in June or July in India, at the beginning of the monsoon, but trials were carried out at Hyderabad by sowing in October or November as a winter crop. The duration of the crop, especially of the ‘medium’ and ‘late’ cultivars, was much reduced. In 1975–76, October-sown pigeonpeas gave yields comparable to those of the normal season but much lower yields were produced by planting in November 1975. ‘Medium’ and ‘late’ cultivars significantly outyielded early ones. Optimum plant populations for winter crops were 3–5 times higher than are normally used in the monsoon. Pigeonpeas at relatively high population densities could have considerable potential as a winter crop in peninsular India.
Effects of Morphactin (Chlorflurenol) on Sex Expression, Yield and Carbohydrates in Corn (Zea mays)
Authors: Bisaria A. K. , Narang Ranjana , Rastogi G. R. , Bhatnagar V. K.
Published: October 2008

An aqueous solution of a morphactin (chlorflurenol) was applied at 100–1000 ppm to plants of corn (Zea maysL.) variety White Ganga-2 to examine its influence on growth, sex expression, yield and carbohydrates in the grain. At concentrations up to 600 ppm morphactin decreased height, weakened apical dominance, increased the number of tillers and thickness of stem, and caused an appreciable increase in female sex expression, yield and carbohydrates in the grain but reduced them at 800 and 1000 ppm.
Effects of Fertilizer and Clipping on protein in Leaves of Desert Grasses
Authors: Kathju S. , Shankarnarayan K. A. , Lahiri A. N. , Vyas S. P.
Published: October 2008

The effects of nitrogen fertilization and cutting intervals on extractable protein have been studied in three arid zone grasses, viz.Cenchrus setigerus, C. ciliarisandLasiurus sindicus. Depending on the number of cuts and soil fertility status, maximum protein could be harvested fromC. ciliarisfollowed byC. setigerusandL. sindicus. It is concluded that the maximum yield of leaf protein per unit area of land can be achieved with short intervals of cutting coupled with the application of nitrogenous fertilizer.
Problems of Potato Varieties in India
Authors: Pushkarnath
Published: October 2008

Problems of potato culture are discussed with respect to photosensitivity, seed stock degeneration, and the maturity behaviour of varieties bred in the temperate world. Varieties adapted to temperate climates, when grown under sub-tropical conditions, matured earlier and yielded less than when grown under temperate conditions. The complex problems involved in combining several desirable attributes in a variety are discussed in the light of current breeding procedures and new approaches to solve several of the problems are indicated. Data on the bionomics of aphid vectors of potato viruses suggest methods for maintaining high health standards in breeders' stocks. Techniques are discussed for raising large populations of seedlings from true seeds under sub-tropical conditions.
The Foliar Composition of the Oil Palm in West Malaysia
Authors: Chin Poon Yew , Varley J. A. , Ward J. B.
Published: October 2008

Total and partial correlations are presented between foliar nutrients in a uniformity trial. The method of principal component analysis is applied to the correlation matrices, comparing values for three fronds (3, g and 17). The results are also compared with values obtained elsewhere, and the use of principal components in relating yield to foliar composition is illustrated.
Fertility Studies on a Sandy Loam in Semi-Arid Tanzania
Authors: Anderson G. D.
Published: October 2008

Initial and residual effects of phosphorus, lime and potassium were studied on Natal Common and Dodoma Bold groundnuts. Double superphosphate (D.S.P., 42% P2O5) considerably increased yields of the first two crops. Lime was noticeably beneficial on Dodoma Bold but less so on Natal Common, while K depressed yields of both when applied without P. The LPK treatment yielded best with each variety, but initially P alone was most economic. Comparing D.S.P., Tororo superphosphate (T.S.P., 21% P2O5, 13% S) and Minjingu phosphate (M.P., 15% citric soluble P2O5), T.S.P. gave the best response (625 lb/acre over 3 years), more than double that of equivalent P2O5 as D.S.P. T.S.P.'s superiority is attributed mainly to its sulphur content. Though initially inferior, M.P. proved as good as D.S.P. over 3 years. 224 lb/acre T.S.P. in alter-nate years is recommended. After two or three crops, light applications of lime and potassium together would be beneficial.
Soil Fertility under Continuous Cultivation in Northern Nigeria
Authors: Heathcote R. G.
Published: October 2008

Soil acidity, incipient potassium deficiency, and a deficiency of one or more trace elements were limiting factors in three trials of long-term soil fertility changes under continuous cultivation in the Sudan Savanna zone of Nigeria. The effectiveness of organic manures is explained largely or wholly in terms of these factors, since no evidence has yet been found to suggest that the addition of organic matter as such is of value.
Experiments on the Fertilization of Dry Rice (Hill Padi) in Sarawak, Malaysia
Authors: Dunsmore J. R.
Published: October 2008

Shifting cultivation of dry rice on steep hill-sides continues to be widely practised in Sarawak, Malaysia. Fertilizer experiments have shown that economic increases in yield can be obtained by mixing 0·9 kg. (2 lb) of mono-ammonium phosphate pellets (11 per cent N: 21 per cent P) with 2·4 kg. (5·3 lb) of seed just before dibbling. In certain areas additional increases might be gained by further increasing the rate of application of phosphorus, from the use of potassium, and from top-dressing with nitrogen. Closer spacing (30·5 cm. or 12 in. square) than that traditionally used should also increase yields per unit area.
Effects of Variety, Season and Maturity on Yield and Quality of Single-Harvest Snap Beans
Authors: Palevitch D.
Published: October 2008

