bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Defoliation on Sex Differentiation in Oil Palm Clones
Authors: Corley R. H. V. , Ng M. , Donough C. R. 
Published: October 2008

SUMMARYDefoliation affected inflorescence production by oil palms, causing a decrease in sex ratio (ratio of female inflorescences to total) and an increase in abortion rate. Clones differed in response to defoliation. One of seven clones showed no increase in abortion rate; in one clone there was a tendency for female inflorescences to abort in greater numbers than males. The change in sex ratio occurred much sooner after defoliation in some clones than in others, and comparison of flowering records with dissections done at the time of defoliation indicated that inflorescence sex was affected at more than one stage in development. This has important consequences for attempts to predict yields.
A Novel System of Tossa Jute (Corchorus Olitorius) Husbandry for Seed, Vegetables and Fuelwood
Authors: Asaduzzaman S. M. , Bright G. , Brook R. M. , Hussain M. A. 
Published: October 2008

SUMMARYThe implications of a novel system of seed production for tossa jute (Corchorus olitorius), involving late sowing and intercropping with vegetables, were studied in 1989 and 1990. The greatest jute seed yield was obtained from jute-radish intercropping, where radish yielded 12–13 t ha−1 roots and gave the highest average gross margin, although jute-amaranthus intercropping performed marginally better in 1989. This system of husbandry yielded 3–4 t ha−1 of jute stick for fuelwood, which is of great value to rural households, and proved to be a viable means of producing jute seed, vegetables and fuel.
Application of a Maize Crop Simulation Model in the Central Region of Malawi
Authors: Thornton P. K. , Saka A. R. , Singh U. , Kumwenda J. D. T. , Brink J. E. , Dent J. B. 
Published: October 2008

SUMMARYA computer crop simulation model of the growth and development of maize was validated using data sets obtained from field experiments run at various sites in the mid-altitude maize zone of central Malawi between 1989 and 1992. The model was used to provide information concerning management options such as the timing and quantity of nitrogen fertilizer applications and to quantify the weather-related risks of maize production in the region. It was linked to a Geographic Information System to provide information at a regional level that could ultimately be of value to policy makers and research and extension personnel.
On Farm Grass-Legume Pasture Performance in the Peruvian Rainforest
Authors: Reátegui K. , Vera R. R. , Loker W. L. , Vásquez M. 
Published: October 2008

SUMMARYThe possible use of tropical forage legumes in pastures based on Brachiaria decumbens and Andropogon gayanus pastures was tested on farms in the humid tropics region of Pucallpa, Perú. The pastures were established by farmers using manual labour. They were associated with maize in some cases and were normally grown without fertilizers. The pastures were established in areas where fallow regrowth was felled and burnt. These pastures, with grass-alone controls, were incorporated by farmers into their normal paddock rotation and were grazed by dual-purpose cows. Despite the variable terrain and soil conditions, all the pastures established and persisted well. Over a four year period under grazing, the legume contribution to the forage averaged 21% and ranged between 1 and 66%. Desmodium ovalifolium was the dominant legume in paddocks that were not burnt, whereas in pastures regularly burnt to control weeds it tended to disappear and Stylosanthes guianensis was the main legume present. It is concluded that where farmers ensure the maintenance of adequate levels of forage, grass-legume mixtures are a viable and persistent option even if the pasture is occasionally burnt.
Evaluation of the Dry Bean Model BEANGRO V1.01 for Crop Production Research in a Tropical Environment
Authors: White J. W. , Hoogenboom G. , Jones J. W. , Boote K. J. 
Published: October 2008

SUMMARYMicrocomputer-based simulation models are increasingly being recommended as multipurpose tools for agricultural research. Use of a model should be conditioned by an evaluation of its performance and understanding of its limitations. This paper evaluates the responses of the process-oriented growth model for dry bean (Phaseolus vulgaris), BEANGRO V1.01, with an emphasis on the factors related to cultivar differences for production in tropical environments. Simulations of seed yield from beans grown under conditions of a known water deficit showed good agreement with observed data. The qualitative response to plant population resembled that of a field trial, and the model showed the expected linear relation between days to maturity and seed yield. Overall, the results suggest that BEANGRO has utility for certain types of agronomic studies, but that improvements are possible, particularly with respect to prediction of phenology.
Enhancing Soil Nitrogen Use and Biological Nitrogen Fixation in Wetland Rice
Authors: Kundu D. K. , Ladha J. K. 
Published: October 2008

