bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Frequent Clipping on Three Perennial Weeds, Cynodon dactylon (L.) Pers., Sorghum halepense (L.) Pers. and Cyperus rotundus L.
Authors: Horowitz Menashe
Published: October 2008

Established plants of bermudagrass (Cynodon dactylon (L.) Pers.), johnsongrass (Sorghum halepense (L.) Pers.) and purple nutsedge (Cyperus rotundus L.), grown in containers, were repeatedly clipped to the ground from spring to winter, at monthly and bi-weekly intervals. Regrowth of bermudagrass was markedly reduced after monthly clippings, but all plants regrew in the following March; there was no regeneration in March of bi-weekly clipped plants. Severe decrease of regrowth of clipped johnsongrass occurred after bi-weekly or monthly clippings, but a quarter of the clipped plants regenerated in the following March. Nutsedge was more resistant to clipping than the other two species and all clipped plants regrew vigorously in the following March. Repeated clipping reduced the rhizome length or tuber number and the dry matter content in the regrown plants in proportion to the frequency of clipping.
Iron Chlorosis in Peanuts on a Calcareous Jordan Valley Soil
Authors: Lachover D. , Ebercon Adeline
Published: October 2008

A pot experiment was carried out to study various aspects of growing peanuts in highly calcareous soil, with special reference to iron chlorosis. There was good agreement among the criteria used to evaluate the need for iron and the effectiveness of different chelates or methods of application (i.e. visual symptoms, chemical diagnosis and yield response). Of the iron chelates tested, Sequestrene 138 proved the most effective. Promising results were also obtained by coating seeds with chelate as an iron starter, followed by an additional top dressing. The results indicate the possibility of growing peanut economically in the highly calcareous soil tested using iron chelate —Fe EDDHA (Sequestrene 138).
Chemical Control of Powdery Mildews of Cucumber and Okra in the Sudan
Authors: Omer M. E. H.
Published: October 2008

The effect of fungicides on the development of powdery mildews on cucumber and okra was studied. Most of the chemicals tested controlled the disease and significantly increased yields, though a dimethirimol-resistant Oidium sp. appeared on okra. Seed dressing with the systemic fungicides thiophanate and benomyl conferred resistance to the disease for a few days whereas soil application gave protection for more than eleven weeks.
Studies on White Yam (Dioscorea rotundata) III. Foliar Analysis for Nitrogen Nutrition
Authors: Sobulo R. A.
Published: October 2008

The concentrations of total nitrogen and nitrate–nitrogen in yam leaves receiving various levels of nitrogen were determined fortnightly. Nitrate–nitrogen was superior to total nitrogen as an index of nitrogen nutrition. Correlation coefficients between nitrate–nitrogen at various sampling dates and rate of nitrogen application were highest between late June and early July in two seasons, indicating that this is the best time to take single samples for foliar analysis. A relation was demonstrated between nitrate–nitrogen at this period and tuber yield.
Genotype–Environment Interactions and their Application in a Maize Breeding Programme
Authors: Abington J. B.
Published: October 2008

The problems resulting from genotype × environment interactions are discussed, giving an example where the application of statistical techniques to maize breeding makes it possible to assess the effects of such interactions. A method of maize breeding is proposed which enables a number of objectives to be achieved from a single breeding programme.
Border Effects in Rice Experimental Plots. II. Varietal Competition
Authors: Gomez Kwanchai A.
Published: October 2008

Three varieties of rice, selected for their differences in height and tillering ability, were grown side by side in 10-row plots to determine the effect of varietal competition on plot yields. Plants in border rows performed differently from those in the centres of plots, higher-tillering or taller varieties tending to depress the performance of adjacent plants. Comparisons among varieties based on plot yields, determined with and without excluding the border rows, gave different results. Excluding two rows on each side of a plot was sufficient to eliminate the effects of varietal competition on yield data.
Principles for Using Fertilizers to Improve Red Ferrallitic Soils in Uganda
Authors: Jones E.
Published: October 2008

The decline in fertility of red ferrallitic soils in Uganda under arable cropping, and its restoration under permanent vegetation, is shown to be associated with losses and gains of major nutrients by the top-soil. A fertilizer mixture formulated to correct the losses and imitate the gains of nutrients consistently increased crop yields and maintained soil fertility over 4 years. Reasons for the success of the fertilizer mixture and its potential use in other tropical areas are discussed.
Effects of Weed Competition, Defoliation and Time of Harvest of Soyabeans
Authors: Hammerton John L.
Published: October 2008

