bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Shifting Planting Dates and Mulching on Late Blight (Phytophthora infestans) and Drought Stress of Potato Crops Grown under Tropical Highland Conditions
Authors: Devaux A. , Haverkort A. J.
Published: October 2008

Potatoes (Solanum tuberosumL.) in central Africa are often grown between two rainy seasons to avoid late blight infection. The influence of planting date and setaria mulch treatment on soil temperature, soil humidity, late blight development, ground cover with green leaves, intercepted radiation and tuber yield of potato was studied in crops grown at 1850 m above sea level in Rwanda.

The planting dates towards the end of the rainy season resulted in the best yields and these were considerably increased by mulching which retained soil moisture and reduced soil temperature so resulting in a better ground cover. Increased yields in the mulched plots seemed to be due to increased radiation interception rather than to better radiation use efficiency.
Plant Population, Rainfall and Sorghum Production in Botswana. I. Results of Experiment Station Trials
Authors: Jones M. J.
Published: October 2008

General mathematical relations between yield parameters, plant populations and rainfall were developed for an indigenous sorghum from the results of 28 population/row spacing trials conducted at four sites over five seasons. Populations maximizing yield increased from 25 000 to 69 000 plants ha−1 over the rainfall range 200–700 mm (pre-planting to harvest total). Tillering partly compensated for low populations but yields from 10000 plants ha−1 at 300 and 600 mm rainfall were only 80 and 61% of potential maximum, respectively. Row spacing at constant population affected tiller numbers and eventual panicle weights but not panicle numbers, and any yield differences were unrelated to rainfall.
The Effects of Sorghum and Cowpea Genotype and Sorghum Sowing Density in an Intercrop System
Authors: de Queiroz M. A. , Galwey N. W.
Published: October 2008

Five diverse sorghum genotypes were sown at sole crop density and at intercrop density without cowpea and with two contrasting cowpea genotypes, in the post-rainy season at Hyderabad, India. The interaction of sorghum genotype with sowing density was significant for sorghum dry fodder and grain yield, but the interaction of sorghum genotype with cowpea was not, because of compensation between yield components. The likely response of sorghum genotypes to intercropping can therefore be assessed initially from the performance of low density sole crops, followed by assessment in the presence of a single standard cowpea variety.

The cowpea genotypes were affected by the presence of sorghum but not by the sorghum genotype. This suggests that the effect on the cowpea can be ignored when selecting a sorghum genotype for intercropping, and that a cowpea genotype for intercropping can be selected in the presence of a single sorghum genotype. However, these conclusions arc unlikely to apply to rainy season sowings, when sorghum dominates the intercrop more completely.
Effects of Planting Time and Harvest Age on Cassava (Manihot esculenta) in Northern Australia. II. Crop Growth and Yield in a Seasonally-Dry Environment
Authors: Hobman F. R. , Hammer G. L. , Shepherd R. K.
Published: October 2008

Two experiments, one irrigated and one dryland, were conducted at a site having a seasonally-dry, tropical climate. A range of planting times, with sequential harvests to age 24 months, was used to study cassava growth and yield. Very high yields of 35 to 45 tonnes dry matter per hectare were recorded for the irrigated experiment. Water limitation restricted yields to 15 to 26 tonnes in the dryland experiment. Known or inferred environmental controls of the yield-determining factors of growth rate, growth duration, and partitioning of assimilates to harvest-able organs were used to interpret the results and thus derive general guidelines for the timing of planting and harvesting in seasonally-dry environments.
Intercropping Sorghum with Cowpea in Dryland Farming Systems in Botswana. I. Field Experiments and Relative Advantages of Intercropping
Authors: Lightfoot C. W. F. , Tayler R. S.
Published: October 2008

The intercropping objective of the subsistence fanner in Botswana was identified as a need to secure some cowpea production without reducing the yield of the staple crop, sorghum. Field experiments in which sorghum and cowpea were intercropped in several different environments over three years met this objective on most occasions, but cowpea yields were low compared with their sole crop performance. Although intercropping out-performed monocropping by producing some cowpea yield, land equivalent ratios greater than one and higher gross income and cash returns to draught-power (but not returns to labour) the differences were never large and seldom statistically significant.
Studies on Cotton-based Multiple Cropping
Authors: Mandal B. K. , Ghosh R. K. , Das N. C. , Choudhury A. K. Som
Published: October 2008

Studies were carried out at Kalyani during 1982–83 and 1983–84 to evolve a multiple cropping system with cotton as the main crop. Cotton was intercropped with paddy, greengram, blackgram, peanut and soyabean in the rainy season, and these were also grown as solccrops followed by crops of peanut, lentil, chickpea, wheat and mustard, respectively, in the winter season. All plots were subsequently cropped with sesame in the summer season. There was an increase in total grain yield, land equivalent ratio (LER), area time equivalent ratio (ATER) and relative net return (RNR) values when legumes and cereals were intercropped with cotton. The yield of the winter crops grown with the help of residual soil moisture was in the order: chickpea > mustard > lentil > wheat > peanut. Sesame yielded best after the chickpea and blackgram sequence and yielded almost as well after the lentil and greengram. The greatest net return was obtained from the cotton and paddy (1:1) intercrop followed by sesame.
Effects of Crop Maturity, Weather Conditions and Cutting Height on Yield, Harvesting Losses and Nutritive Value of Cereal–Legume Mixtures Grown for Hay Production
Authors: Rihawi S. , Capper B. S. , Osman A. E. , Thomson E. F.
Published: October 2008