SummaryThe limited fossil fuel reserve available for manufacturing fertilizer nitrogen and the adverse effects of continued use of high fertilizer nitrogen doses on the environment call for a more efficient use of indigenous soil nitrogen. This paper presents several ways of enhancing soil nitrogen use in wetland rice. These involve utilizing nitrogen present in the deeper soil layers, increasing soil nitrogen mineralization rate, decreasing the loss of mineralized nitrogen from the rooting zone, and adjusting rice variety, soil flooding, and transplanting time. To sustain nitrogen fertility and productivity of ricelands, however, the original soil nitrogen levels must be maintained through natural resources like recycled crop residues and enhanced biological N2 fixation. Various ways of stimulating biological nitrogen fixation by both indigenous and exogenous agents are discussed. Since enhancement of soil nitrogen use in rice and maintenance of the original nitrogen level in soil by stimulating biological nitrogen fixation have not been examined together in the field, elaborate field experiments should be conducted to assess the impacts of such combined practices on long-term soil nitrogen fertility and productivity.
Some Design Problems in Crop Experimentation. II. Multiple Blocking Systems
Authors: Pearce S. C. 
Published: October 2008

SummaryThis paper describes the construction, usefulness and randomization of several designs for field experiments in which there is more than one set of blocks, namely: (a) row-and-column designs, in which there are two crossing sets of blocks, treatments being applied to the plots formed by their intersections; (b) row-and-column designs in which factors are applied to complete rows or complete columns, that is, criss-cross (or strip-plot) designs; and (c) split-plot designs, in which the plots in a study of one factor are used as blocks in the study of another. All are examples of a wider class of designs, with many ramifications, said to have ‘simple block structure’. It is suggested here that some of the assumptions underlying row-and-column designs are questionable. Some alternative approaches are indicated.
Statistical Adjustment of Maize Grain Yield for Sub-Optimal Plot Stands
Authors: Kamidi R. E. 
Published: October 2008

SummaryLinear covariance analysis of crop yield data using plot stand as the covariate is not satisfactory when the missing plants are eliminated before maturity. This is because the resulting relationship between yield and plot stand is non-linear. In this paper, a transformation of plot yield data to adjust for sub-optimal stands in circumstances involving interplant competition is examined. A biomathematical derivation and interpretation of the proposed model is provided. An experiment involving two varieties of maize (Zea mays) grown at three locations provided the data used to validate the model. Adjusted genotype mean yield values obtained using the proposed exponential transformation were in agreement with observed values.
A Successful Plant Improvement Programme on Tea (Camellia Sinensis)
Authors: Ellis Rex , Nyirenda H. E. 
Published: October 2008

SummaryThe tea industry in Malawi is the oldest in Africa but in the past had always produced poor quality tea. A plant improvement programme was therefore started in 1956 at the Tea Research Stations in Mulanje. The improvement in made tea quality was assisted by an investigation into the biochemistry of tea fermentation. Early success was obtained with polyclonal seed varieties and the development of clones from field bushes. These were used in cross breeding to produce new progeny clones which are showing a steady improvement in quality and yield. The need for improved yield was recognised as the programme progressed and appropriate selection procedures adopted. Techniques for improved vegetative propagation for field planting, grafting ofseed bearer trees and composite plants were developed. Liaison with the tea industry has been good and all new plantings in southern Africa since about 1975 have been with improved material. The programme is continuing and future prospects are good.
Management of a Continuously Cropped Forest Soil Through Fertilizer Use
Authors: Kwakye P. K. , Dennis E. A. , Asmah A. E. 
Published: October 2008

