bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Conservation Effectiveness and Crop Productivity of Forage Legume Intercropping, Contour Grass Barriers and Contour Ridging in Cassava on Andean Hillsides
Authors: Leihner D. E. , Ruppenthal M. , Hilger T. H. , Castillo F. J. A. 
Published: October 2008

SUMMARYSoil erosion and the productivity of cassava (Manihot esculenta Crantz) cropping systems, including forage legume intercropping, were monitored under natural rainfall conditions on Inceptisols in southwest Colombia. Trials were conducted over two cropping periods on moderate slopes. The best erosion control and cassava fresh root yields were achieved by sole cropping on contour ridges. Erosion was greater with forage legume intercropping than with cassava sole cropping in the first cropping period but once well established and uniformly distributed, undersown legumes controlled erosion effectively, though yields of cassava were depressed by 40% or more. Dense stands of grass contour barriers decreased erosion to tolerable levels. Lower cassava yields due to reduced cropping area and competition from the grasses could be compensated for by the production of valuable forage and by increasing cassava planting density.
Assessment of the Effects of Environmental Factors on the Response of Wheat to Fertilizer in On-farm Trials in a Mediterranean Type Environment
Authors: Pala M. , Matar A. , Mazid A. 
Published: October 2008

SUMMARYA series of researcher-managed wheat fertilizer trials was conducted on representative farmers' fields across northwest Syria between 1986 and 1990. Wheat grain and straw yields were strongly correlated with seasonal (October-May) rainfall, almost irrespective of soil fertility, crop sequence or fertilizer rate, with a highly significant response to nitrogen fertilizer which increased with increasing rainfall and decreasing initial soil mineral-nitrogen values. These results were summarized in regression equations which express yield in terms of fertilizer rates, seasonal rainfall and their interactions. The equations with applied nitrogen and seasonal rainfall were the most appropriate for determining fertilizer needs. Economic analysis indicated that all fertilizer treatment rates were profitable under existing price conditions and that fertilizer use would still be beneficial for a nitrogen price up to three times higher than that of the price of grain (weight for weight) with a seasonal rainfall of 250 mm, and up to six times higher with a seasonal rainfall of 450 mm.
Responses of Young Tea (Camellia Sinensis) Clones to Drought and Temperature. I. Yield and Yield Distribution
Authors: Burgess Paul J. , Carr M. K. V. 
Published: October 2008

SUMMARYThe yield response to drought and temperature of six contrasting tea clones was studied in a line-source irrigation experiment in Southern Tanzania. The selected clones, all commercially and/or scientifically important in eastern Africa, embrace a range of morphological and physiological types. The bushes were planted in August 1988 and differential drought treatments were imposed for 16 and 13 weeks towards the end of the dry seasons in 1990 and 1991, respectively. The resulting soil water deficits were successfully simulated using a water balance model. Under well-watered conditions Clone S15/10 (from Kenya) gave the highest yield of dry tea, reaching 5600 kg ha−l in the fourth year after planting (1991/92) compared with 3640–4420 kg ha−1 for the other five clones. During the cool season Clone SFS150 (from Malawi) yielded more than Clones 1, 207, 6/8 and K35. Although annual yields decreased curvi-linearly as the maximum soil water deficit increased, single values for the drought sensitivity of each clone could be derived by using stress time as an index of drought. On this basis Clones S15/10 and 207 were identified as being the most sensitive to drought; Clones SFS150 and 1 were drought resistant. The reasons for these differences in yield responses and the importance of determining drought sensitivity over an appropriate time period are discussed.
Improving Crop Production on Salt-affected Soils: by Breeding or Management?
Authors: Richards R. A. 
Published: October 2008

SUMMARYThe area of salt-affected land is increasing because of irrigation practices and changed land use. Breeding crops that tolerate soil salinity and yield well in salt-affected soils, and employing crop management practices to counter salinity, have been proposed to maintain crop productivity. Here, it is argued that neither breeding nor management will adequately counter the effects of salinity. Although both offer the potential to maintain yields for a brief period, it is inevitable that salinity will continue to increase and crop productivity will decline. Only the establishment of a perennial vegetation that will maintain evapotranspiration at high levels all year round on both salt-affected land and recharge areas will halt the increase in salinization.Mejorar la producción en los suelos afectados por la sal
Some Design Problems in Crop Experimentation. III. Non-Orthogonality
Authors: Pearce S. C. 
Published: October 2008

