bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Drain Spacing and Phosphorus Levels on Yield, Chemical Composition and Uptake of Nutrients by Indian Mustard (Brassica juncea)
Authors: Singh K. N. , Swarup Anand , Sharma D. P. , Rao K. V. G. K.
Published: October 2008

Field experiments during the winter seasons of 1986–7 and 1987–8 studied the effect of three sub-surface drain spacings and three levels of phosphorus on the yield, chemical composition and uptake of nutrients by Indian mustard (Brassica juncea). The number of siliquae m-2and seed yield decreased with increasing drain spacing. Application of phosphorus increased seed yield and yield attributes. The concentrations of nitrogen, phosphorus and potassium in the seed and stalks decreased and those of sodium, calcium and magnesium increased with increasing drain spacing, but application of phosphorus increased the concentration of these nutrients in the seed and stalks. Absence of phosphorus in the drain water effluent and the level of available phosphorus in the soil profile after crop harvest indicated very slow movement of phosphorus, most of which was retained in the top 30 cm of soil.
Yield Stability of Cassava During Prolonged Mid-Season Water Stress
Authors: El-Sharkawy Mabrouk A. , Hernández Anna Del Pilar , Hershey Clair
Published: October 2008

Yield stability in cassava requires genotypes that produce well under the variable moisture conditions encountered during the growth cycle. Plant characteristics related to yield stability were studied in two cassava clones subjected to 105 days of water stress in a field drainage lysimeter. Stress conditions commenced 117 days after planting, and the plants were allowed to recover at the end of the stress period for the rest of the growth cycle. Water stress restricted the growth of leaves and stems, but root yields were increased or remained unaffected. Leaf water potential varied little with stress, but gas exchange rates were about 75% those of the control throughout the stress period in both cultivars. Under stress, the plants partially closed their stomata and extracted deep soil moisture slowly. A high yield in both wet and stressed environments was associated with high mean LAI, better leaf retention, and greater partitioning of shoot biomass into leaf formation.
Evaluation of the Leaf of a Range of Tree Legumes as a Source of Nitrogen for Crop Growth
Authors: Gutteridge R. C.
Published: October 2008

The leaf mulch of the tree legumes Acacia cunninghamii, A. fimbriata, Calliandra calothyrsus, Gliricidia sepium, Leucaena leucocephala and Sesbania sesban was evaluated as a source of nitrogen for maize growth in glasshouse pot experiments. The mulch of Sesbania sesban resulted in the largest yields of maize stover but yields were less than those that resulted from application of equivalent rates of fertilizer nitrogen. The mulches of Gliricidia and Leucaena also produced a yield response in maize but those of Calliandra and the two Acacia species were ineffective as sources of nitrogen in the short term. Sesbania mulch at the equivalent of 5 t dry matter ha-1 produced a maize yield similar to that obtained with 75 kg N ha-1. The poor response to Calliandra and Acacia mulch may be associated with the high polyphenol and/or lignin content of the leaf of these species.
A Case for On-farm Trials of Fodder Banks on the Adamawa Plateau in Cameroon
Authors: Tarawali G. , Pamo E. T.
Published: October 2008

The poor quality of the natural vegetation in the dry season affects both animal productivity and the lives of the pastoral community in the Adamawa Plateau of Cameroon but may be improved by introduction of the forage legume Stylosanthes guianensis. When used in a ‘fodder bank’ system, Stylosanthes grew to an average plant height of 1.41 m, had a dry matter productivity of 5.5 t ha−1 and comprised 93.4% of the pasture's botanical composition at the end of the growing season, indicating that fodder banks have considerable potential to enhance animal and crop production in Cameroon. Complementary studies conducted in Nigeria on the yield benefits of cropping leguminous pastures support the feasibility of using fodder banks as a means of improving the livelihoods of small scale farmers.
Phosphorus Utilization Efficiency as Affected by Component Population, Rhizobial Inoculation and Applied Nitrogen in Maize/Mungbean Intercropping
Authors: Chowdhury Mrinal K. , Rosario Elpidio L.
Published: October 2008

The effects of component population, rhizobial inoculation and applied nitrogen on the efficiency of phosphorus utilization in maize/mungbean intercropping were examined in two experiments. The efficiency of phosphorus absorption decreased by between 5 and 43% in maize and by between 31 and 58% in mungbean as a result of intercropping. The overall efficiency of phosphorus absorption in intercropping decreased with increasing nitrogen level but a parallel increase in overall conversion efficiency maintained a constant and large land equivalent ratio (LER) up to the highest level of nitrogen. The increase in LER over unity, however, was due primarily to the greater total absorption of phosphorus by maize and mungbean together in intercropping compared with that when they were grown in pure stands.
Effects of Foliar Micronutrient Fertilizers on the Yield of Irrigated Cotton on the Vertisols of the Sudan Gezira
Authors: Ishag H. M.
Published: October 2008

Field experiments were conducted on very alkaline calcareous soils to investigate the effects of two proprietary foliar micronutrient fertilizers, Wuxal Suspension Polymicro and Bayfolan 11-8-6, containing iron, zinc, manganese and boron, on the seed cotton yield of Gossypium barbadense and G. hirsutum. Two applications of foliar fertilizer, one at flowering and one three weeks after flowering, increased yield by 40–68%. The foliar fertilizers enhanced earliness and minimized nutrient depletion from the leaves, and thus increased reproductive efficiency.
Analysis of On-farm Rice Yield Data from India
Authors: Simmonds N. W. , Talbot M.
Published: October 2008