The quality of bean pods was influenced to a large degree by the variety, season of planting and the precise time of harvesting. The varieties Tenderette, Executive and Bush Blue Lake 274 were outstanding in their concentrated yield and pod quality. The development of seeds in the pods was faster in beans planted during the spring than in the autumn. Thickening of the pods during ripening was more rapid in the autumn than in the spring season. Outstanding differences were found between varieties with regard to the speed of seed development during pod ripening. As opposed to the outstanding differences between varieties with regard to quality characteristics, the differences with regard to yield were generally small and without economic importance.
Effects of CCC on Bread Wheat in Kenya
Authors: Seitzer J. F.
Published: October 2008

CCC applied to bread wheat, in 1967 and 1968 as a foliar spray at 1·40 and 2·28 kg./ha. a.i., prevented and/or delayed lodging to some extent. However, this effect was small and complete control of lodging seems to be unlikely, even when using large amounts. CCC increased grain yields, by 1·5 to 10·9 qu./ha., depending on the extent to which lodging was reduced. Significant depressions in yield were obtained, presumably owing to an observed increase incidence in ear diseases, particularly Septoria nodorum. The increase in grain yield was due mainly to an increase in 1000 grain weight and grains per ear, whereas the effect on tillers per unit area was slightly negative. Where no lodging occurred, there was a slight but non-significant tendency for increasing grain yields after CCC treatment.
Foliar Analysis of Tea
Authors: Willson K. C.
Published: October 2008

The literature for the past seventy years describes a variety of methods of sampling tea leaves, in some of which analytical data from samples have been suggested as capable of widespread use as a measure of the nutritional status of tea plantations.
Correlative Analysis of Yield and its Components in Maize
Authors: Nair K. P. Prabhakaran , Singh R. P.
Published: October 2008

At Pantnagar, India, linear response in maize to nitrogen application was observed up to 150 kg. of N/ha. with some of the most promising hybrids and composites released by the All India Co-ordinated Maize Improvement Programme. Increase in grain yield, and total nitrogen accumulation in grain, were substantially more in Ganga 2 than in the local cultivar or the composites, at higher rates of N application. In absolute terms, the local cultivar accumulated more nitrogen in its grain, but the relative amounts declined at higher rates of N application. Among the yield components influencing ultimate grain yield, barrenness exerted a negative influence on grain yield through the number of cobs per plot. Among cob characters, such as thousand grain weight and number of grains per cob, the former exerted a substantial influence on grain yield.
Effects of Time of Sowing and Phosphamidon (Dimecron) on Cowpea (Vigna unguiculata)
Authors: Enyi B. A. C.
Published: October 2008

Application of dimecron to cowpea plants increased grain yield, its effect being more pronounced in widely spaced plants and those planted in March. Dimecron increased grain yield by encouraging greater leaf area development, by increasing the number of flowering inflorescences and the number of pods set per inflorescence, and by decreasing the number of shrivelled pods. March planting encouraged greater dry matter production than January and May planting. Dimecron application decreased the number ofOotheca beningseni, reduced the proportion of leaf damaged by these insects, and reduced the number of plants infested with aphids and Acidodis larvae.
Relations of Yield Components in Sesame
Authors: Osman H. El Gizouli , Khidir M. Osman
Published: October 2008

Simple, partial and multiple correlations, as well as regression coefficients, were worked out for 14 quantitative characters in a collection of 42 sesame varieties grown for two consecutive seasons. Total number of seeds per plant, number of pods per plant, plant height, height to the first pod and days to flowering and maturity, gave positive and highly significant correlation coefficients with yield and with one another. Partial regression and partial correlations indicated that the number of pods per plant and plant height are important yield-contributing characters.
A Measuring Scale for Areas of Cereal Leaves
Authors: Owen P. C.
Published: October 2008

A method is described for constructing a direct-reading scale for leaf area measurement of cereals. The scale is constructed from linear dimensions of leaves, and it enables rapid non-destructive measurements to be made.
The Agronomic Efficiency of the N.I.A.E. Mechanized Tied Ridge System of Cultivation
Authors: Dagg M. , Macartney J. C.
Published: October 2008

A tied ridge system of hand cultivation has been practised successfully in parts of Tanzania for many years. Equipment to mechanize this system was devised and constructed by the National Institute for Agricultural Engineering, U.K., particularly for use in areas of marginal rainfall where water conservation is essential. Agronomic trials with this equipment were carried out on three soil types in Northern Tanzania. Records from resistance units showed much better penetration of rainfall under tied ridges than under flat cultivation. Corresponding yield responses in maize were only obtained when the increase in available water made an appreciable difference to conditions of water stress at the time of tasselling and silking. Weeding operations using a ridging body achieved a satisfactory control. After a few modifications to the equipment, especially the incorporation of a small tine to rip the bottom of the basins to improve infiltration, the system of cultivation based on ripping, ridging and tieing proved to be an adequate alternative to ploughing and harrowing for seed bed preparation, and a much more efficient method of water conservation.