SUMMARYIdeally each block of an experiment should be made up in the same way with respect to treatments, that is, the design should be ‘orthogonal’. In practice that can be difficult to achieve, especially if the blocks have been chosen to fit the fertility pattern of the field. Sometimes it is impossible, in which case each block will have to contain its own selection of treatments. A number of simple and useful possibilities exist.Whatever non-orthogonal design is chosen some of the contrasts of interest (perhaps all of them) will be evaluated less efficiently, but that can be compensated by the smaller error mean-square given by a better blocking system. Also, where blocks do differ in their content, comparing their means will provide additional information about treatment effects. Sometimes the information may be worth the trouble of recovery.Special attention is given in this paper to total balance (including balanced incomplete block designs), supplemented balance, square and rectangular lattices and alpha-designs. The reinforcement of a design is explained and the advantages considered.Problemas de diseño en la experimentación con cultivos. III
An Analysis of the Effect of Climate and Weather on Coconut (Cocos Nucifera)
Authors: Peiris T. S. G. , Thattil R. O. , Mahindapala R. 
Published: October 2008

SUMMARYStudies on the effect of climatic factors such as rainfall, relative humidity, temperature, sunshine hours, pan evaporation, evapotranspiration, solar radiation, vapour pressure and wind velocity on the button shedding, premature nut fall, and final nut yield of coconut, and crop-weather models developed to predict nut yield, are reviewed. The type of data and statistical analyses techniques used and the areas of research poorly addressed under the different topics are highlighted.Efectos de las condiciones climáticas y el tiempo en el coco
Correction of Systematic Errors in Estimates of Transpiration Obtained Using a Constant Temperature Heat Balance Technique
Authors: Khan Ahmed A. H. , Ong Chin K. 
Published: October 2008

SUMMARYField measurements using 30-month-old grevillea trees indicated that the three main sources of error in sap flow estimation can be overcome by: estimating the temperature bias with the gauge heater switched off or covering the whole trunk with 20 mm thick styrofoam sheet and alumimium foil; or by inserting thermocouples in the stem and accounting for radial and conductive heat losses. These corrections reduce gauge error for tree trunks (50–90 mm diameter) from 10–47% to ±7%. In the absence of a large lysimeter, a comparison of sap flow rates was made by attaching gauges to the trunk and a single terminal branch on the same tree.Calibrado del flujo de la savia en los árboles del géneroGrevillea
The Role of Rhizobial Biodiversity in Legume Crop Productivity in the West Asian Highlands
Authors: Materon L. A. , Keatinge J. D. H. , Beck D. P. , Yurtsever N. , Karuc K. , Altuntas S. 
Published: October 2008

SUMMARYThe native rhizobia capable of symbiosis with annually-sown food and forage legume crops in the Turkish highlands were surveyed and estimates made of the numbers and nitrogen fixing efficiency of native Rhizobium leguminosarum with Turkish cultivars of lentil (Lens culinaris Medik.) and vetch (Vicia sativa L.). Native rhizobia were present in medium to high numbers in most samples but the nitrogen fixation efficiency of at least half of the isolates was poor. Vetch was somewhat less specific in its rhizobial compatibility than lentil, suggesting a potential for artificial inoculation to improve the productivity and sustainability of cropping in both species especially in areas of central and eastern Anatolia where legumes are not traditionally grown.Biodiversidad en el Rhizobium leguminosarum
Sample Surveys of Pests and Diseases of Tea in North-East India
Authors: Sen A. R. , Sarkar A. R. , Chakrabarty R. P. 
Published: October 2008