Data recently published in this journal on grain yields of new rice varieties, grown under rainfed conditions on-farm in two villages in Uttar Pradesh, were analysed. The new varieties were spectacularly better than the landraces with which they were compared and showed a high regression slope (>2) against the landraces. If supported by further studies, such experiments could provide an appropriate, but hitherto unexplored, approach to plant breeding for poor, small farmers operating with low inputs.
Comparison of Oilseed Crops with Wheat and Barley in a Dry Mediterranean Climate
Authors: Hadjichristodoulou A.
Published: October 2008

The best available varieties of barley, durum wheat, rapeseed, safflower and sunflower were compared for their yield of grain and oil and other traits under rainfed conditions and with supplementary irrigation in the relatively dry Mediterranean climate of Cyprus. The grain yields of the oilseed crops safflower and rapeseed when grown under conditions of plentiful rainfall or with supplementary irrigation were 3–5 t ha−l. Considering the high prices of oilseeds on the world market, the income from oil crops compares favourably with that from barley and wheat. However, under conditions of limited rainfall (300 mm) and without supplementary irrigation the yields of oilseed crops were extremely poor, at the most 0.6 t ha−1. Grain and oil yields of irrigated safflower and rapeseed were larger than those of sunflower. Among the oilseed crops, sunflower received most irrigation water and rapeseed the least. Under rainfed conditions, with precipitation less than 300 mm, cereals were the only successful crops. It is concluded that in the high rainfall areas of West Asia and North Africa, or with supplementary irrigation, including treated municipal wastewater, oilseed crops can be successfully grown.
Production Possibility Frontiers and Estimation of Competition Effects: The Use ofA PrioriInformation on Biological Processes in Intercropping
Authors: Ranganathan Radha
Published: October 2008

Production possibility frontiers contribute much to an economic evaluation of yield advantages from intercropping. The difficulty with estimating a production frontier empirically from experimental data is one of ascertaining that the fitted curve corresponds with the frontier. This problem has been overcome by deriving the frontier froma prioriknowledge of the biological processes that determine the outcome in intercropping. The hyperbolic relationship between biomass yield and plant density, and the parameters that characterize the degree of intra-and inter-specific competition in intercropping are used in this paper to derive production possibility frontiers. The method is illustrated with data from three intercropping studies. A brief review of the two main methods used by researchers to evaluate the results of intercropping, and their limitations, is also presented.
Use of Tine-tillage, with Atrazine Weed Control, to Permit Earlier Planting of Maize by Smallholder Farmers in Zimbabwe
Authors: Shumba E. M. , Waddington S. R. , Rukuni M
Published: October 2008

Because of shortages of oxen for mouldboard ploughing, delayed planting of maize is common in Mangwende, Zimbabwe and reduces grain yield by 32%. On-farm experiments over four years tested the possibility of using a ripper tine, with atrazine herbicide, to allow smallholders to plant maize earlier. Compared to mouldboard ploughing, tine cultivation increased grain yield at 13 out of 18 sites. All these sites had less than 240 mm of rainfall in January (which coincided with crop anthesis) and long term rainfall records suggest tine cultivation should raise yields in two out of three years. Handweeding and atrazine treatments gave similar grain yields when used with tine cultivation, provided weeds were controlled within 14 days of crop emergence. Tine cultivation was economic at sites where the yield was greater than that with the mouldboard plough. The farmers could manage the combination of tine and atrazine use on a field scale.
Adaptation of Lentil to the Mediterranean Environment. I. Factors Affecting Yield Under Drought Conditions
Authors: Silim S. N. , Saxena M. C. , Erskine W.
Published: October 2008

Lentil frequently suffers from drought stress towards the end of the growing season in rainfed Mediterranean farming systems. This study aimed to quantify the contribution of yield potential under irrigated conditions and of drought escape to the adaptation of lentils to drought, and to identify traits of value in selection for adaptation to a rain-fed Mediterranean environment. Twenty-five diverse lentil lines were sown under both irrigated and rainfed conditions in the 1987/88 and 1988/89 seasons in northern Syria. In 1987/88 the total seasonal rainfall was 403 mm and average rainfed biomass and seed yields were 5.0 and 1.8 t ha-l, respectively. In contrast, in 1988/89 the total season rainfall was 180 mm and average biomass and seed yields were only 0.67 and 0.12 t ha-1, respectively. Early vigour (estimated as a visual score) and percentage ground cover were strongly associated with final biomass, and were of value in predicting economic yield (seed + straw). Early maturity was correlated with seed yield. In the dry season 1988/89, 49% of the variation in seed yield among lines was accounted for by variation in flowering time. Drought escape was clearly the key response to drought. For severely drought-prone areas, selection for early flowering is therefore required. Variation in flowering time and seed yield under irrigated conditions accounted for 62% of seed yield variation under drought stress.
Adaptation of Lentil to the Mediterranean Environment. II. Response to Moisture Supply
Authors: Silim S. N. , Saxena M. C. , Erskine W.
Published: October 2008