The introduction of forage or hay crops into fallow land represents a means of increasing feed supplies for small ruminants in north Africa and west Asia. Such fallows lie between zones planted with food crops and traditional grazing areas. Mixtures of vetch with barley, oats or triticale, and peas with barley, were cut at the 10% flowering, 100% flowering (100F) and full pod (FP) stages of the legume component. Effects of crop maturity, weather conditions and cutting height on yield, the chemical composition of the standing crop and re-growth were measured. Barley–vetch mixtures yielded 8147 kg dry matter ha−1 of standing crop at the FP stage in 1983 but only 2283 kg dry matter ha−1 in 1984 under drought conditions. Hay yields were 4377 and 1640 kg dry matter ha−1, respectively. The highest yielding mixture, grown in 1983, was oat–vetch which yielded 8670 kg dry matter ha−1 of standing crop and 4285 kg dry matter ha−1 of hay at the FP stage. Cutting at the 100F or FP stage maximized dry matter yield and minimized the risk of rainfall prolonging hay making. Rain caused slight damage to some hays cut at early stages of maturity. Voluntary intakes and digestibilities of field-cured hays were determined. The voluntary intakes of triticale–vetch hay at the FP stage and all barley–pea hays were low compared with other hays. Hays contained sufficient estimated metabolizable energy (ME) for use in sheep diets during pregnancy and middle or late lactation. ME values averaged 9.2 megajoules per kg dry matter in both 1983 and 1984.
Controlled environments as an Adjunct to Field Research on Lentils (Lens culinaris). III. Photoperiodic Lighting and Consequences for Flowering
Authors: Summerfield R. J. , Muehlbauer F. J. , Roberts E. H.
Published: October 2008

Six genotypes of lentil (Lens culinaris) were grown in pots in a glasshouse under natural photo-periods of 10–12 h, extended to an inductive photoperiod of 16 h by supplementary illumination from incandescent lamps. The illuminance of the supplementary light was varied by placing replicate pots at different distances from the lamps; it decreased geometrically with distance (i.e. down an illuminance gradient) from about 2000 lux directly beneath the lamps to about 40 lux at a distance of 6 m from them. All genotypes came into flower progressively later as illuminance decreased; those selected in northern temperate regions were especially sensitive, taking about twice as long to flower at an illuminance of 40 compared with 2000 lux. We suggest, however, that these quantitative responses do not reflect differences in sensitivity to illuminance per se, but are the consequences of genotypic differences in sensitivity to photoperiod. The implications of these data are discussed in terms of adaptation to the aerial environment and strategies for screening germplasm and plant breeding in lentils and other grain legumes.
Analysis of Intercrop Experiments in Dryland Agriculture
Authors: Chetty C. K. Ramanatha , Reddy M. Narayana
Published: October 2008

Objectives of different intercrop experiments need to be kept in view while analysing the data from them. There is no single straightforward way of analysing the data and certain situations require innovative approaches. Types of situations that are encountered in dryland agricultural research are exemplified and methods of meaningful analysis and interpretation of data from them are indicated here. Agronomically-sound meanings are imputed for different ways of calculating LER. Use of the concept ‘Staple Land Equivalent Ratio’ for assessing intercrop systems in particular situations is illustrated.
Performance of Triticale in Comparison with Barley and Wheat in a Semi-Arid Mediterranean Region
Authors: Hadjichristodoulou A.
Published: October 2008

Eight triticale lines were evaluated in Cyprus during the period 1977–82 and compared with the best other cereal varieties grown locally. One triticale line was selected which outyielded Athenais barley by 8.3% and Pitic 62 aestivum wheat by 11.4% in drylands, and durum and aestivum wheat by 20% in irrigated areas. Regression analysis showed that Athenais was the best yielding crop in the least productive environments while under medium or favourable conditions triticale gave maximum yields. Number of grains per spike, harvest index and the N content of grain were larger but ear number, 1000-grain weight and N content of straw were smaller in triticale than in barley. The yield component most sensitive to drought was 1000-grain weight.
Effect of Damage by Stalk-Eyed Fly (Diopsis Thoracica) on Yield Components of Rice
Authors: Alghali A. M. , Osisanya E. O.
Published: October 2008

Rice varieties were compared for their response to infestation by the stalk-eyed fly, Diopsis thoracica (West), both when a choice of varieties was available to the pest and when there was no choice. The fly significantly decreased the number of panicles produced (both total and mature), the percentage of tillers with panicles, grain weight and total yield of unprotected plants, and increased the number of immature panicles and time to 50% flowering. Reductions in grain yield of between 2 and 97% were recorded but these losses were unrelated to the percentage of damaged tillers. Production of new tillers did not fully compensate for damaged ones in most varieties. However, photoperiod-sensitive rice varieties were better able to compen- sate for pest damage than most.
Evolution of Grain Legumes. I. Mediterranean Pulses
Authors: Smartt J.
Published: October 2008