SUMMARYPests and diseases cause appreciable loss to tea in north-east India, but their incidence and intensity of attack vary widely from district to district, and within districts with variation in climate, elevation and the jat (seed-source) of tea. For example, blister blight is a serious disease in Darjeeling and looper catepillar is mainly localized in certain tea estates of the Assam valley. Thus recommendations regarding pesticides and their application in a particular region must be based on a thorough knowledge of the distribution of the diseases or pests in the region. This can best be obtained through sample surveys, planned in representative estates of the region and carried out with the help of trained investigators. Such surveys will also provide basic data on jat, environment and disease, as a guide to experimentation.
Microbial Rotting of Stored Yams (Dioscorea spp.) in Nigeria
Authors: Okafor N. 
Published: October 2008

SUMMARYThe incidence of rotting among three varieties of yams (Dioscorea rotunda, D. alata and D. cayenensis), stored in a yam barn at Ibadan for about four months, was between 0·6 and 68·5 per cent. The micro-organisms which caused rotting on experimental re-inoculation into yam tubers were the fungi, Botryodiplodia theobromae, Penicillium sp., Marcophomina phaseoli, Hendersonula toruloidea and a motile gram-negative orange-red pigmented bacterim, probably Serratia sp. This is the first record of the ability of M. phaseoli, and H. toruloidea to cause rotting in yam.
Effects of Soil, Cultivation History and Weather on Responses of Wheat to Fertilizers in Northern Tanzania
Authors: Anderson G. D. , Houston B. G. , Northwood P. J. 
Published: October 2008

SUMMARYThe nature of the soil, the influence of previous natural grassland, ley, fallow or cultivation, and the weather conditions before and after planting are shown to affect the yield of wheat, and its response to fertilizers, especially nitrogen. Out of seventeen experiments over four seasons, involving nitrogen top-dressings on wheat, thirteen gave economic increases after the application of I cwt per acre of ammonium sulphate nitrate (A.S.N.). Such applications to the first, second or third wheat crops after Rhodes grass (Chloris gayana) ley, or to land continuously cropped for a number of years, nearly always gave an economic increase in grain yield, but on continuously cultivated land, with normal rainfall after planting, an economic return to a second cwt per acre was probable. Following a one-season fallow, economic responses to nitrogen only occurred when the pre-planting period was very wet. Yields of wheat after ley, both with and without applied nitrogen, tended to be superior to those on continuously-cropped land. Responses to phosphorus only occurred in one area, where the importance of applying both N and P, particularly to newly-ploughed grassland, was very evident. Loss of organic matter, and structural deterioration accompanied by lower efficiency in the utilization of water and nitrogen, are probably the main causes of falling yields on soils cultivated for many years. The use of grass/legume leys is suggested as the best means of maintaining these naturally fertile soils in a highly productive state, even though the present returns from the legs themselves may be less profitable than wheat cropping.
Use of Rank Correlation Methods to Determine Food Preferences
Authors: Jowett D. 
Published: October 2008

SUMMARYCertain statistical techniques, useful in collecting and interpreting ordinal data, are described and their applicability in plant breeding explained. It is suggested that these statistical techniques may be particularly valuable to plant breeders in determining taste Preferences. A series of experiments are described, investigating the taste Preferences of the Itero of Uganda, who show a strong preference for a mixture of cassava, sorghum and Eleusine millet for food. They do not apparently prefer white sorghum grains for food, nor coloured grains for beer, although such Preferences have been recorded elsewhere. They dislike maize and Pennisetum millet. It is suggested that an experimental approach to quality in the breeding of tropical food crops is both desirable and possible, using rank correlation techniques.
Responses to Grazing Intensity on the Transvaal Highveld
Authors: Gillard P. 
Published: October 2008