Controlling weeds until 6 weeks after crop emergence gave a yield of soyabeans only 85 per cent that of the clean-weeded control treatment. Delaying weeding until 3 or 6 weeks after emergence gave yields 89 per cent and 69 per cent respectively of the control. Narrow crop rows (30.5 cm.) gave higher yields than wide rows (61 cm.). Defoliation of soyabeans reduced pod number, seed size and yields more with late and severe defoliation, and with lower plant populations. Delayed harvesting during the dry season led to seed shedding and yield was at the maximum for only about one week.
Observations on Boron-deficient Oil Palms (Elaeis guineensis)
Authors: Rajaratnam J. A.
Published: October 2008

Complete nutrient ± boron treatments were imposed on seedling and young oil palms growing in sand and water culture. A number of symptoms were observed on the boron-deficient palms, including the development of high endogenous auxin levels. The relation of morphological symptoms with IAA concentration is discussed. Comparisons were made of dry matter production, leaf area and leaf boron concentration.
Studies on Groundnut Mosaic Virus of Arachis hypogaea L. in West Malaysia
Authors: Poh Ting Wen , Lan Geh Swee , Chuan Lim Yau
Published: October 2008

A previously undescribed mosaic disease was observed on groundnut plants in several districts of West Malaysia. The virus was transmissible through sap, grafting and the aphids Aphis craccivora, A. gossypi, Myzus persicae, Rhopalosiphum maidis and Toxoptera citricidus. A. craccivora, the principal vector, shows dual transmission. The host range of the virus included mostly leguminous plants such as Glycine max, Cassia occidentalis, Crotalaria anagyroides, Indigofera hirsuta, Stylosanthes gracilis and Phaseolus vulgaris, and a non-leguminous host Chenopodium amaranticolor. The longevity in vitro of the virus was between 40–48 hours, its thermal end-point between 63° and 65°C and the dilution end-point 10−4.
Field Trials with Canadian Wonder Beans in Malawi
Authors: Spurling A. T.
Published: October 2008

In fifteen field trials withPhaseolus vulgariscv. Canadian Wonder time of planting was the most important factor affecting yield of dry beans in the Shire Highlands of Southern Malawi. Under-cropping maize with beans had no deleterious effect on the yield of maize and gave a worthwhile yield of beans. Little response was found to different plant populations when conditions for growth were good, but when conditions were poor yields were greatest from the highest population of 47,000 plants per hectare. A response in yield was obtained from 11 kg. N ha.−1but there was no effect of source of nitrogen or response to phosphate, potash or inoculation.
Effects of Nitrogen and Phosphate on Cenchrus Ciliaris at Ukiriguru, Western Tanzania
Authors: Walker B.
Published: October 2008

At Ukiriguru, Western Tanzania, three experiments over 4 years investigated the effects of nitrogen (up to 240 kg. N/ha.) and phosphate (up to 50 kg. P/ha.) on a Cenchrus ciliaris pasture. Dry matter yield increased with up to 160 kg. N and dry matter content also increased with nitrogen, whereas crude protein contents were initially lowered and then increased by the higher rates of nitrogen. These differences are attributed to changes in the leaf/framework ratio. The crude protein yield increased with each nitrogen level. Sulphate of ammonia markedly lowered the soil pH. The only responses to phosphate were when it was cultivated into the top soil, when there was a small increase in yield and a fall in crude protein.
Application, Absorption and Translocation of Boron in Oil Palm
Authors: Rajaratnam J. A.
Published: October 2008

The effects of different frequencies and rates of application of boron fertilizer were studied with regard to uptake of boron by the oil palm. The results indicated that annual or biannual application of this element maintained satisfactory levels in the leaf tissue. Heavy potassium fertilization was found to inhibit boron uptake but nitrogen had no effect.
Effects of Plant Density on Growth and Yield of Oil Palm
Authors: Corley R. H. V.
Published: October 2008

Crop growth rate of oil palm increases with leaf area index (LAI) to about 40 tons/ha./yr at the highest LAIs obtained. Net assimilation rate and dry matter production per palm decrease with increasing LAI, but the amount of dry matter per palm incorporated in vegetative tissues is unaffected by density. As a result the optimal LAI for oil yield is considerably below the critical LAI for maximum crop growth rate.
Effects of Defoliation and Topping on Semi-Upright Cowpeas [Vigna Unguiculata (L.) Walp.] in a Humid Tropical Environment
Authors: Ezedinma F. O. C.
Published: October 2008