SummaryPhosphorus, followed by potassium, were the plant nutrients that most limited yields during the third decade of a long-term fertilizer experiment on groundnut, maize and cassava conducted on an Ultisol in Ghana. Application of sulphate of ammonia significantly decreased soil pH, thus reducing crop yields. Superphosphate or mulch applied alone consistently increased the yields of all three crops. Application of potash increased the yield of cassava throughout the cropping period, but the potash × mulch interaction depressed yields in two of the three cropping seasons. Use of crop rotation, grass mulch and fertilizer, including small amounts of lime, enabled crop yields and soil fertility to be maintained at a fairly high level under continuous cropping.
Response of Wheat to Sewage Sludge Applied Under Two Different Moisture Regimes
Authors: Al-Mustafa W. A. , El-Shall A. A. , Abdallah A. E. , Modaihsh A. S. 
Published: October 2008

SummaryA field experiment was conducted from 1989 to 1992 to investigate the effect of sewage sludge applications on wheat yield under different irrigation regimes. The sewage sludge was applied at rates equivalent to 0, 20 or 60 t ha-1whenever the available soil moisture reached 30 or 70%. The results showed a significant response in grain yield and its nutrient content with no significant differences between rates of sewage sludge applied. Much higher responses were obtained under the wet than under the dry regime.
Self-Reseeding Pasture Barley for Mediterranean Drylands
Authors: Hadjichristodoulou A. 
Published: October 2008

SummaryPermanent pastures were successfully established with mixtures of bulks of crosses of Hordeum vulgare ssp. vulgare with ssp.spontaneum (given the name Mia Milia) and with mixtures of natural crosses involving H. vulgare ssp. agriocrithon (given the name Akhera).These crosses were made to exploit the brittle rachis gene of wild barley in order to develop self-reseeding pasture barley. No re-seeding of the pasture was necessary but a light cultivation to cover the seed in the first year of sowing improved plant establishment. No cultivation was necessary in the following years. Genotypes with a tough rachis were rapidly eliminated from the Milia pastures (F2 bulks) because of their poor seed dispersal. Nitrogen and phosphorus fertilizer increased dry matter yield. Levels of seed dormancy in the wild barley were adequate to provide a safeguard against extreme dry weather conditions and other natural hazards. Forage quality was very high, with a crude protein content of 18% and digestible organic matter of 80% in harvested dry matter. Permanent barley pastures that exploit the brittle-rachis gene of indigenous genetic material have considerable potential for increasing the animal-carrying capacity of permanent pastures and marginal cropped lands.
The Use of Manure on Smallholders' Farms in Semi-Arid Eastern Kenya
Authors: Probert M. E. , Okalebo J. R. , Jones R. K. 
Published: October 2008

SummaryThe manure that is returned to croplands each year is an important resource in the subsistence farming systems of eastern Kenya. Measurements on several farms have shown that the manure being used is of very poor quality. Analyses of soil samples from beneath the bomas (small enclosures) where animals are kept indicate that substantial losses of nutrients occur through leaching; ammonia volatilization and denitrification may also be involved. Current practice is to apply the manure at rates that appear to make poor use of this scarce resource. The findings are discussed in terms of what changes to the system may be feasible to reduce losses of nutrients, and to improve the quality of the manure and the effectiveness of its use.
Development in Cowpea (Vigna unguiculata). II. Effect of Temperature and Saturation Deficit on Time to Flowering in Photoperiod-Insensitive Genotypes
Authors: Craufurd P. Q. , Qi A. , Ellis R. H. , Summerfield R. J. , Roberts E. H. 
Published: October 2008

SUMMARYTwenty-nine diverse genotypes of cowpea (Vigna unguiculata) were grown in approximately 30 photothermal environments in Nigeria and Niger, with mean temperatures ranging from 19° to 30°C, photoperiods from 10 to 16 h d−1 and saturation deficits from 0.5 to 3.1 kPa. Twelve of these genotypes were insensitive to photoperiod. The time of flowering of these photoperiodinsensitive genotypes showed a similar response to temperature. Time to flowering was also delayed by mean pre-flowering saturation deficits greater than 1.5 kPa. The implications of these responses to temperature and saturation deficit for phenological adaptation in West Africa are discussed.
Yields of Cocoa Clones in Response to Planting Density in Malaysia
Authors: Lockwood G. , Yin Joe Pang Thau 
Published: October 2008