Lentil is generally grown as a rainfed crop in areas of West Asia and North Africa where rainfall is highly variable. This study aimed to measure genetic responses to variation in moisture supply in the yield of seed and straw, evapotranspiration and water use efficiency, to guide the lentil breeding programme. The response of 25 diverse lentil lines to a soil water gradient was studied in 1987/88 and 1988/89 at Breda, northern Syria, using a line-source sprinkler system. The coefficient of determination between rainfed and irrigated seed yield in the dry 1988/89 season was r2 = 0.26, and the genotypes that were well adapted to dry conditions were different from those well adapted to wet conditions. However, there were also widely adapted genotypes that yielded well under both wet and dry conditions. The selection of such genotypes might be appropriate for the region receiving 300–400 mm annual rainfall, in contrast with the approach to selection suggested for drier areas (less than 300 mm annual rainfall) in a companion article. Soil moisture extraction from the time of maximum profile recharge to maturity in 1987/88 and cumulative crop evapotranspiration in the 1987/88 rainfed crop did not differ among lentil lines. In the irrigated treatment, however, evapotranspiration in the medium to late maturing lines exceeded that in the early maturing lines towards maturity.
The Impact of Varying Levels of Competition from Pearl Millet on the Yields of Groundnut Cultivars
Authors: Ndunguru B. J. , Williams J. H.
Published: October 2008

A series of trials investigated the response of a range of groundnut genotypes to varied levels of competition from millet in intercrop situations in both the Sahelian and Sudanian agro-climatic zones. No genotype interactions were observed in response to different millet population levels. Introducing millet into groundnut cultivation provided considerable benefits to the farmer, particularly at the less dense millet populations, but the introduction of groundnut into millet cropping consistently reduced the yield of millet, with little gain in groundnut yields.
Collecting Meaningful Data on Labour Use in On-Farm Trials in Sub-Saharan Africa
Authors: Spencer Dunstan S. C.
Published: October 2008

In order to measure the effects of new agricultural technologies on labour productivity in sub-Saharan Africa, on-farm trials are usually conducted using small plots. Farmers who keep no records have to be interviewed frequently to minimize the effect of memory loss on the accuracy of the data collected. In this paper, results are reported of experiments in the forest zone of Nigeria and the semi-arid Sahel of Niger. They show that if researchers can take steps to fix events in the memory of farmers, accurate labour use data can be collected in interviews as long as three months after the events being recalled. A range of plot sizes, with a minimum of 350 m2 in the forest zone, needs to be used to measure accurately labour use per hectare and to take into account the effect of economies of size on crop production.

Recopilacón de datos significatiaos sobre el use de mano de obra en estudios realizados en fincas del sub-Sahara africano
Effect of Heat and Drought Stress on Sorghum (Sorghum Bicolor). I. Panicle Development and Leaf Appearance
Authors: Craufurd P. Q. , Flower D. J. , Peacock J. M.
Published: October 2008

Seven sorghum lines, flowering from 50 to 87 days after sowing, were subjected to early drought stress, late stress, and both early and late stress in the field during the dry season in India. Panicle initiation was delayed by 2–25 days and flowering by 1–59 days by the drought stress treatments, the greatest effect being in the treatment subjected to both early and late stress. Stress increased the period between panicle initiation and flowering by retarding the rate of panicle development; when stress was severe panicle development stopped. Upon relief of stress following irrigation, panicle development resumed at rates comparable to those in a fully irrigated control. The rate of leaf appearance was affected in a similar manner to panicle development soon after water was withheld. Rate of leaf appearance and panicle development decreased as pre-dawn leaf water potential decreased and ceased at water potentials of −0.55 and −0.7 MPa, respectively.
Effect of Heat and Drought Stress on Sorghum (Sorghum Bicolor). II. Grain Yield
Authors: Craufurd P. Q. , Peacock J. M.
Published: October 2008

Three early and four later flowering lines of sorghum were subjected to three drought stress treatments (early, late and early plus late stress) in the field during the dry season at Hyderabad in India. Mean diurnal temperature and evaporation rate were uniformly high throughout the experiment. The late and early plus late stress conditions were severe, while the early stress was mild.

Grain yield was affected by both the timing and the severity of the stress. The largest reduction (87%) in grain yield resulted from stress imposed during booting and flowering (late stress) in the early flowering lines; the same stress treatment on vegetative plants had no effect on grain yield. Increasing the duration of severe stress on vegetative plants (early plus late stress) reduced grain yield by 50–60%.