The evolution of the Mediterranean pulses, the common pea (Pisum sativumL.), the faba bean (Vicia fabaL.), the grass pea (Lathyrus sativusL.), the lentil (Lens culinarisMedik.) and the chickpea (Cicer arietinumL.), is considered from the points of view of geographic origin and subsequent dissemination. All appear to have originated in the Fertile Crescent, the most significant subsequent spread being to the north of the Mediterranean basin in the case of the common pea and the faba bean and to the east of it in the case of the other three species. The wild progenitor type is known for all species except the faba bean. In the grass pea the extent of divergence between wild and cultivated populations is small, possibly due to its use predominantly for forage and less as a pulse. Considerable divergence has occurred in other species, where use as a pulse is more important.
Studies on the Potential of Winged Bean as a Multipurpose Legume Cover Crop in Tropical Regions
Authors: Banerjee Anjana , Bagchi D. K. , Si L. K.
Published: October 2008

The potential of winged bean as a multipurpose legume cover crop was shown in field trials by its abundant vegetative growth throughout the growing period of two years. Protein contents of the dry matter of the whole plant, vegetable pods, seeds and tubers were in the range 22–34, 25–30, 32–38 and 16–19%, respectively. In a comparison of two cultivation methods, significantly higher yields were obtained from staked plants than from those grown without supports; protein contents, however, remained constant.
Self-Regenerating Annual Forage Legumes for Double Cropping with Irrigated Wheat or Sorghum
Authors: Muldoon D. K.
Published: October 2008

Two relay intercropping systems were investigated on an irrigated clay soil: first, wheat with a self-regenerating summer legume and, secondly, grain sorghum with a winter growing legume. A range of summer and winter legumes were evaluated. Phasey bean (Macroptilium lathyroides), a free seeding annual, regenerated vigorously as the wheat matured in early summer; cut twice after the wheat harvest it yielded (including the wheat stubble) 7.5 t ha−1 dry matter. Low seed production jeopardized the regeneration of other summer legumes. Subterranean clover (Trifolium subterraneum) regenerated under the maturing grain sorghum crop as did snail medic (Medicago scutellata) and woolly, pod vetch (Vicia dasycarpa). Together with the sorghum stubble they yielded 5–6 t ha−1 between sorghum crops. The benefits of including self-regenerating forage legumes in irrigated grain cropping systems is discussed.
A Field Technique to Screen Seedling Emergence of Pearl Millet and Sorghum through Soil Crusts
Authors: Soman P. , Peacock J. M. , Bidinger F. R.
Published: October 2008

A field technique to screen large numbers of pearl millet and sorghum lines for seedling emergence through soil crusts is described. Seeds were sown on raised broad beds in an Alfisol field. The beds were smoothed after sowing with a bed shaper. Thirty five mm of water was applied from two parallel lines of sprinklers at a rate of 14 mm per hour. A crust of relatively constant strength in different tests developed as the surface dried out. The crust was broken in the control treatment with a crust breaker. The ratio of emergence under crust to that under control (c/u ratio) was used to classify the test materials.
Criteria for Clonal Selection in Tea (Camellia sinensis). I. The Relation Between Mother Bushes and their Clonal Derivatives for Bush Area, Shoot Number and Yield
Authors: Nyirenda H. E. , Ridpath V. E. T.
Published: October 2008

Bush area, shoot number and yield were all strongly and positively correlated in 100 young seedling tea bushes. Clones derived from the bushes exhibited characteristics which were correlated with those of the mother bushes, indicating the usefulness of these observations in the selection of clones for improved performance.
Agricultural Production in the Third World - a Challenge for Natural Pest Control
Authors: Hussey N. W.
Published: October 2008

Prevention of the enormous losses of crop production in the Third World, both before and after harvest, would make a substantial contribution to the survival and well-being of countless small fanners. Many attempts to reduce the scale of pest attacks by facilitating the purchase of pesticides and fertilizers have failed in the face of maladministration, mistrust, primitive conditions and ignorance. Yet, despite the difficulties, these fanners have evolved a pattern and practice of production which incorporates many positive attributes which have only recently been appreciated by western scientists. Attention is drawn to some of these methods and also to the benefits and limitations of both classical and manipulated biological control. It is concluded that further improvements depend on the ability of entomologists to adapt some of the concepts widely used in China to utilize scientific techniques within a socio-economic structure where even the plastic bag must be regarded as high technology.
Investigations of Source-Sink Relations in Cassava Using Reciprocal Grafting
Authors: Ramanujam T. , Ghosh S. P.
Published: October 2008

Source-sink relations in cassava were investigated following reciprocal grafting among three cultivars of different yield groups. Both rootstock and scion had significant effects on net assimilation rate and tuber yield, demonstrating that both sink capacity and source activity are important in achieving maximum tuber yield. The scion had no effect on tuber dry matter percentage and starch content of the grafts but the hydrocyanic acid content of the tuber was significantly influenced by both rootstock and scion.
Pattern of Tea Shoot Growth
Authors: Smith R. I. , Harvey F. J. , Cannell M. G. R.
Published: October 2008