SUMMARYThe productivity of climax and serai grassland in South Africa was compared at three stocking rates with steers. On climax grassland, over nine years, gains per head at one steer per morgen (= 2·12 acres = 0·86 hectare) were not significantly greater than at two steers per morgen. Liveweight gains per morgen were 70 per cent higher at the heavier stocking rate and were 162 lb and 273 lb at one and two steers respectively. On serai grassland, over three seasons stocked at two steers and three steers per morgen, the liveweight gains per steer were significantly less at the higher stocking rate but there was no significant difference in the gains per morgen, which were 366 lb and 318 lb at two and three steers respectively. The liveweight gains on the seral grassland were significantly higher than on the climax grassland at the same stocking rate Calculation of the total digestible nutrients (T.D.N.) has shown that with heavier stocking more T.D.N. per morgen may be harvested on both grassland types. However, with heavy grazing the efficiency of conversion of T.D.N. into liveweight was less. The quality of the sward, measured in per cent crude protein, P2O5 and crude fibre was better at the heavier stocking owing to delayed maturity of the grass when it is continually grazed short.
Factors Influencing the Survival of Propagules of Tall Fescue (Festuca arundinacea Schreb.)
Authors: Miltimore J. E. 
Published: October 2008

SUMMARYPropagules of five tall fescue genotypes, planted monthly, from April to December, made the greatest growth in April and September and the least in December. Despite the diverse geographic origin of the genotypes, there was no indication of interaction between genotypes and daylength. Propagules grew more vigorously when cut just above the basal leaf sheath then when cut to two or three inches in length. The complete removal of roots, which would facilitate planting, did not reduce growth and appeared to enhance the development of new roots. Propagules consisting of two or three culms grew more vigorously than those consisting of a single culm. Accordingly, if propagules were fragile or if survival was poor, two-culm propagules would become established more readily. Genotypes differed in growth rate even when planting weights were kept uniform. Results of this study could be used to reduce the time and cost of vegetative propagation of tall fescue.
Factors Influencing the Survival of Propagules of Tall Fescue (Festuca arundinacea Schreb.)
Authors: Miltimore J. E. 
Published: October 2008

SUMMARYPropagules of 74 genotypes of tall fescue, consisting of parent and progeny groups, were grown in a glasshouse. The number of surviving propagules were determined after one month and at that time, increment weight (growth) and leaf and root weights were determined. Broad-sense heritability estimates were calculated on the whole population and on two individual parent and progeny groups. The criteria measured varied in heritability between groups, but for the 74 genotypes the values had a more limited range from 57 per cent for root weight to 70 per cent for increment weight. Capacity to survive vegetative propagation was dependent on leaf growth and not on root growth or size of propagule. Because of the variation in survival, this characteristic warrants consideration in a selection program where propagation will be utilized for commercial purposes.
ACCOUNTING FOR SPATIAL VARIABILITY IN FIELD EXPERIMENTS ON TEA
Authors: PEIRIS T. U. S. , SAMITA S. , VERONICA W. H. D. 
Published: October 2008

SUMMARYSpatial variability among experimental units is a common problem in field experiments on tree crops such as tea (Camellia sinensis). Spatial variability is partly accounted for by blocks, but a substantial amount remains unaccounted for and this may lead to erroneous conclusions. In order to capture spatial variability in field experiments on tea, six commonly used spatial analysis techniques were investigated: Covariate method with pre-treatment yield as the covariate, Papadakis and the Modified Papadakis nearest neighbour adjustments, Moving means and Modified moving means methods, and Autoregressive method. The data from long-term fertilizer experiments and cultivar evaluation trials, conducted at different locations by the Tea Research Institute of Sri Lanka, were used in the study. Spatial techniques were evaluated by means of their relative efficiency at each location and year. Evaluation of the four neighbour methods analysed in conjunction with the pre-treatment yield, revealed that spatial variability due to both past and current conditions are operative, especially in experiments with large blocks, and could be captured simultaneously. Relative efficiencies averaging 141% clearly indicated that the neighbour techniques in combination with pre-treatment yield would be effective in controlling the experimental error in tea experiments with large blocks (nine plots per block or more). Experiments with small blocks were not affected by spatial variability due to past conditions and only that due to current conditions need to be addressed. Neighbour techniques, on their own, were found to be adequate to capture spatial variability due to current conditions. The modified Papadakis technique was found to be the best with an average relative efficiency of 145%. The techniques investigated in the study can easily be implemented using standard statistical software. The precision of tea experiments could be increased by using covariate analysis with pre-treatment yield and any one of the four nearest neighbour adjustments tested, when the block size is large; and modified Papadakis technique, on its own, when the block size is small.
BIOMASS AND CAFFEOYL PHENOLS PRODUCTION OFECHINACEA PURPUREAGROWN IN TAIWAN
Authors: CHEN C. L. , ZHANG S. C. , SUNG J. M. 
Published: October 2008