Grain yield was strongly and positively correlated with the number of grains m-2. Variation in grain yield was associated with variation in total dry matter rather than with harvest index, which was only reduced when stress occurred at flowering. Treatment effects on thermal growth rates (g m-2 °Cd-1) during the phase from booting to flowering confirmed that growth during this phase is the major determinant of yield potential (number of grains). The importance of phonology in research into drought resistance is discussed.
Methods of Identifying Genetic Diversity in Gliricidia Species for Biomass Production
Authors: Chamberlain J. R. , Galwey N. W.
Published: October 2008

Gliricidia sepium is a leguminous tree native to Mexico and Central America, and is utilized for fuelwood, animal fodder and green manure in rural communities. It is widely distributed throughout the tropics, but many populations of the tree have arisen from haphazard introductions of unknown quality. Methods for determining the genetic structure and origin of populations are therefore required as a basis for genetic improvement. In order to test the effectiveness of various measures of genetic diversity, provenances of G. sepium from Panama, Guatemala, Mexico and Honduras were studied by electrophoresis of seed storage proteins and the enzymes leucine aminopeptidase (LAP) and acid phosphatase (ACP), and by measurement of plant morphological characteristics. Study of seed storage proteins and morphological characters was very informative, and there was some genetic variation for ACP, but LAP showed no clear variation. In the cases where genetic variation was present, the different methods of study showed a consistent pattern of variation: genetic diversity was greatest in the population from Honduras, and least in that from Panama. This was contrary to expectations on the basis of the locations of origin of the populations and the range in which G. sepium is believed to be native. Electrophoresis of the storage proteins of Gliricidia maculata confirmed the status of this species as a distinct taxon.
Late Planting Effects on Early Versus Late Pearl Millet Genotypes in Niger
Authors: Reddy K. C. , Visser P. L.
Published: October 2008

The performance of two contrasting pearl millet (Pennisetum glaucum) genotypes was compared following five planting dates under rainfed conditions in deep sandy soils at Bengou, Niger in 1986 and 1987. The early and partially photo-sensitive cultivar HKB yielded more grain than the late and photo-sensitive cultivar Somno when planted with the first two seasonal rains. But after delayed planting, the crop growth rate and harvest index of cultivar HKB were reduced, leading to smaller grain yields even though the growth period, rainfall, radiation and temperature were similar at all the planting dates. In contrast, cultivar Somno maintained a small but stable harvest index over various planting dates, so that although its growth period and crop growth rate were reduced by delayed planting, the reduction in grain yield was less. Since agronomic manipulation, such as increased plant density and fertilizer application, can be used to increase crop growth rate, photo-sensitive millet genotypes such as cultivar Somno could be used for late July plantings in the Sudano-Sahelian zone.
Lodging in Lentil as Affected by Plant Population, Soil Moisture and Genotype
Authors: Ibrahim M. , Erskine W. , Hanti G. , Fares A.
Published: October 2008

The effects of levels of soil moisture and plant population on lodging and associated losses from mechanical harvesting of two lentil genotypes, one susceptible and one resistant to lodging, were investigated during 1986–87 and 1987–88 at Tel Hadya in northern Syria. High plant population increased lodging because the crowded plants had thin stems, while high levels of soil moisture caused lodging because biological yield was increased. When biological yields were high a two tonne increase in biological yield led to a one point increase in lodging score. Mechanical harvesting increased losses in biological yield due to lodging by 12% compared with yields obtained by hand harvesting under rainfed conditions and by 24% at the highest level ofsoil moisture. It is suggested that supplementary irrigation should be used in dry seasons in trials to select genotypes resistant to lodging.

Decaimiento de la lenteja
Adaptation of Extra Short Duration Pigeonpea to Rainfed Semi-Arid Environments
Authors: Chauhan Y. S. , Johansen C. , Singh Laxman
Published: October 2008

The adaptation of extra short duration (ESD) pigeonpea (Cajanus cajan) genotypes to rainfed environments was studied on Alfisols and Vertisols at the ICRISAT Center between 1987 and 1989. Despite a slightly shorter crop duration, the grain yield of ESD genotypes was twice as large on Alfisols as on Vertisols. On both soil types, the rate of growth and grain yield were better in crops sown on time than in those where sowing was delayed. The population levels necessary to maximize yield varied among genotypes on Alfisols, where the grain yield of several ESD genotypes compared favourably with that of ICPL 87, a standard short duration genotype. However, none of the ESD genotypes yielded more than ICPL 87 on the Vertisols.
Towards the Reliable Prediction of Time to Flowering in Six Annual Crops. II. Soyabean (Glycine Max)
Authors: Summerfield R. J. , Lawn R. J. , QI A. , Ellis R. H. , Roberts E. H. , Chay P. M. , Brouwer J. B. , Rose J. L. , Shanmugasundaram S. , Yeates S. J. , Sandover S.
Published: October 2008