Tea shoot development was measured by sequentially sampling shoots from seven clones growing at Nsuwadzi Research Station, Mulanje, Malawi. A Gompertz growth curve best described the increase in shoot length with time, an exponential curve described the relation between dry weight and shoot length, and a quadratic curve related dry weight to fresh weight. The parameters of these curves differed among clones and provide a basis for exploring genetic influences on tea yield. The most rapid elongation of shoots of all clones occurred about 42 days after plucking, considered the optimum age for harvest at Mulanje. Clones selected at Mulanje produced longer shoots with greater dry weight but slightly lower dry matter content per unit stem length than clones selected at Kericho, Kenya. The dry:fresh weight ratio of 0.22 used at Mulanje to calculate dry matter yields was too high for most clones.
Confidence Intervals for Staple and Effective LER Values
Authors: Oyejola B. A.
Published: October 2008

When an intercrop fails to produce a required proportion of the sole crop yield, but produces a yield advantage over the sole crop, the method of sole crop supplementation has been suggested by many authors including Mead and Willey (1980) and Riley (1985). Modifications to the Land Equivalent Ratio (LER), used for assessing yield advantages, have been suggested and referred to as staple LERs (SLERs) and Effective LERs (ELERs). In this paper, a graphical method of estimating the SLER and ELER values (and consequently their yield advantages) is presented. The graphical estimation of the confidence interval for the SLER and ELER values is also shown.
Effect of Five Years of No-tillage and Mulch on Soil Properties and Tuber Yield of Cassava on an Acid Ultisol in South-eastern Nigeria
Authors: Hulugalle N. R. , Lal R. , Gichuru M.
Published: October 2008

The effect of no-tillage and mulch on soil properties and tuber yield of cassava was studied over a five year period on an infertile, acid Ultisol in south-eastern Nigeria. Mulch was applied at a rate of 12 t ha−1as a split application once at planting and once six months after planting. No chemical fertilizers were used during the trial. Bulk density and proportion of micropores (pore radius, r, <1.4 µm) were greater, and proportion of macropores (r>14.4 µm) lower, with no-tillage. Water infiltration was increased by mulching, being greatest in tilled, mulched plots. Soil chemical properties were not significantly affected by tillage system, although levels of exchangeable calcium, magnesium and potassium were higher and acid saturation lower with mulching. Soil physical and chemical properties were best with tillage and mulching, and poorest when neither tillage nor mulch was used. Cassava tuber yield was unaffected by tillage system but increased by mulching.
Training in Farming Systems Research: Review and Prospects
Authors: Tripp Robert , Woolley Jonathan
Published: October 2008

A wide variety of training activites has been carried out related to farming systems research (FSR). The majority have had one or more of the following objectives: to introduce the farming systems perspective, to teach new research methods, and to promote the institutionalization of FSR. Many of these objectives are important, but FSR training is not usefully seen as a separate field of endeavour. The goals of FSR training will be better served by reconsidering the roles of universities, national research institutions, and international institutions.
Studies on Maize (Zea mays) at Bunda, Malawi. III. Yield in Rotations with Pasture Legumes
Authors: MacColl D.
Published: October 2008

Yields of maize were increased when they followed successfully established pasture legumes in two rotation experiments. The largest increases were obtained after silverleaf and were equivalent in one experiment to the effects of about 30 kg N ha−1a−1over four years and in the other experiment to those of 40 kg N ha−1a−1over three years. The largest beneficial effect of some of the legumes was on the first crop of maize but in others did not occur until the third or fourth crop. The possible reasons for the different patterns of residual effect are discussed in relation to the nature of the legume residues, the quality of the seedbed following the legumes, and rainfall
Studies on Maize (Zea mays) at Bunda, Malawi. IV. Further Investigations into the Effects of Planting Date
Authors: MacColl D.
Published: October 2008

Late planting of a 136-day variety of maize led to reduced yields only when planting was later than about four weeks after the start of the main rains. The reductions were caused by drought at the end of the season and by high rainfall in the first 35 days after planting. Drought beginning 80–100 days after planting (DAP) reduced weight per seed but drought beginning earlier than 80 DAP reduced seed number per cob and increased the number of barren plants. Late showers alleviated the reduction in weight per seed but not the other symptoms of drought. High rainfall after planting was associated with reduced plant size at flowering and reduced seed number per cob at harvest.
Stages of Development in Lentil
Authors: Erskine W. , Muehlbauer F. J. , Short R. W.
Published: October 2008

Uniform descriptions of developmental stages in crops improve communication among producers, researchers and others. This paper gives a uniform system for the description of the developmental stages of lentil that we believe is not only universally applicable to all growing environments (field or greenhouse) and to divergent cultivars, but also useful for single plants or communities of plants. Vegetative and reproductive development are described separately. Vegetative growth stages are described by counting nodes on the main stem and continuing the count up the basal primary branch to include the highest fully developed leaf. Reproductive stages Rl and R2 are based on flowering, R3 to R6 on pod and seed development, and R7 and R8 on maturation.
The Critical Zinc Deficiency Level and Response to Zinc Application of Wheat on Typic Ustochrepts
Authors: Bansal R. L. , Singh S. P. , Nayyar V. K.
Published: October 2008

