bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grain and Forage Yield and Stover Quality of Sorghum and Millet in Low Rainfall Environments
Authors: Youngquist J. B. , Carter D. C. , Clegg M. D. 
Published: October 2008

SUMMARYThe potential for using sorghum and millet crop residues as fodder was studied in southeastern Botswana. This region is characterized by low, unevenly distributed rainfall and shallow sandy soils. There were significant differences among cultivars for grain and stover yield, digestibility, crude protein, and mineral content, but no species advantage. Stover from all entries was adequate for cattle maintenance inin vitrodry matter digestibility (IVDMD) and most of the minerals tested, but crude protein and phosphorus levels did not always meet the minimum requirement. The deficient phosphorus levels were compounded by high calcium levels. This mineral imbalance could lead to bone abnormalities and reduced fertility in livestock.
Root Response to Water Stress in Rainfed Lowland Rice
Authors: Thangaraj M. , O'Toole J. C. , De Datta S. K. 
Published: October 2008

SUMMARYThe relation between soil mechanical impedance as a result of soil drying, and root system growth (mass and length density) of rice was investigated in greenhouse and field studies. In a greenhouse experiment, soil drying for 16 days increased mechanical impedance in the 0–20 cm soil layer from near 0 to 2.5 MPa, and decreased root growth by 47% compared to the continuously flooded control. Root length density decreased with decreasing soil moisture and increasing soil mechanical impedance. In a lowland field experiment using a sprinkler irrigation gradient treatment for 19 days during the vegetative growth stage, soil mechanical impedance as low as 0.01 MPa inhibited root growth while values greater than 0.3–0.5 MPa decreased root growth and extension by 75%. The relative loss of potential root growth was continued after reflooding. Root length density, measured at flowering, was linearly related to yield.
Time and Method of Weed Control in Pearl Millet
Authors: Singh Rajinder , Yadav S. K 
Published: October 2008

SUMMARYField experiments during the rainy seasons (July–October) of 1984 and 1985 at Hisar, India showed that removing weeds in pearl millet from 10 to 60 days after sowing led to fewer weeds at harvest, and significantly higher grain yields were obtained when weeds were removed 20 days after the crop was sown. All the weed control methods tried (hand hoeing, hand wheel hoeing, or application of terbutryne or atrazine) were successful and significantly increased crop growth and grain yield. The maximum grain yield was obtained with atrazine at 0.5 kg ha−1 and the minimum in the unweeded control.
Photosynthesis of Cassava (Manihot esculenta)
Authors: El-Sharkawy Mabrouk A. , Cock James H. 
Published: October 2008

SUMMARYIn recent studies of cassava at CIAT, net CO2uptake rates of 20 to 35 μmol CO2m−2s−1were commonly observed. Cassava photosynthesis has a high optimum temperature (35°C) and a wide plateau (25 to 35°C) corresponding to the temperature range under which cassava is cultivated. Leaf photosynthesis requires high saturation irradiance (1500 μmol m−2s−1) and the rates are greatly reduced by leaf-air vapour pressure differences above 1.5 kPa; this reduction is associated with stomatal closure. Cassava leaves have low photorespiration, low CO2compensation point, high percentage of carbon fixation in C4acids and a high PEP-carboxylase activity (15–35% of that in maize), but cassava does not have the typical ‘C4-Kranz’ anatomy. Field measurements of single leaf photosynthesis among a wide range of cultivars grown under rain-fed conditions showed that when light interception was not limiting, there were significant correlations between leaf photosynthesis, total biomass and root yield. This suggests that the use of parental materials with high photosynthetic capacity, in combination with other yield determinants, could be a successful strategy for developing high yielding cultivars. This might be done by exploiting any genetical variations in leaf anatomy and biochemistry that could enhance photosynthesis efficiency and hence productivity.
The Digestibility of Fodder Maize and Maize Silage
Authors: Harris C. E. 
Published: October 2008