Eleven genotypes of soyabean (Glycine max) of tropical, sub-tropical and temperate origin and one accession ofG. sojawere grown in six locations in Australia during 1986–88, and at one location in Australia and two in Taiwan during 1989–91. Dates of sowing were varied within and among locations so as to expose plants to as many as 32 environments of widely different diurnal temperature and daylength. Times from sowing to flowering (f) were recorded, from which rates of progress towards flowering (1/f) were calculated. These derived data were then related to mean pre-flowering values of temperature (T¯) and photoperiod (P) using a three-plane linear model developed from controlled environment data. Among genotypes, mean values offvaried between 24–49 d and between 139–291 d in the most- and least-inductive environments, respectively. These differences were associated with variations in P from about 11 to 16 h d-1, in daily mean maximum temperatures from about 17° to 36°C, in daily mean minimum temperatures from about 5° to 25°C, and in T¯ from about 11° to 30°C, that is, a very wide range of photothermal regimes. The relations of 1/fto T¯ and P can be described in photoperiod-insensitive genotypes by a thermal plane defined by two constants,aandb, and additionally by a photothermal plane defined by three constants, a′, b′ and c′, in the more numerous photoperiod-sensitive genotypes. If photoperiod-sensitive genotypes are grown in sufficiently long days then a third photoperiod and temperature-insensitive plane is exposed, defined by a constant, d′; this plane indicates the maximum delay in flowering of which the genotype is capable. The constants a′, b′, c′ and d′ define the delay in flowering caused by photoperiod-sensitivity genes. The two intercepts between the three planes define, respectively, the critical photoperiod, Pc, above which increase in daylength delays flowering, and the ceiling photoperiod, Pcc, above which there is no further delay. The values of the six constants for any genotype can be estimated from observations of fin several natural environments. Comparisons between years in Australia and between Australia and Taiwan show that these genotypic constants can predict 1/f, and so the time taken to flower, given data on latitude, sowing date and daily values of maximum and minimum air temperatures. This model is more accurate than an alternative logistic model; we also believe that all six constants in the three-plane rate model described here have biological meaning. They indicate separate genetic control of flowering responses to P and T¯ and could form a rational basis for the genetic characterization and analysis of these responses in the soyabean germplasm.

Pronóstico del momento de floración II
Comparison of Extra-Short-Duration Pigeonpea With Short-Season Legumes Under Rainfed Conditions on Alfisols
Authors: Nam N. H. , Chauhan Y. S. , Johansen C.
Published: October 2008

Extra-short-duration pigeonpea (Cajanus cajan) genotypes generally yielded more than short-season legumes when sown at the normal time on rainfed medium-deep Alfisols. However, their growth and yield were more reduced by delayed sowings and varied more widely between seasons than those of the short-season legumes, especially cowpea and black gram. All the crops gave lower yields on shallow Alfisols than on medium-deep Alfisols and none was consistently superior. Partitioning of dry matter into grain yield was less affected by time of sowing, soil and season in extra-short-duration pigeonpea genotypes than in short-season legumes. Less sensitivity of biomass accumulation to various abiotic constraints is therefore a major objective in improving the adaptation of extra-short-duration pigeonpea genotypes.

Cajanus cajan de duración extra-corta
Effects of Soil Moisture and Vapour Pressure Deficits on Shoot Growth and the Yield of Tea in the Kenya Highlands
Authors: Odhiambo H. O. , Nyabundi J. O. , Chweya J.
Published: October 2008

Prolonged moisture stress and high vapour pressure deficits reduced the shoot water potential, shoot population density, rate of shoot extension and yield of clonal tea. The more drought susceptible Clone 6/8 had a lower shoot water potential, rate of shoot extension, number of shoots per unit area, rate of shoot regeneration and yield than the more tolerant Clones 31/8, 57/15 and 15/10 during the periods of low soil moisture, which coincided with high vapour pressure deficits. The changes in the shoot growth components could be used as an index of the suitability of different clones for different regimes of soil moisture and vapour pressure deficits.

Factores ambientales que afectan el rendimiento del té
Effects of Intercropping Young Plants of the Compact Arabica Coffee Hybrid Cultivar Ruiru 11 with Potatoes, Tomatoes, Beans and Maize on Coffee Yields and Economic Returns in Kenya
Authors: Njoroge J. M. , Waithaka K. , Chweya J. A.
Published: October 2008

The effects of intercropping young plants of the compact arabica coffee hybrid cultivar Ruiru 11 with potatoes, tomatoes, maize and Phaseolus (dry) beans were studied between 1987 and 1989 at Ruiru in Kenya. Yields of clean (hulled) coffee were reduced by the maize intercrop by 59–100%. Coffee bean size, and raw, roast and liquor quality were not significantly affected by the potato, tomato and bean intercrops, which gave positive net economic benefits. Potatoes planted between all the coffee rows gave the largest marginal rate of economic return, followed by tomatoes in combination with beans. The technically and economically viable intercrops for coffee were potatoes, tomatoes, beans, and tomatoes in combination with beans.

Siembra simultánea de café Araébica y cultivos para la alimentatión
Optimizing Fertilizer Use and Practical Rainfall Capture in a Semi-Arid Environment with Variable Rainfall
Authors: Piha M. I.
Published: October 2008

Fertilizer use in the semi-arid tropics is considered risky because of the unreliable rainfall pattern. A flexible system of fertilization was devised which allowed for high yields in wet years, and reduced financial losses in dry years. Relatively immobile nutrients, such as phosphorus, potassium and sulphur, were applied at rates determined from generalized soil properties and the total nutrient uptake required for a crop to achieve its maximum yield potential in a season with average rainfall. Nitrogen was applied as a series of split applications, which were adjusted during the season according to the degree of water stress observed. This approach was tested in on-farm trials for maize production on nutrient-poor sandy soils in three regions of Zimbabwe, and resulted in larger yields and profits than current recommendations, providing an accept able level of financial return. Small further yield increases were possible, at acceptable returns, when these fertilizer practices were combined with the establishment of tied-ridges by ox-drawn implements, 30 days after planting. By careful estimation of yield potential, and appropriate adjustments to soil fertility, this system of soil management could be applied to other cropping situations and other areas with variable rainfall.