Field experiments at 26 sites, selected on the basis of their varying degrees of zinc deficiency, showed that the critical deficiency levels of zinc for wheat were 0.60 mg kg−1 in the soil and 19 μg g−1 dry matter in 45-day-old plants. Further field trials at nine locations with varying levels of zinc deficiency showed successive increases in the grain yield of wheat with increases in zinc application, emphasizing the need for zinc fertilization when wheat is grown on zinc-deficient soils.
Time to Flowering of Mung Bean (Vigna radiata) Genotypes and their Hybrids in Response to Photoperiod and Temperature
Authors: Imrie B. C. , Lawn R. J.
Published: October 2008

Time to flowering of mung bean crops varies appreciably depending on the genotype, and the daylengths and temperatures prevailing during the period after sowing. Relatively little is known about the precise nature and inheritance of flowering responses to photoperiod and temperature. The combined effects of variations in these two factors on time to flowering were therefore evaluated in controlled environment studies on six genotypes and four F1hybrids. The responses were examined for conformity with hypothesized linear models from which inferences might be made of the genetic control of flowering. The analyses suggest that all the genotypes and F1s tested were quantitative short day plants, with the possible exception of one line which may be day neutral. The analyses further suggest that time to flowering was influenced by four genotype-specific attributes: minimum time to flowering, critical photoperiod (Pc), responsiveness to photoperiod longer than Pc, and responsiveness to temperature. Among the genotypes tested, different values were observed for each attribute. In most instances, the values for the F1s were closer to one or other parent, indicating dominance rather than additive genetic effects. We conclude that, with several levels each, the four attributes provide the potential for a diversity of flowering response types within mung bean. Further, it should prove possible to manipulate the mung bean germplasm to obtain novel combinations of attributes, and thus to breed genotypes adapted to photothermal regimes not previously considered suitable for the crop.
Plants, Genes and People: Improving the Relevance of Plant Breeding in Africa
Authors: Haugerud Angelique , Collinson Michael P.
Published: October 2008

Plant breeders cannot respond to every quirk of farmers' circumstances but the relevance of breeding research in poor nations can be improved. Recent innovations in germplasm screening programmes for developing nations highlight important differences in selection criteria between farmers and scientists, and among farmers themselves. Drawing on the authors' African experience with International Agricultural Research Centres working on maize and potatoes, the paper explores how breeding programmes benefit from an understanding of farmers' own detailed knowledge about the crop varieties they already cultivate. Issues considered include farmers' use of cultivar diversity, the trade-off between yield and maturity class as selection criteria, defining appropriate experimental conditions, and innovative techniques to increase farmer participation in germplasm screening.
Climate and Agricultural Production in Uganda
Authors: Huxley Peter A.
Published: October 2008

The study of climate deals with the analysis of seasonal levels of various meteorological factors which influence us through the aerial environment. Short-term deviations from the expected climatic pattern are described as weather. In agriculture, a knowledge of both climate and weather is an essential basis for the adoption of any farming system and practical farmers all over the world have discovered, by trial and error over long periods of time, patterns of farming suited to their respective climatic areas. In many cases today these farming patterns are no longer economically feasible or socially acceptable and, with the present urgent need for increased agricultural production in the developing countries, there is not time for a leisurely approach to the problem of modifying the systems or finding new ones.
A Cheap Weighable Container for Measuring Evaporation from Alfalfa in the Sudan
Authors: A/Hafeez A. T. , Hudson J. P.
Published: October 2008

Ten weighable containers, the same size as 4-gallon petrol tins, were located in a plot 80 metres from the leading edge of a 2-acre field of irrigated alfalfa growing under advective conditions in the Sudan. Evapo-transpiration from alfalfa growing in these containers was compared with evaporation from a series of small evaporimeters level with the top of the plants and from a standard U.S. Class A evaporation pan, and also with estimates of evaporation calculated by the Penman formula. Evaporation from the free water surfaces in evaporimeters or pan was always greater than from alfalfa in the containers when the crop was 25 cm. high or less, but lower when the crop was more than that height, whilst the figures calculated by the Penman formula were much lower than either. Cumulative water losses were also recorded from containers where the soil was kept wet or allowed to dry out, and these were compared with evaporimeter losses up to the stage where no further water was being lost from the dry containers.
The Interaction of Nitrogen and Water on Yield, Protein and Mottling in Wheat Grown on Black Earth in Queensland
Authors: Wood H. L. , Fox W. E.
Published: October 2008

The effect of available water on yield (e.g. Waring, Fox and Teakle, 1958) and of nitrogen on yield and quality (e.g. Waring and Teakle, 1960) have been examined for wheat grown on black earths of the Darling Downs in Queensland. However, the joint effect and individual contributions of nitrogen and water to this effect in the field appear to have been neglected. Further, the condition known as mottled wheat, described by Wood (1960), is an important problem in the wheat industry, and it was felt by the authors that this condition was the result of a water-protein yield complex. It was therefore decided to examine the effects on yield, total protein and mottling of applications of nitrogen and water in a soil where these were deficient.
The Effect of Organic Matter in Soil on Legume Nodulation
Authors: Masefield G. B.
Published: October 2008

Pot experiments were used to test the effect of incorporating various organic materials in the soil on the nodulation of peas (Pisum sativum). Only farmyard manure gave a consistent increase in the number and weight of nodules, and also in plant growth, increases which were also produced by the aqueous extract of farmyard manure, although none of these increases were as large as those obtained by the addition of a combination of P and K fertilizers or activated vermiculite. Field beans (Vicia faba) and French beans (Phaseolus vulgaris) in general reacted in the same way as peas.
Chemical Studies of Some Nigerian Vegetables
Authors: Oke O. L.
Published: October 2008