SUMMARYNinety five cocoa clones were tested in Sabah, Malaysia at planting densities of 1096 and 3333 plants ha−1. Analysis of dry bean yields up to 60 months after planting showed that vigorous clones performed better at the lower planting density, some clones of intermediate vigour performed well at both planting densities and some weak clones performed well at high planting density. The conclusion that optimal planting densities are highly variable has significant implications for procedures in clone selection and suggests that the relation between the yield of a clone and its general combining ability will become clearer once planting density is taken into account.
Competition Effects between Leucaena and Maize Grown Simultaneously in an Alley Cropping System in Sub-tropical Australia
Authors: Jeanes K. W. , Gutteridge R. C. , Shelton H. M. 
Published: October 2008

SUMMARYA field experiment was conducted to assess the effect of competition between a leucaena hybrid and maize (Zea mays L.) when planted simultaneously in an alley cropping system. The leucaena hybrid (a cross between L. diversifolia and L. leucocephala) was planted at hedgerow spacings of 3 and 5.25 m, while maize was planted in rows 75 cm apart between the hedgerows. The spacing between the leucaena hedgerow and maize was varied by removal of 0, l or 2 rows of maize to give three spacing treatments of 37.5, 75 or 112.5 cm between leucaena and maize. A control plot of leucaena alone was also included in the treatments. The growth and yield of individual maize rows were virtually unaffected by the presence of leucaena, but maize had a significant influence on the growth and yield of leucaena. At full maize canopy development, photosynthetically active radiation reaching the leucaena was reduced in all treatments, resulting in a 75% yield reduction in leucaena at the closest spacing. Overall, maize grain yield reached 10.3 t ha−1 in the continuous maize plots (37.5 cm treatment). This was reduced by up to 40% after removal of two maize rows in the closest leucaena row spacing treatment. The implications of these results for the practical establishment of leucaena hedgerows with a maize crop are discussed.
Response of Young Unirrigated Clonal Tea to Nitrogen Fertilizer
Authors: Malenga N. E. A. 
Published: October 2008

SUMMARYThe response to nitrogen of four high yielding good quality clones of tea was investigated on fertile virgin soil. The yields of all the clones examined were maintained without additional nitrogen during the first two years after planting but Clone PC 81 responded to nitrogen in the second year after planting. This was the earliest recorded stage at which seedling or clonal tea had responded to nitrogen in Malawi. The other clones examined all responded to nitrogen in the third year after planting, and the yields of all the clones were substantially increased by the higher rates of nitrogen applied in the early years after planting, though the responses to nitrogen differed between seasons.
Simulating Root System Development of Short-duration Pigeonpea
Authors: Ito Gayatri Devi O. , Matsunaga R. , Tobita S. , Rao T. P. , Vidyalakshmi N. , Lee K. K. 
Published: October 2008

SUMMARYLength and weight of pigeonpea roots were measured weekly in different soil layers and compared with estimates obtained from a root simulation model using daily climatic data, soil physico-chemical properties and dry matter allocation to roots. Daily moisture content and temperature at different soil depths were well simulated using sub-routines from the CERES-Maize model. Daily allocation of dry matter to roots was calculated from logistic functions fitted to the growth data for shoots and roots. Although root length and weight tended to be underestimated by the model, regressions between measured and simulated root growth were highly significant so that the model could, with a few modifications, be used to predict root system development.
Estimation of Technological Needs and Identification of Problems of Farmers for Formulation of Research and Extension Programmes in Agricultural Entomology
Authors: Sabarathnam Ve. , Vennila S. 
Published: October 2008