SUMMARYThe dry-matter and organic-matter digestibilities of eight samples of fodder maize and five samples of maize silage were measured, using sheep. The maizes were harvested and ensiled in such a way that comparisons could be made between the digestibilities of either the same maturity types, harvested on different dates, or of different maturity types harvested on the same date, or of maize and silage made from similar material. The total range of organic matter digestibility for all types of maize on all dates was within the range 70·6 to 75·2 per cent. The digestibilities of maize silages were found to be slightly lower than those of the original materials.
Effects of Ground Covers and Fertilizers on Establishment and Yield of Cocoa on Clear-Felled Land in Ghana
Authors: Acquaye D. K. , Smith R. W. 
Published: October 2008

SUMMARYAn experiment is described on the establishment of cocoa on clear-felled land, using various ground covers on which 22 NP:KMg factorial treatments were later superimposed. Growth of cocoa was improved in mulched and clean-weeded plots and the unshaded trees began bearing two years after planting, which is exceptionally early for young cocoa in Ghana. In the third year responses to NP fertilizer were obtained and in the following year yields were very high, up to 2170 pounds dry cocoa per acre. This was partly responsible for K deficiency, particularly in plots without mulch and KMg, which led to declining yields especially on the NP plots. Significant increases were thence obtained from the KMg fertilized plots. Mulching at the rates used in this experiment is too expensive and uneconomic, but K fertilizer applied at rates higher than the present rate of 75 lb K2O/acre/annum may be needed on Ghanaian forest soils if they are clear-felled for growing unshaded cocoa.
Effects of Grass Mulch on Groundnuts in the Gambia
Authors: Ashrif M. I. , Thornton I. 
Published: October 2008

SUMMARYThe effect of grass mulch on groundnut yield and shelling percentage has been studied at three locations in the Gambia. Yield increases have been mainly attributed to physical factors but residual increases were found for only one year after application. Mulching gave rise to significant increases in exchangeable soil potassium, in percentage potassium in the plant at harvest and in total potassium uptake by the plant. In the absence of response to potassium fertilizer, increased uptake was ascribed to luxury consumption. It was suggested that reduced shelling percentage from mulched plots was due to potassium-calcium antagonism.
Integrating Agronomic and Economic Perspectives into the Diagnostic Stage of On-farm Research
Authors: Byerlee Derek , Triomphe Bernard , Sebillotte Michel 
Published: October 2008

SummaryCrop production surveys, which integrate the collection of data on both agronomic and economic variables, are increasingly common in on-farm research. A conceptual framework for designing and analysing such surveys is provided. Methodological issues in conducting crop production surveys are reviewed with respect to type of information collected, level of field observation, degree of quantification, frequency of observation, sampling, measurement of yields and yield components, and analysis of yield limiting factors. It is concluded that, while better integration of agronomic and economic perspectives in diagnosis may increase costs, the information and analysis obtained have considerable potential to improve the efficiency of experimentation.
Farming Systems Adaptive Research: Achievements and Prospects in Southern Africa
Authors: Low Allan , Waddington S. R. 
Published: October 2008

SummaryFarming Systems Adaptive Research (FSAR) has contributed much to the understanding of maize production constraints on smallholder farms in southern Africa in the last six to eight years. But its production impact has been constrained by the often inappropriate technology available to FSAR from component research and the ineffective use of its results by extension staff. However, FSAR has demonstrated the utility of a problem (client) orientated approach to technology development, which is now being taken up by some maize commodity research and extension programmes, though effective linkages have not usually been developed. Nevertheless, experience in southern Africa suggests that the FSAR approach can provide a framework for developing more effective integration between key groups involved in technology generation, dissemination and support.
Control of Grain Yield by Sink Capacity and Assimilate Supply in Various Rice (Oryza sativa) cultivars
Authors: Fukai S. , Li L. , Vizmonte P. T. , Fischer K. S. 
Published: October 2008

SummaryThe objective of this study was to identify whether grain yield in four contrasting rice cultivars is limited by supply of assimilate to fill the grains or by sink capacity to accept the assimilate. Grain yield was limited mostly by sink capacity, with little variation in single grain weight among cultivars, but an old cultivar showed some ability to adjust single grain weight. Sink capacity was very sensitive to variation in assimilate supply immediately after anthesis. Reduction in assimilate supply in the anthesis to early grain filling period reduced filled grain percentage and grain yield, particularly in high yielding cultivars with a large number of grains per panicle.
Effect of Intensity and Timing of Defoliation on Growth, Yield Components and Grain Yield in Maize
Authors: Yao N'Guettia R. , Yeboua Kabrah , Kafrouma Angbonou 
Published: October 2008