Three Nigerian vegetables,Solanum melongena, Solanum nodiflorumandVernonia amygdalinawere analysed for oxalate, cyanide, minerals and food value. The edible leaves were low in oxalate and so involve no danger of oxalate toxicity, or decrease in their nutritive value due to the presence of oxalic acid. The content of hydrocyanic acid was also negligible and would, in any case, be lost during cooking. Aluminium contents were very high and could possibly be regarded as constituting a toxic level. The calcium content would provide about 4–7 per cent of the daily requirement for adults, who could depend solely on these vegetables for their daily iron requiretnents. The leaves were also good sources of protein. All these factors make the vegetables important dietary components in Nigeria and they could serve as a protein supplement, especially in villages where children can not get enough protein from meat, milk and cheese.
Evaluation of a Technique for Stimulating Yield of Hevea brasiliensis
Authors: Anliker W. L. , Scanlon D. H.
Published: October 2008

Use of substituted phenoxyacetic acids as yield stimulants for Hevea brasiliensis has been mainly limited to applications below the tapping cut rather than above. Although the above-cut application of these stimulants has exhibited some advantages with respect to yield, its use has been limited due to undesirable bark renewal characteristics. This paper describes studies with a method of above-cut application of stimulant which appears to eliminate the previous disadvantages. Reduced concentrations of growth regulator, applied at frequent intervals in combination with a disease preventive measure, resulted in favourable yield responses, bark renewal characteristics and application economics. Subsequent bark renewal was apparently directly proportional to the concentration of stimulant applied and it was thus possible to control the degree of bark regeneration. The above-cut method shows promise of being particularly effective with systems of reduced intensity tapping on certain clones.
Improving Genotypic Adaptation in Crops – a Role for Breeders, Physiologists and Modellers
Authors: Shorter R. , Lawn R. J. , Hammer G. L.
Published: October 2008

Approaches using breeding, physiology and modelling for evaluating adaptation of plant genotypes to target environments are discussed and methods of characterizing the target environments outlined. Traditional approaches, and their limitations, to evaluation of genotypic adaptation using statistical and classificatory techniques with a phenotypic model are discussed. It is suggested that a simple biological model is the most appropriate framework in which to integrate physiology and modelling with plant breeding. Methods by which physiology and modelling may contribute to assessment of adaptive traits and to selection for adaptation in a breeding programme are considered.
Responses of Tea (Camellia sinensis) to Irrigation and Fertilizer. II. water Use
Authors: Stephens William , Carr M. K. V.
Published: October 2008

The water use of clonal tea (Clone 6/8) in a line-source irrigation × nitrogen experiment in the Southern Highlands of Tanzania was monitored with a neutron probe during 1987 and 1988 to a depth of 3 m and 1989 to a depth of 5 m. The results for 1989 were used to calibrate a single layer water balance model which was then used to estimate water use for the preceding 1986, 1987 and 1988 dry seasons. In the model evapotranspiration was reduced linearly when the soil water deficit exceeded a critical value of 60 mm. The model predicted water use well for unirrigated, partially irrigated and fully irrigated treatments. Total extractable water was 330 to 350 mm in the 5.5 m deep root zone and estimated annual water use in 1988/89 ranged from 800 mm for unirrigated to 1200 mm for fully irrigated plots, of which about 400 mm was used in the wet season from December to April. Water use efficiencies were between 1 to 4 kg of made tea ha−1 mm−1, increasing with improving water and nutrient status. The slope (b) of the relation between the relative yield loss and the relative reduction in water use was very steep (b = 1.3) reflecting the sensitivity of shoot growth and yield of this clone to water stress.
Effects of Water, Nitrogen and Competition on Growth, Yield and Yield Components of Field-grown Tepary Bean
Authors: Nelson Suzanne C. , Nabhan Gary P. , Robichaux Robert H.
Published: October 2008

The effects of water and nitrogen on growth, yield and yield components of tepary bean (Phaseolus acutifolius) were evaluated at Tucson, Arizona in 1987 and the effects of water and intercrop competition with Sonoran panicgrass (Panicum sonorum) in 1988. Total shoot biornass and reproductive yield were significantly reduced by lack of water in both seasons. Addition of nitrogen had no significant effect on total shoot biomass or reproductive yield in 1987. Intercrop competition significantly reduced total shoot biomass and reproductive yield of tepary bean in 1988. Yield component responses varied slightly depending on treatment and year.
An Agro-Economic Analysis of Field Trials from a Farming Systems Research Perspective: Weed Control in Rainfed Lowland Rice in Senegal
Authors: Posner Joshua L. , Crawford Eric W.
Published: October 2008