The yield of cowpeas could be increased by judicious defoliation of the older leaves or by topping the growing apices at the onset of flowering. Limited defoliation at the pre-flowering stage did not reduce the yield of beans significantly but severe defoliation at any stage prior to maturity drastically reduced yield. Satisfactory yields of cowpea could be obtained by maintaining only about one-half to two-thirds of the potential leaf-area of the plants, suggesting that a reduction in the number and area of leaves, coupled with a better display of the fewer remaining leaves, could make cowpeas more productive than hitherto.
Effects of Irrigation, Mulch and N-Fertilizers on Yield Components of Arabica Coffee in Kenya
Authors: Cannell M. G. R.
Published: October 2008

Irrigation, mulch and N-fertilizers increased the yield of fresh fruit/tree by 66 per cent due to increases of 42 per cent in the number of fruiting nodes/tree, 14 per cent in number of fruits/node and 15 per cent in fresh weight/fruit; these three yield components accounted for 42, 13 and 6 per cent of the variation in yield among all treatment combinations. Bean/fruit weight ratios and times of flowering were not affected. Correlations between yield components were positive, suggesting that still more nodes could be produced per tree and per unit area before physiological limits to yield were reached.
Movement and Accumulation of Boron in Some Malaysian Soils
Authors: Rajaratnam J. A.
Published: October 2008

The leaching of boron, studied after high rates of application under different management practices, indicated that leaching was rapid and that the presence of cover crops was likely to reduce the immediate availability of boron to the main crops.
Incidence and Control of Iron Deficiency Chlorosis in Fruit trees in Iran
Authors: Bolle-Jones E. W. , Sanei F. , Pahlavani A.
Published: October 2008

Soil analysis on samples taken from apple orchards in Khorasan and quince orchards in Esfahan, suggested that at a sampling depth of 20–45 cm., the critical soil concentration of calcium carbonate at which chlorosis might appear seems to be 14–15 per cent for apple and 39–40 per cent for quince. The incidence of lime-induced chlorosis was accompanied by lowered leaf Ca/K ratios. The application of various iron chelates to chlorotic trees not only benefited yield of apples but also exercised a residual effect in succeeding seasons.
Nematodes in Stored Yams
Authors: Thompson A. K. , Been B. O. , Perkins Cynthia
Published: October 2008

Preliminary observations on tubers of yam (Dioscorea spp.) showed that there were increases in nematode populations during storage at ambient temperatures, whereas nematode counts were very low after storage at lower temperatures (12–13°C). Hot water treatments (50°C) for different lengths of time reduced the number of nematodes but damaged the tubers. Fumigation with methyl bromide, ethylene dibromide and hydrogen phosphide was not successful, as concentrations which reduced nematode numbers caused injury to the tubers. The effect of ethylene dibromide was not lasting.
Effect of Day-Length and Water on Nodulation of Cowpea (Vigna Unguiculata (L.) Walp.) in Ghana
Authors: Doku E. V.
Published: October 2008

Nodule and plant dry weight of five photoperiodically different cowpea varieties increased with increasing day-length. There were no effective nodules on any varieties in 8-hour days and the response of nodulation to day-length was greater than plant dry weight. Nodule and plant dry weight also increased with increasing availability of water, but at the highest watering rate nodule weight was significantly lower under long than short days. Cowpea should nodulate well under tropical day-lengths provided enough water is available.
Visual Symptoms of Some Mineral Deficiencies on Pyrethrum (Chrysanthemum Cinerariaefolium)
Authors: Pinkerton A.
Published: October 2008

Visual symptoms of deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, sulphur and boron on pyrethrum are described, and compared with those observed previously on other species of chrysanthemum.
Correlation Studies of Some Agronomic Characters in Sesame
Authors: Khidir M. Osman , Osman H. El Gizouli
Published: October 2008

In 90 local sesame types there was some association between seed coat colour and seed size, stem height, number of branches, number of pods, yield per plant and earliness. Forty-five coefficients show the degree of correlation between ten agronomic characters. Yield was significantly and positively correlated with all characters except the number of days to first flowering and to first maturity. Stem height, number of pods per plant and seed size seem to be the best criteria for selection in sesame.
Breeding and Testing Dwarf Sorghums in Nigeria
Authors: Andrews D. J.
Published: October 2008