SummaryEarly season defoliation of maize significantly reduced plant height and leaf area index but leaf number and leaf emergence rate were not affected. Ear development was significantly affected by both early and late season defoliation although tassel development was barely influenced. Silk growth was the phase of ear development most sensitive to defoliation. Early season defoliation significantly reduced all yield components, leading to yield losses ranging from 54 to 100%. The position of the leaves which were removed had an important effect on the final grain yield. Harvest index was affected by both the intensity and timing of defoliation.
Effect of Sowing Date on the Growth and Yield of Lentil in a Rainfed Mediterranean Environment
Authors: Silim S. N. , Saxena M. C. , Erskine W. 
Published: October 2008

SummaryThe effect of advancing the sowing date from early February to November on the growth and seed and straw yields of three large seeded and three small seeded lines of lentil (Lens culinaris) was studied under rainfed conditions in northern Syria between 1982 and 1985. The average seed and straw yields from early winter sowing were 838 and 2476 kg ha−1 compared with 679 and 1470 kg ha−1, respectively, from a late sown crop. There were seasonal differences in the advantage in seed yield from early sowing, largely because infestation by Orbanche species limited the use of early sowing. There were no overall differences between the growth and yields of large and small seeded lines, but genetic variation within groups was apparent for all characters. A high rate of dry matter accumulation, manifested as early vigour, was always related to a high final economic biomass.
Responses of Tea (Camellia sinensis) to Irrigation and Fertilizer. I. Yield
Authors: Stephens William , Carr M. K. V. 
Published: October 2008

SummaryThe yield responses of clonal tea (Clone 6/8) to irrigation and fertilizer were studied in a field experiment (based on the line-source technique) at a high altitude site (1840 m) in the Southern Highlands of Tanzania over a three-year period. In this area (latitude 8°33′S) the annual dry season can last up to six months with potential soil water deficits reaching 600 to 700 mm. In the third year of the experiments yields for the fully irrigated, well fertilized (375 kg N ha−1) treatments had reached 4.9 t ha−1 of made tea. These were reduced by about 2.9 kg ha−1 for each mm increase in the potential soil water deficit. For tea with little or no fertilizer applied the loss of yield was about 1.4 kg ha−1 mm−1. These figures provide a basis for assessing the potential benefits from irrigation where other factors, such as large saturation deficits of the air, do not restrict shoot extension and yield. Yield responses to nitrogen (applied as N:P:K 20:10:10) were essentially linear up to a maximum of about 375 kg N ha−1 in the fully irrigated plots, and 300 kg N ha−1 for the unirrigated plots. Irrigation increased the proportion of crop harvested during the dry season, up to 45% in the fully irrigated treatments. The commercial implications of these results for ‘high’ and ‘low’ input producers are discussed.
Effects of Sweet Potato Virus Disease (SPVD) on the Yield of Sweet Potato Genotypes in Cameroon
Authors: Ngeve J. M. , Bouwkamp J. C. 
Published: October 2008

SummarySweet potato virus disease (SPVD) causes strap-shaped leaves, vein-clearing, puckering, chlorosis and stunting in susceptible sweet potato varieties and yields are much reduced. To investigate the tolerance of genotypes and obtain a better appraisal of yield loss caused by SPVD, eight sweet potato varieties showing symptoms of SPVD were studied for two years in an area where SPVD is severe. Two varieties, although showing symptoms, were tolerant of the disease; their yields were not significantly depressed by SPVD. Among the remaining six varieties, storage root fresh yields were reduced by 56–90% in plants showing SPVD symptoms. Marketable yields, as well as total and marketable numbers of storage roots were similarly depressed by SPVD in the less tolerant varieties. Significant correlations were found between disease severity rating and yield reduction among cultivars.
Improving Productivity of an Upland Rice and Maize System: Farmer Cropping Choices or Researcher Cropping Pattern Trapezoids?
Authors: Fujisaka Sam 
Published: October 2008