Uso de fertilizantes para condiciones de precitación variable
Responses of a Forage Hay Crop to the Residual Effects of Nitrogen and Phosphorus Fertilizers in On-Farm Trials in Northern Syria
Authors: Wahbi A. , Matar A. E. , Jones M. J.
Published: October 2008

Fourteen on-farm sites used in barley fertilizer trials were retained for a second year and, without further fertilizer, sown with a mixed vetch/barley forage crop. Rainfall at the sites ranged from 149 to 451 mm, and linear regression on rainfall accounted for 76% of the variation in hay yield between the sites, with a greater rain-related increase in vetch than barley. Soil nitrogen and phosphorus content at planting time in the second year was significantly affected by the rate of fertilizer application in the previous year. Previous phosphate fertilization tended to increase hay yields, particularly at sites where levels of native available phosphate were poor. However, responses to residual fertilizer nitrogen were small and variable.

Respuesta al N y P residual en el norte de Siria
Response of Seed Longevity to Moisture Content in Three Genotypes of Soyabean (GLYCINE MAX)
Authors: Zanakis G. N. , Ellis R. H. , Summerfield R. J.
Published: October 2008

Reports that an Indonesian soyabean (Glycine max) line (TGm737p) shows greater seed storage longevity than an American cultivar (Bossier), and that the cross between them (TG×536–02D) is intermediate between the two parents in this regard, were investigated by growing all three genotypes under identical conditions (30°C/20°C, 12 h d-1 photoperiod) in a plastics house. Seeds were harvested when moisture content had declined naturally to 14–15% (wet basis), and then stored hermetically at five different moisture contents at 40°C. Analyses of the resultant seed survival curves revealed that the seed lot constant Ki (a measure of potential longevity) was greatest in TGm737p and least in cv. Bossier, the cross being much closer to the American parent in this regard. The negative logarithmic relation between σ (standard deviation of the frequency distribution of seed deaths in time) and moisture content did not differ (p > 0.10) among the three genotypes. Moreover, this relation was close to that predicted by earlier results for four different genotypes. Similarly, there was no significant difference (p > 0.25) among genotypes in the negative semi-logarithmic relation between σ and seed equilibrium relative humidity (rh): the regression slope was equivalent to a doubling of longevity for each 8.0% reduction in rh. Finally, comparison of the negative logarithmic relation between absolute longevity (50% viability period) and seed moisture content confirmed that TGm737p showed greatest longevity (p > 0.005), but failed to show a difference in absolute longevity between cv. Bossier and the cross (p > 0.25). The results confirm that the seed viability equation of Ellis and Roberts (1980a, b) provides a framework within which the seed longevity of different genotypes can be compared. They suggest too that there is considerable doubt as to whether or not the greater potential longevity of the Indonesian line TGm737p has been incorporated successfully into the cross TG×536–02D.

Longevidad de la semilla de soja
Rethinking the Farmer's Role in Plant Breeding: Local Bean Experts and On-station Selection in Rwanda
Authors: Sperling Louise , Loevinsohn Michael E. , Ntabomvura Beatrice
Published: October 2008

Varietal selection is particularly difficult for very heterogeneous environments where farmers have a range of preferences. To address these issues in Rwanda, local bean experts, generally women, are invited to the research station to assess cultivars and to select those they prefer for their plots. Farmers use observed yield as only one of several criteria to predict varietal performance in their more stressed home environments. The varieties they choose are often higher yielding on-farm and are retained longer by farmers than those selected by the breeders. The results of early farmer involvement also compare favourably with those of the standard breeding programme in terms of enhanced genetic diversity and reduced research costs. There are few pre-conditions for developing such a client-driven breeding programme.

Papel del agricultor en la selección de variedades para una estación inaestigación
A Survey of the Mineral Nutrition of Valencia Orange in Trinidad
Authors: Weir C. C.
Published: October 2008

A survey of citrus groves was conducted by analysing leaf and soil samples from the main citrus growing areas of the island. The leaf data, evaluated by comparing them with the California leaf analysis standards for assessing the nutrient status of citrus leaves, indicated that the California standards are of limited value in attempting to assess the nutritional status of citrus in Trinidad, particularly with reference to the elements zinc and magnesium. The possibility of using soil analyses as an index to the mineral nutrition of citrus is worthy of consideration. Although symptoms of zinc and magnesium deficiencies had often been observed, these elements had not been given the attention they deserved in the regular fertilizer programmes.
Effects of Nitrogen, Phosphorus and Potassium on Flowering and Yield of Soybeans in Nigeria
Authors: Tewari G. P.
Published: October 2008

A NPK factorial experiment was conducted during two successive cropping seasons to study direct and residual effects of various treatments on the flower initiation and yield of soybeans. Plants were slower to reach the maximum flowering stage in the year of fertilizer application than in the following year. During the first year potassium in association with phosphorus delayed the flower forming process, whereas potassium alone hastened flowering in the second year unless associated with a high dosage of nitrogen. All the treatments gave far greater yields in the first season, suggesting that fertilizers should be applied during every cropping season. Nitrogen and phosphorus at 20 pounds of N2 and P2O5, per acre gave the biggest yields, but potassium failed to show any response. The residual responses to potassium and phosphorus during the second year were significant but not to nitrogen.
Resistance to Bacterial Blight of Cotton: The Genes B9 and B10
Authors: Innes N. L.
Published: October 2008