The development of the first group of short-statured, late-maturing sorghum lines and hybrids and their initial testing for the Northern Guinea and sub-Sudan Savanna zones in Nigeria is described. The necessity of developing such types of sorghum is discussed, together with some of the problems encountered when breeding the new types.
Effects of Spraying and Cultural Practices on Cotton in Uganda
Authors: Davies J. C.
Published: October 2008

Trials on cotton in Uganda show that four DDT sprays give substantial increases in yields and a reduction in percentage of stained cotton. Benefits were obtained from early ploughing prior to sowing and there were positive interactions between time of ploughing and spraying. Fertilizer applications of superphosphate and sulphate of ammonia generally produced marginal benefits but more cotton was obtained from fertilized plots if they were sprayed, though not if unsprayed. The effect of fertilizer on the pest complex was slight, though one pest appeared to be attracted to lush fertilized cotton. Spraying gave excellent control of bollworms and mirids.
The Effect of Photoperiod on Development on Soyabean and Cowpea Cultivars Grown in the U.K. in Summer
Authors: Huxley P. A. , Summerfield R. J. , Hughes A. P.
Published: October 2008

Various sequences of different daylength regimes were given to five potentially tropically-adapted soyabean and three cowpea cultivars, to establish the duration of the photoinductive period which is necessary for their subsequent satisfactory development for experimental trials in the U.K. in long summer days. Genotypic differences in response to photoperiodic delay of flowering were clearly distinguished, but unless these soyabean and cowpea cultivars were kept in short photoperiods for at least 49 days, flower retention and pod development were adversely affected when they were subsequently planted in natural U.K. long summer days. The developmental stages from juvenility to flowering are discussed.
Effects of Temporary Water-tables on Marsh Grapefruit Trees in Sudan
Authors: Abbadi S. B. , Minessy F. A. , Abdelhafeez A. T.
Published: October 2008

Two weeks after irrigation there was a temporary water-table between 30 and 127 cm. below the soil surface in four different parts of a grapefruit orchard. As the temporary water-table rose closer to the soil surface the percentage of soil water in the root zone increased and tree size, number of leaves per branch, and leaf size all decreased. Shallow water-tables also induced more die-back and reduced yields significantly. Analyses of soils at various sites indicated that there was no problem of salinity or alkalinity, but physical soil analyses showed that the percentage of clay increased with increased shallowness of the water-table, in line with the soil moisture characteristic curves.
Effects of Mulches and Type of Seed Bed on Pearl Millet (Pennisetum Typhoides) under Semi-arid Conditions
Authors: Ali Masood , Prasad Rajendra
Published: October 2008

A field experiment was conducted for two years to study the influence of type of seed bed and various mulcheson yield and nutrient uptake by pearl millet, and on moisture conservation, under the semi-arid conditions of Delhi. A flat seedbed stored more moisture, gave significantly higher yield of pearl millet, and increased the uptake of N, P and K, compared withridge and furrow beds. Mulches were effective in conserving moisture, with straw mulch significantly better than dust mulch inits effect on crop yield and nutrient uptake.
Effects of Previous Crop on Yield and Nitrogen Response of Maize at Samaru, Nigeria
Authors: Jones M. J.
Published: October 2008

Maize yields were significantly affected by the nature of the previous crop. Maize following groundnuts significantly outyielded maize following cotton, which in turn significantly outyielded maize following sorghum or cowpeas, and this order was largely independent of the nitrogen fertilizer regime applied to the maize. Analyses of soil and crop showed that groundnuts increased nitrogen availability in the topsoil, but there was little evidence of any similar advantage after cowpeas.
Use of Phenol Colour Reactions for Identification of Rice Varieties
Authors: Sivasubramanian S. , Ramakrishnan V.
Published: October 2008

A phenol colour reaction test was found to be useful for classifying rice varieties. The degree of colouration varied between varieties and could be explained by differences in the enzyme activity, expressed as phenoloxidase and peroxidase. Light, temperature and aeration appeared to influence colour development, but age and crop location did not. A concentration of 1.5 per cent was found to be suitable.
The Wilting Point and Available Moisture in Tropical Forest Soils of Nigeria
Authors: Obi A. O.
Published: October 2008