SUMMARYEchinacea purpureahas been introduced in to Taiwan and grown successfully. However, information regarding the effects of the growing climate on its active constituents (e.g. caffeoyl derivatives) and biomass production is very limited. In this study the biomass of field-grownE. purpureaplants harvested during three different crop seasons was compared. The content of caffeoyl phenols and the production of aerial plant parts were also assayed. The results indicated that both morphological and agronomic traits were affected by crop season, with spring-grown plants producing more stems and flowers but fewer leaves than autumn-grown plants. Autumn-grown plants produced more caffeoyl phenols, particularly cichoric acid and caftaric acid, in leaf and flower tissues than spring grown plants. Thus, transplantingE. purpureaseedlings in the autumn and harvesting the aerial parts at the beginning of winter first, and then harvesting the rhizome-regenerated plants again in the following summer are technically feasible. This farming system would give commercial cultivation ofE. purpureain Taiwan a great competitive advantage over other growing regions, provided that an environmentally suitable population is selected and established in Taiwan.
EFFECTS OF GRAFTING ON TEA 1. GROWTH, YIELD AND QUALITY
Authors: TUWEI G. , KAPTICH F. K. K. , LANGAT M. C. , CHOMBOI K. C. , CORLEY R. H. V. 
Published: October 2008

SUMMARYTrials in Kenya have shown that yields of tea clones can be increased significantly by grafting onto suitable rootstocks, with the best combinations giving profitable yield increases compared to straight cuttings. However, stock × scion interactions were significant, and not all clones gave useful responses to grafting even onto the best rootstocks, so combinations must be tested individually before commercial planting is considered. The effect of grafting was to increase the number of shoots harvested, with little change in mean shoot weight. Grafting had little or no effect on quality of the tea produced. Attempts to find a method of identifying good rootstocks without testing them in grafting trials were inconclusive.
BARLEY AND VETCH YIELDS FROM DRYLAND ROTATIONS WITH VARYING TILLAGE AND RESIDUE MANAGEMENT UNDER MEDITERRANEAN CONDITIONS
Authors: PALA M. , RYAN J. , DIEKMANN J. , SINGH M. 
Published: October 2008

SUMMARYWith increasing land-use pressure in semi-arid, dryland Middle Eastern agriculture, fallow-based cereal production has given way to cropping intensification, including legume-based rotations along with conservation tillage and on-farm straw disposal. Such agronomic developments can only be biologically and economically assessed in multi-year trials. Thus, this 10-year study examined the influence of tillage systems (conventional and shallow or conservation) and variable stubble management, including compost application, on yields of barley and vetch grown in rotation. Barley yielded higher with compost applied every two or four years than with burning or soil-incorporating the straw and stubble. Barley straw and grain yields were generally higher with the mouldboard plough. Similarly with vetch, treatments involving compost application yielded significantly higher than burning or incorporating the straw and stubble. Despite yearly differences between crop yields, the pattern of treatment differences was consistent. Thus, the cereal–vetch rotation system is sustainable, while excess straw could be used as compost with benefit to the crop. Though there was no clear advantage of the shallow conservation-type tillage, the energy costs are less, thus indicating its possible advantage over conventional deep tillage in such rotational cropping systems
Organic matter in space - An overview
Authors: van Dishoeck Ewine F. 
Published: October 2008

AbstractOrganic compounds are ubiquitous in space: they are found in diffuse clouds, in the envelopes of evolved stars, in dense star-forming regions, in protoplanetary disks, in comets, on the surfaces of minor planets, and in meteorites and interplanetary dust particles. This brief overview summarizes the observational evidence for the types of organics found in these regions, with emphasis on recent developments. The Stardust sample-return mission provides the first opportunity to study primitive cometary material with sophisticated equipment on Earth. Similarities and differences between the types of compounds in different regions are discussed in the context of the processes that can modify them. The importance of laboratory astrophysics is emphasized.