SummaryCropping systems research to improve the productivity of an acid upland rice and maize-based farming system is described and evaluations by co-operating farmers are presented. Farmers rejected introduced patterns. The cropping choices of non-cooperating farmers are described in terms of cost–benefits and the reasons underlying their decisions. An approach that combines an understanding of farmers' systems in order to conduct focused research on the weak points of such systems, together with an evaluation of farmer technology and adaptation, may be more effective than researcher-designed, farmer-implemented cropping pattern trials.
A Comparison of Natural Rock Phosphate with Imported Cotton Fertilizer in Cotton/Cereal Rotations in Mali
Authors: Kagbo Robert B. 
Published: October 2008

SummaryOn-farm trials were carried out in the Operation Haute Vallée project, Mali, to assess the possibility of replacing, partially or entirely, imported cotton fertilizer with natural rock phosphate from a local source, and to assess the residual effect on maize and sorghum grown after cotton. The maize/cotton sequence, although not normally used by Malian farmers, was more profitable than either pure cotton grown alone or a cotton/maize sequence when local rock phosphate was used instead of imported fertilizer.
The Effect of Tied Ridge Cultivation on the Yield of Maize and a Maize/Cowpea Relay in the Gambia
Authors: Wright J. P. , Posner J. L. , Doll J. D. 
Published: October 2008

SummaryThe growing season in the semi-arid region of West Africa is drought prone and of irregular duration. Two experiments were conducted in 1986 and 1987 to test the effects of flat cultivation and tied ridge cultivation (TRC) on the yields of maize and the component crops of a maize and cowpea relay cropping system. The two research sites, with slopes of 0.05% and 3%, were near Sapu, The Gambia, on an Aridic Kandiustalf in the 700 mm rainfall zone.Both growing seasons had above average rainfall. In both years, maize on level sites showed no response to tillage practices. On the sloped site in 1987, soil moisture 10 and 15 days after the last rain was greater with TRC than with flat cultivation and yields of sole cowpea and maize were 25% and 18% greater, respectively. On the level site, TRC had no effect on residual soil moisture or grain yield. When rainfall was well distributed, tied ridging did not appear to be a viable tillage alternative for maize-based systems on flat land in central Gambia but with modest slopes, tied ridges markedly increased soil water reserves in the 0.15 to 0.60 m depth after maize harvest.
Mixed Planting of Potato Cultivars: Growth, Yield and Leafminer Damage in the Cool Tropics
Authors: Midmore D. J. , Alcazar J. 
Published: October 2008

SummaryThe influence of planting mixtures of two potato cultivars on the incidence of leafminer fly (Liriomyza huidobrensis (Blanchard)) and on damage to potato foliage, and the effect on growth and yield, was studied in two field experiments in coastal Peru. Climatic differences between the two years of the experiments (1983 and 1984) had a greater effect than did cultivar mixtures on adult fly populations and on the numbers of feeding punctures and pupae per leaflet. Mixtures reduced the number of pupae in the tolerant cultivar, but increased it in the susceptible cultivar; in contrast, mixed planting tended to decrease the adult populations and feeding punctures in the susceptible cultivar of each mixture. In neither year did mixture yields or intercepted radiation exceed those of the highest-yielding sole crop, although land equivalent ratios (LER) reached 1.19. Considering the cultivars' different maturity rates and their tuber growth curves, it is probable that the later maturing cultivar of each mixture was able to exploit available light after, and perhaps even before, senescence of the earlier cultivar. Mixed planting of potato could be beneficial but only to farmers who plant both early and late cultivars, under conditions where the early harvest commands a premium price.
An Evaluation ofRhizobiumSurvival in two Carriers new to Sudan
Authors: Elshafie A. E. , Elhussein A. A. 
Published: October 2008

SummaryThe suitability of charcoal and filter mud as carriers for the survival ofRhizobiumisolates at low and high temperatures was investigated. Both carriers were found to be suitable and maintained high rhizobia populations (1.0 × 108rhizobia g−1). In Sudan, inoculants can safely be stored for 6–10 weeks in the ambient temperature (up to 37°C).
Dry Matter and Nitrogen Accumulation and Partitioning in Field Grown Winged Bean
Authors: Weil R. R. , Belmont G. S. 
Published: October 2008