Lagière's B9 from Allen 51–296 (Gossypium hirsutum) was found to be non-homologous with Knight's B genes B1–B7, B9 and Bherb. To differentiate between this gene and Knight's B9 from G. herbaceum the symbols have been changed to B9L and B9K respectively. It was impossible to test Knight's B10 from Kufra Oasis G. punctatum and Lagière's B10 from Allen 51–296, but to avoid confusion it is proposed that these genes should be known as B10K and B10L.
Responses of Sugar Cane to Sunn Green Manuring in India
Authors: Singh Ambika
Published: October 2008

The results are reported of three field experiments conducted from 1955 to 1963 to investigate the effects of sunn green manuring in the sugar cane rotation. In a three-year rotation with sugar cane and wheat, green manuring twice was not superior to green manuring once, either in terms of sugar cane yield or the nitrogen and organic carbon status of the soil. Two experiments showed that the yield increase of cane was proportional to the weight of the green manure crop, irrespective of how the latter was disposed of, suggesting that the only factor with which yield increase was correlated was the weight of roots of sunn which were incorporated into the soil. The green manure effect is resolved into two components namely ‘green matter effect’ and ‘legume effect’, both of which are additive and nearly equal.
Agronomic Use of a Soil Survey in Barbados
Authors: Hudson J. C.
Published: October 2008

A detailed soil map of the Island of Barbados has recently been completed, and a number of factors make this area an interesting ‘laboratory‘ in which to investigate the uses to which such a map may be put. The map has already proved to be of considerable value in extension work by providing a more rational basis for advice about cultivations, growth and ripening patterns, crop diversification and the organization of simple dispersed-block trials. Because of the importance of available soil moisture and drainage, techniques have been developed to investigate these aspects in relation to the different soil types. The most rewarding feature, however, has been the enthusiastic response of plantation managers to the soil map as a basis for the exchange of information, the communication of the results of experimental work, the reorganization of field boundaries, and the introduction of new crops.
Groundnut Improvement in the Sudan
Authors: Tahir W. M.
Published: October 2008

Groundnuts (Arachis hypogaea L.) have been found to be one of the most promising additional cash crops for diversifying Sudan agriculture. Three hundred and thirteen agronomically distinct forms have been separated from 171 varietal samples, and 121 short-maturing upright bunch types and 49 long-maturing spreading bunch types have been tested in a series of trials over several years in four climatic regions. Among upright bunch varieties, PJ121070 and Large Natal 142 appeared to be the best selections as oil and confectionery types respectively, and among spreading bunch varieties, MH.372, Beladi Bunch and NJ37 for oil, confectionery kernels and unshelled nuts respectively. A hybridization programme was started in 1959 to improve the existing varieties of groundnuts and to produce non-germinating upright bunch varieties for growing in the heavy clay soils. Inheritance studies indicated the dominance of an alternate pattern of branching, prostrate plant habit and long maturity. Dominance of testa colours was in the order of purple–red–russet brown–light brown–white. Recessive albino seedlings were observed only in crosses involving different branching pattern. There appeared to be no association between the various characters studied except maturity period, which was related to branching pattern and growth habit.
Control of Leaf-Cutting Ants (Atta Spp.) by Fogging
Authors: Kennard C. P.
Published: October 2008

In a trial carried out in 1958, aldrin applied as a fog with a swingfog machine at concentrations of 10 and 20 per cent in gas oil was more effective than dieldrin or chlordane at similar concentrations for control of Atta cephalotes. Two applications of 10 and 20 per cent benzene hexachloride and toxaphene failed to give complete control. In a subsequent trial, aldrin in concentrations ranging from 2·5 to 8·0 per cent was also found to be effective against A. cephalotes but against A. laevigata, aldrin and dieldrin were more effective than chlordane at concentrations of 5·0 and 2·5 per cent. In campaigns carried out from 1959 to 1963, 5000 nests were destroyed by fogging with 2·5 per cent aldrin in gas oil.
Effects of Planting Dates on Flowering and Yields of Cowpeas in Nigeria
Authors: Tewari G. P.
Published: October 2008

A two-year field experiment was conducted with fifteen varieties of cowpeas to evaluate responses to three different planting dates in relation to flowering and yield of beans. It appeared that most of the cowpea varieties required a day length of more than 12 hours to initiate flower formation. During both years 1962 and 1963, May plantings gave the best results, and July, August and September plantings failed to form flowers.
Availability of Phosphorus to Sugar Cane in Hawaii as Influenced by Various Phosphorus Fertilizers and Methods of Application
Authors: de Datta S. K. , Moomaw J. C.
Published: October 2008