Using a farming systems approach, a multidisciplinary team in southern Senegal examined three strategies for weed control in rainfed lowland rice: use of herbicide; replacement of broadcast seeding by row seeding with mechanical seeders; and transplanting compared with direct seeding of rice. Thorough evaluation of the agronomic and economic benefits of these strategies for farmers was facilitated by supplementing the standard analysis of on-farm trials with multivariate analysis incorporating agronomic survey data to explain treatment effects better, and by considering technical and economic effects throughout the farming system. The agro-economic analysis led the team to conclude that: where soils are productive, herbicide use is a profitable investment; when converting to direct seeding, farmers should facilitate weeding by seeding in rows with a mechanical seeder; and transplanting should not be discouraged in areas where it is still feasible, since it is less time-consuming, fits in better with other farm activities and requires less fertilizer.
Identifying Target Groups for Agricultural Research: The Categorization of Rice Farmers in the Dominican Republic
Authors: Doorman Frans
Published: October 2008

A method is discussed for classifying small scale rice farmers from the Dominican Republic who have similar production systems and access to land, but differ widely in the yields they obtain and in the adoption of new technology. The results are used to define two recommendation domains, for farmers with ‘good’ and ‘poor’ production conditions, and to suggest appropriate technology for each. For farmers working in good production conditions the development of a technological package based on the double cropping of semi-dwarf varieties with high yield potential and production efficiency is recommended; for farmers with poor production conditions, a technological package is suggested based on varieties with a high tolerance of drought, flooding and weed development, which yield adequately at low input levels.
Effect of Planting Technique and Planting Density on Yield of Late Planted Sugarcane in North Central India
Authors: Yadav R. L. , Kumar Ravi , Verma R. S.
Published: October 2008

In the wheat–sugarcane rotation, which covers more than half of the growing area in subtropical India, planting of sugarcane is delayed until after the wheat harvest in April–May. This allows little time for the sugarcane to produce tillers and so results in smaller millable cane populations and yields than those from more timely (February–March) plantings. This study considers techniques such as ring and trench planting which might allow a high seed rate to compensate for reduced tillering. Yields obtained using these systems were about 20 t ha−1 greater than from the conventional flat planting method, because of a better distribution of primary shoots from the parent sett and reduced plant competition during the early stage of growth. The cost of cane production was greatest with the ring system and least with the conventional planting method but deep trenches gave the best net return.
The Role of Weeds in the Productivity of Amazonian Bush Fallow Agriculture
Authors: Staver Charles
Published: October 2008

Three effects of herbaceous weeds on the productivity of a bush fallow system cropped with maize, cassava and plantain were identified in four experiments carried out in Central Amazonian Peru. First, early weed control is needed to minimize crop yield reductions. Weeds reduce plantain raceme weight and days to flowering, but not cassava yield, if weeding is done early. Second, fallows must be long enough to reduce weed seed banks to levels tolerable to farmers. While fallows of between two and five years eliminate herbaceous weed biomass present at the beginning of the fallow, weed seed banks decline linearly through ten years of tree cover. Third, with successive clean-weedings to reduce weed competition, tree and shrub numbers and their proportion of total non-crop biomass decline, while the amount and proportion of herbaceous weeds increase. Tree and shrub regeneration is reduced by longer cropping periods, more frequent weedings, greater crop cover, and shorter fallow periods.
Effects of Winged Bean on a Following Maize Crop
Authors: Weil R. R. , Samaranayake A.
Published: October 2008

The effects of winged bean (Psophocarpus tetragonolobus) on a following crop of maize were assessed in two agroecological zones of Sri Lanka. Maize was grown after maize with variable rates of nitrogen fertilizer (0–150 kg N ha−1) or after winged bean or soyabean (Glytine max). Where it could be extrapolated from the nitrogen response curve, the apparent nitrogen contribution by winged bean was 70 kg N ha−1. However, in some cases maize after winged bean yielded more than the maximum yield predicted by the Mitscherlich N-response curve, suggesting the effect of some yield-enhancing mechanism in addition to nitrogen contribution. Where no fertilizer nitrogen was used, maize yields on land which had previously grown winged bean were 52–91% higher than those where maize was the previous crop. Winged bean proved to be an effective green manure crop even when all above-ground plant parts were harvested for food and fodder.
Effects of Age of Harvesting after Pod Set on the Growth, Yield and Quality of Okra (Abelmoschus esculentus)
Authors: Iremiren G. O. , Osara A. W. , Okiy D. A.
Published: October 2008

Differences in the age at which okra pods were harvested (4, 7, 10 or 13 days after pod set) had no effect on vegetative growth or pod yield, but pods harvested more than seven days after pod set were of poorer quality. The reduction in pod quality arose mainly from an increase in crude fibre and a reduction in the moisture, crude protein and ash content of older pods.
The Physiology of Grain Yield in Wheat in an Irrigated Tropical Environment
Authors: Ishag H. M. , Ageeb O. A. A.
Published: October 2008

The potential yield of wheat and the physiological basis of yield limitation in the lowland irrigated tropics was investigated in three cultivars planted at five sowing dates. Maximum grain yields were achieved by cultivars that flowered in January when the weather was coolest. The period from sowing to terminal spikelet initiation was similar for all varieties and all sowing treatments. The period from terminal spikelet initiation to ear emergence was increased when seed was sown in late November or early December rather than in October or early November. Manipulation of the sowing date in relation to the choice of cultivar had a considerable effect on grain yield.