SUMMARYThe most important technological needs and farmers' problems in agricultural entomology were identified by analysis of data collected from farmers in Tamil Nadu, India. This showed that damage due to leaf hoppers in rice was the most important research need and that due to brown plant hoppers in rice was the most important extension problem.
Flowering in Pigeonpea (Cajanus cajan) in Kenya: Responses of Medium- and Late-maturing Genotypes to Location and Date of Sowing
Authors: Omanga P. A. , Summerfield R. J. , Qi A. 
Published: October 2008

SUMMARYThe effects of temperature and photoperiod on times from sowing to flowering (f) were investigated in medium-and late-maturing pigeonpea (Cajanus cajan). Twelve genotypes were sown in two seasons at seven sites in Kenya, covering latitudes 0–4°S and a wide range of altitudes (50–2000 m), as well as under polythene enclosures constructed at six sites to create warmer temperature regimes (a total of 26 environments). The same genotypes were also sown at monthly intervals and in an artificially extended photoperiod (in the open as well as under polythene) created by incandescent lamps suspended above the plots at Katumani (1°30′S).Times from sowing to flowering varied from 70 to more than 300 days and were associated with variations in mean pre-flowering values of temperature and photoperiod which ranged from 15.2° to 32.7°C and from 12.6 to 15.0 h d−1. Genotypic variation in f in the most inductive regimes (a mean pre-flowering temperature of 24.3°C for the medium- and 20.8°C for the late-maturing genotypes, combined with a mean pre-flowering photoperiod of 12.6 and 12.8 h d−1) ranged from 70 and 76 days and from 85 to 112 days, respectively. There were no photoperiodic effects on f over the range from 12.6 to 13.1 h d−1, but the artificially extended day delayed flowering, especially in the late-maturing genotypes.The relation between l/f and the mean pre-flowering temperature was linear below and above an optimum temperature, To. The genotype-specific parameters derived from these thermal linear rate models based on flowering responses in 26 environments closely predicted l/f and therefore f in an independent sequence of monthly sowings. It was thus responses to temperature below and above To and not responses to daylength which modulated flowering throughout the wide range of natural environments tested within this vast country, even in the late-maturing and most photoperiod-sensitive genotypes.
Use of Leptochloa fusca for the Improvement of Salt-Affected Soils
Authors: Kumar Ashok 
Published: October 2008

SUMMARYThe grass Leptocloa fusca is very useful on salt-affected soils as it can tolerate extremely saline and alkaline conditions, Since its growth is not affected by gypsum application, planting with Leptochloa is a good biological method for the reclamation of alkaline soils. It is also well adapted to the waterlogging encountered on saline and alkaline soils, and improves the soil's physical, chemical and biological properties so that within two or three years many commercial and forage crops can be grown. Leptochloa excretes salts through specialized glands and is therefore reasonably palatable to farm animals. Because of its vigorous growth on alkaline soils it does not allow satisfactory growth of companion trees, especially in the initial years of soil reclamation.
On-Farm Experiments with Sorghum to Assess the Acceptability of New Varieties and Herbicide Treatments
Authors: Debrah Siegfried K. , Sanogo Diakalia , Boadu Fred O. 
Published: October 2008

SUMMARYOn-farm experiments were used for assessing the processing and food value of four promising sorghum cultivars and the willingness of farmers to pay for the herbicide 2,4-D for controlling the parasitic weed Striga hermonlhica in coarse grains. The active participation of farmers in these experiments was useful in determining the conditions under which the improved sorghum cultivars and the herbicide would be most likely to he adopted by smallholder farmers in southern Mali.
Crop Production in a Variable Environment: A Case Study from Southern Zimbabwe
Authors: Scoones Ian 
Published: October 2008

SUMMARYBiophysical and socio-economic variability have several impacts on farmers' cropping strategies in dryland areas of Africa. This study examines data from a communal area in southern Zimbabwe over a seven year period. Variation in the output of different crops, in the pattern of crop mixes, in the diversity of cropping patterns and the level of crop sales is explored. Through contrasts between ecological zones and household wealth status, the analysis helps to explain the range of farm-level risk management strategies employed. Finally, the importance for research and extension approaches of understanding variability, through a differentiated analysis of cropping strategies, is emphasized.