SummaryGrowth and the partitioning of dry matter and nitrogen were studied in winged bean ‘SLS-40’ grown with single stake supports at two sites in Sri Lanka. Plant parts (leaves, petioles, stems, roots, nodules, flowers, green pods, mature seeds, and mature pod-walls) were collected periodically, if present, for up to 32 weeks after emergence. Slow growth up to the seventh week was followed by rapid growth (2.8 g plant−1 day−1) for the next 15–17 weeks. Little leaf senescence was observed and the nitrogen content of the leaf tissue remained close to 45 mg N g−1 throughout growth. The rate of nitrogen accumulation was 2.3–2.7 kg N ha−1 day−1 between weeks 13 and 32. The final accumulation of nitrogen in the above ground material was 280 to 312 kg N ha−1, only 34% of that being in the mature seed. The harvest index for dry matter was 17.5–20% and the dry seed yield almost 2 t ha−1.
Institutionalizing the Farming Systems Perspective in Multi-commodity Research Institutes: The Role of Systems-based Research Groups
Authors: Spencer Dunstan S. C. 
Published: October 2008

SUMMARYResearch institutes in Africa have had limited success in producing new technologies appropriate to the needs of small farmers because of an inadequate understanding of small farmers' goals and resource limitations and over-reliance on the transfer of technologies from other regions. Farming systems research (FSR) is an effective way of improving the focus of scientists on the problems farmers face. Vertically segmented thematic research programmes make institutionalization of FSR difficult within multi-commodity research centres, particularly the International Agricultural Research Centres. The Farming Systems Research Group has proved effective at overcoming such difficulties at the International Institute of Tropical Agriculture. Its organization, operation and effects on the performance of the research programmes are described.
Towards the Reliable Prediction of Time to Flowering in Six Annual Crops. I. The Development of Simple Models for Fluctuating Field Environments
Authors: Summerfield R. J. , Roberts E. H. , Ellis R. H. , Lawn R. J. 
Published: October 2008

SUMMARYDespite numerous altempts, the development of generalixed models capable of accurate predictions of the times from sowing to flowering (f) of crop plants in field environments has remained elusive. Models which seek to correlate;ʃwith various states of environmental factors such as photoperiod,P, and temperature,T, using formal statistical procedures arc often complex. Here, we describe a family of photothermal responses (involving unambiguous parameters and limits) which quantify the linear, non-interacting effects ofPandT notonʃbut on 1/ʃ, i.e. on therateof progress towards flowering. Based on these relations we suggest that the modelling of crop phenology will be simplified, more reliable and more biologically plausible.
The Search for a Viable Alternative to Slash and Burn Agriculture in the Lowland Plains of Bolivia
Authors: Wilkins J. V. 
Published: October 2008

SUMMARYA multidisciplinary team has attempted to find a sustainable alternative to slash and burn agriculture in deciduous forest in the Bolivian lowlands for those who do not have access to tractor power. Farm size ranges from 30 to 50 hectares and labour and capital are major constraints to development. Fertilizers are not used because of their high price. The alternative proposed is that the farm should contain an area of not more than one hectare in alley cropping producing the family's requirements in farinaceous foods and vegetables, and an area, limited by labour constraints, of perennial crops for cash income. The balance of the farm would be in a silvipastoral system producing various tree products, beef and cheese for sale and sheep for home consumption.
Use of Growth Measurements and Foliar Nutrient Content as Criteria for Clonal Selection in Tea (Camellia sinensis)
Authors: Nyirenda H. E. 
Published: October 2008

SUMMARYA selection programme conducted on young clonal tea plants grown in large sleeved bags and in a field trial established criteria for selecting high yielding field clones on the basis of their growth in early years. Bush area, number of branches and shoots per bush, and foliar phosphorus content at the second crop peak were correlated with yield but the correlation between stem circumference at ground level and yield was inconsistent. It is therefore concluded that all these bush and growth characters, apart from stem circumference, may be reliably used to predict and select high yielding tea clones.