An experiment was carried out in the glasshouse to determine the availability of P, and utilization of added phosphate fertilizers from three fertilizer materials, applied by two different methods to sugar cane grown in four diverse soil systems. Phosphorus was applied at the equivalent rate of 175 pounds P (400 pounds P2O5) per acre. A larger response from added P in terms of plant yields was obtained from an aluminous ferruginous latosol and least from dark magnesium clay. Differences in yields of sugar cane were evidently associated with differences in P content in the cane plants and, in certain cases, with a reduction in Al content in plant tops, and the less soluble superphosphate increased yields more than the highly soluble NH4H2PO4. Phosphate fertilizers applied as foliar spray greatly increased the P content in the plants, and plants contained twenty times more P when sprayed with NH4H2PO4 than when the same fertilizer was applied to the soil. However, increased P content in the plants did not necessarily indicate that the P was translocated within the plants or that the added P participated in metabolic processes. The evidence indicated that in soils where the ‘A’ value was high the P status of the sugar cane tops was not correspondingly high.
Effects of Crop Height on Evaporation from Lucerne and Wheat Grown in Lysimeters under Advective Conditions in the Sudan
Authors: El Nadi A. H. , Hudson J. P.
Published: October 2008

A simple but reliable type of drainage lysimeter was used to measure evaporation rates from lucerne and wheat and these were compared with calculated estimates of evaporation. Plant height was found to have an important effect on the amount of water lost from a plant cover, which also varied between two different species of crop of similar heights. Using two different soil types, maintained at a high moisture status, the rate of water loss was not influenced by the type of soil in which the plants were grown.
Fertilizer Placement for Sole-Crop Cowpeas in Southern Nigeria
Authors: Ezedinma F. O. C.
Published: October 2008

The time and method of placement, and the distance from the plant at which fertilizers should be placed, was studied on sole-crop cowpeas. The development and yield of both early and late season crops were highest where fertilizers were applied at planting. It is suggested that it might be more advantageous to plough the fertilizers under before planting, so that the nutrients will become available to the seedlings from the time they emerge. Application of fertilizer in two bands gave the highest yields, but was not significantly superior to a less laborious method of application in one band. The distance at which the fertilizer was placed, and treatment interactions, did not show any definite trends.
Effect of Planting Time on Yield and Quality of Flue-Cured Tobacco in Iringa District, Tanzania
Authors: Akehurst B. C.
Published: October 2008

As part of a project to introduce Virginian-type flue-cured tobacco varieties into a new area, a number of experiments on the effect of time of planting showed that returns declined according to the delay in planting after the start of the rains. This decline was not arrested by differential fertilization, soil fumigation or the use of quicker maturing varieties. The early plantings appeared to have a greater growth potential, which could often be more fully realised under improved cultural techniques. Thus, early plantings gave substantial positive responses to applications of nitrogen which had little effect on, or were detrimental to, later plantings. It is suggested that the responses noted were linked with weather conditions during the first few weeks after planting. The drier and more sunny these were, the better, and the possibility therefore arises of using rainfall probability data, with a minimum of field experimentation, in future problems of this nature.
Responses of Rhodes Grass and Overseeded Legumes to Nitrogen and Potash Fertilizers and to the Availability of Soil Potassium in Israel
Authors: Dovrat A.
Published: October 2008

Results are reported from experiments with nitrogen and potash fertilizers in irrigated Rhodes grass (Chloris gayana), into which annual winter legumes, e.g. berseem (Trifolium alexandrinum) and vetch (Vicia sativa) were overseeded. The experiments were carried out over a three year period on a sandy loam soil at Bet Dagan Experimental Farm, Israel. Ammonium sulphate, applied in equal split rates of up to 384 lb N per acre, linearly increased dry matter yields of Rhodes grass, and the increase of yield proportionally increased the uptake of K by harvest. The K content of the dry matter decreased with increasing nitrogen fertilization to 0·47 per cent which, however, was still found sufficient for maintaining maximum production of Rhodes grass. The yield of annual winter legumes decreased proportionally to the amount of nitrogen fertilizer applied during the summer. Acute potassium starvation was observed. An autumn application of potassium chloride restored dry matter production to normal levels. Availability of soil K, expressed in terms of energies of replacement [ΔF(− 1)], decreased proportionally to the amount of nitrogen fertilizer applied. When ΔF reached approximately 4,250 cal/mol, overseeded legumes were K-deficient, whereas Rhodes grass at that value was still able to extinct sufficient K from the soil for normal growth.
Improvement of Permanent Pasture by Overdrilling and Oversowing I. Pasture Establishment by Overdrilling
Authors: Warboys I. B. , Johnson R. J.
Published: October 2008

The apparent success of overdrilling in improving poor grazing pasture in other temperate climates led to an investigation of the technique under British conditions. With the development of a suitable machine, both for controlling competition and for drilling seeds and fertilizers simultaneously into established pasture, field trials were initiated in 1961 and 1962. Despite the achievement of satisfactory furrows for germination, the subsequent emergence and establishment of improved grasses and white clover was poor. This was thought to be due to various factors, particularly to competition from the short vigorous lowland swards, but also to unsatisfactory furrow environments where difficulties were experienced in covering seeds adequately, and in protecting seedlings from desiccation. Even when an overall application of herbicide was used to control competition, the seedlings were slow to colonize the bare ground and appeared to be particularly vulnerable to desiccation where vegetation was absent. Under the conditions of sward and climate at Aberystwyth, overdrilling by itself appears to offer no promise as a means of grassland improvement.