H. M. Ishag and O. A. A. Ageeb: Rendimiento del trigo en las zonas tropicales.
Effect of Mixed Row Cropping of Early and Late Maturing Rice Varieties on Crop Productivity under Intermediate Deepwater Conditions
Authors: Reddy M. D. , Sharma A. R. , Panda M. M.
Published: October 2008

Two early maturing semi-tall (120–130 cm) rice varieties, Kalinga-3 (85 days duration) and Banaprabha (95 days duration), were compared in pure and mixed crop stands under intermediate deepwater conditions (15–50 cm) with a modern late maturing (170 days duration) semi-dwarf (100 cm) variety, CR 1016. Parallel line seeding of CR 1016 and Kalinga-3 or Banaprabha in alternate rows (1:1 ratio) 20 cm apart yielded 19% more grain than a pure crop of CR 1016 alone. Mixed crop planting in a 1:2 or 2:1 ratio or with reduced inter-rovv spacing gave no additional yield advantage. Mixed row cropping prevented lodging in early varieties, whereas monocrops of the same varieties were partially lodged and showed some premature seed germination. The better and more stable yields obtained from such mixed cropping could be beneficial to resource poor farmers growing rice in conditions of excess water.
The Introduction of an Early Maturing Maize (Zea mays) Variety to a Mid-altitude Farming System in Ethiopia
Authors: Negassa Asfaw , Tolessa Benti , Franzel Steven , Gedeno Gemechu , Dadi Legesse
Published: October 2008

A farm survey conducted in Ethiopia in 1986 identified seasonal food shortage as an important problem facing farmers. The researchers proposed the development of an early maturing maize variety to alleviate the problem and by 1988, on-farm trials of a selected variety were initiated. About two-thirds of the farmers retained part of the harvested crop as seed for planting, indicating their strong interest in the variety. Farmer-designed trials were found to be especially effective for obtaining farmers' assessment of the new variety and for monitoring how they incorporated it into the farming system.

Maíl con maduración temprana para Etiopía
Intercropping Ethiopian Trifolium Species with Wheat
Authors: Kahurananga J.
Published: October 2008

Trials were conducted in 1987 and 1988 to test methods of intercropping annual Ethiopian clovers, Trifolium spp, with wheat. Several different clover varieties, sowing methods, plant spacings, planting dates and rates of phosphorus application were compared. Planting in single or double alternative rows 20 cm apart did not affect wheat grain and straw yield but broadcast sowing of Trifolium in wheat rows 20 cm apart reduced wheat yield. The Trifolium species used significantly affected legume yield. Phosphorus fertilizer increased yield significantly, especially that of the legume component. The trials indicated that the intercropping of Ethiopian clovers in wheat has potential under African highland conditions.

Siembra simultanea de trigo/ Trifolium en Etiopía
The Use of Remote Sensing to Assess the Effects of Water Stress on Wheat
Authors: Mahey R. K. , Singh Rajwant , Sidhu S. S. , Narang R. S.
Published: October 2008

Ground-based radiometric measurements in the red and infrared bands were used to monitor the growth and development of wheat under irrigated and stressed conditions throughout the 1987–88 and 1988–89 growth cycles. Spectral data were correlated with plant height, leaf area index, total fresh and total dry biomass, plant water content and grain yield. The radiance ratio (R) and normalized difference vegetation index (NDVI) were highly and linearly correlated with yield, establishing the potential which remote sensing has for predicting grain yield. The correlation for R and NDVI was at a maximum between 75 and 104 days after sowing, corresponding with maximum green crop canopy cover. The differences in spectral response over time between irrigated and unirrigated crops allowed detection of water stress effects on the crop, indicating that a hand-held radiometer can be used to collect spectral data which can supply information on wheat growth and development.

Efectos de lafalta de agua en el trigo
The Distribution of Root Activity in Acid Lime (Citrus Aurantifolia)
Authors: Kurien S. , Goswami A. M. , Deb D. L.
Published: October 2008

The functional distribution of root activity was determined by selective placement of 32P at fixed positions from the base of the plant in five- and six-year-old acid lime (Kagzi Kalan) on Kama Khatta rootstock. Maximum recovery of radioactivity was observed within a 40 cm radius of the plant base and at depths of 24 cm in 1988 and 16 cm in 1989. Most root activity (75–80%) was confined within a radius of 80 cm and a depth of 16–24 cm. Application of fertilizer within this zone is therefore recommended for maximum utilization by the crop.

Actividad de las raíces en la lima acida
Evaluation of Short and Tall Sorghum Varieties in Mixtures with Cowpea in the Sudan Savanna Of Nigeria: Land Equivalent Ratio, Grain Yield and System Productivity Index
Authors: Odo P. E.
Published: October 2008

Physiomorphological differences between crops in binary mixtures can influence grain yield. A two year field study considered intra-row mixtures of two sorghum varieties, one short (KSV4) and one tall (Yarwasha), with cowpea at Maiduguri in Nigeria. The performance of the component crops depended largely on the relative proportion of cowpea and sorghum in the mixtures. Comparison of actual and expected land equivalent ratios suggested that mutual compensation and cooperation prevailed within mixtures in most instances. The system productivity index of mixtures where the proportion of sorghum: cowpea was 1:3 showed that their yield stability was greater than that of other sorghum-cowpea mixtures.

Combination de sorgol caupi en la Sabana del Sudan