Availability of soil water was investigated and the methods of determining the lower limit of availability by biotic and standard 15-bar pressure were compared. Greenhouse-grown sunflower and okra were the test crops for the biotic method. The pressure membrane equipment was used for standard 15-bar moisture determination. Okra and sunflower took up water beyond the standard 15-bar tension, thus lowering the moisture content at moderate wilting below the generally accepted values. In topsoil okra wilted at very high tensions, but at somewhat lower tensions in subsoil samples, unlike sunflower which wilted at higher tensions in subsoil samples. An equation is given which may be used to estimate the moisture content at the moderate wilting point of plants with known wilting tensions.
Isotope Studies on the Efficient Use of P-Fertilizers by Coffea arabica in Kenya I. Uptake And Distribution of P32 from labelled KH2PO4
Authors: Patel R. Z. , Kabaara A. M.
Published: October 2008

Uptake of P32 from labelled KH2PO4 solutions, injected in the top-soil at points distributed over 4000 cm.2 in the zone of high root activity, was measurable soon after application with accumulation of P32 in leaves increasing thereafter with time. The recently-acquired P32 was distributed uniformly in the tree canopies. Uptake of P32 reached a maximum when the number of injection points was increased from 15 to 30 per tree, with 45 and 60 injection points leading to little further change in P32 content of leaves. In the zone of high root activity, strip application of P32 was as efficient as application in a circle around each tree. The practical implications of these observations in relation to P-fertilization of coffee are discussed.
Cytological Investigations of the Family Theaceae—II. Cytology of a Triploid Tea
Authors: Bezbaruah H. P.
Published: October 2008

Cytological investigations carried out on a natural triploid tea plant revealed its alloploid origin. The plant is partially fertile and produces viable gametes with various chromosome numbers.
Yield and Yield Components of Six Sweet Potato (Ipomoea batatas) Cultivars II. Variability and Possible Sources of Variation
Authors: Lowe S. B. , Wilson L. A.
Published: October 2008

Variabilities in total yield, marketable yield and components of yield (tuber numbers and mean tuber weights) were studied in six sweet potato cultivars over two seasons, in crops harvested at two dates. Yield variability was high, particularly in marketable tubers, and was related to either or both components of yield. High-yielding cultivars had lower variabilities and the commercial cultivar 049 the lowest. The contribution of yield components to variability in total yield was evaluated and sources of yield variation were attributed to planting material, tuber development and season.
Effect of Age of Seedlings at Transplanting on Growth and Yield of Rice Varieties (Oryza Sativa)
Authors: Singh D. N. , Bhattacharya A.
Published: October 2008

Optimum transplanting age and relative growth rate in three groups of rice varieties differed with types and maturity periods. Transplanting 52 day old seedlings reduced the shoot number, and the magnitude of reduction was higher in early than in mid-early and medium varieties. Early transplanting reduced the number of days to flowering in all three groups compared with transplanting later. Senescence was much earlier in early types transplated as 52 day old seedlings. Grain production in early types was more sensitive to late transplanting than the mid-early and medium types. Medium varieties outyielded the early and mid-early ones when transplanted at 38 days after seeding.
Water Conservation in Three Grain Crops in the Zambezi Valley
Authors: Honisch O.
Published: October 2008

The results of a three-year water conservation trial in the Zambezi Valley of Zambia are reported, for an area characterized by high temperatures and low, often poorly distributed, rainfall, with low infiltration and high evapotranspiration rates. As a result of these conditions local farmers often produce grain crops yielding as little as 200–300 kg./ha., though considerable increases could be obtained by simple water conservation methods. Of four treatments, tieridges made before the start of the first rains consistently gave the heaviest yields. Mean yields of the three crops under trial (maize, sorghum and bulrush millet) were higher on tie-ridges than on conventionally prepared seedbeds by 168, 159 and 17 per cent in the 1968–69 to 1970–71 seasons respectively.
Correlation and Path Coefficient Analyses in Fodder Cowpea (Vigna sinensis Endl.)
Authors: Dangi O. P. , Paroda R. S.
Published: October 2008

The genotypic and phenotypic correlations and path-coefficients were studied in two different environments, using twenty fodder genotypes of cowpeas. Among quantitative characters, leaves/plant, branches/plant and stem girth were highly correlated with both green and dry matter yield, whereas among quality characters, total protein (per cent) showed significant association with digestibility (per cent). Based on path-coefficient analysis, leaves/plant and protein (per cent) were found to be the most important component characters. These two characters were also highly correlated at both the genotypic and phenotypic level and, therefore, selection based on leaves/plant is likely to be useful for simultaneous improvements in yield and quality of fodder in cowpeas.
Effects of Cutting Lengths on Sweet Potato Yields in Sierra Leone
Authors: Godfrey-Sam-Aggrey W.
Published: October 2008

Effects of cutting lengths on tuber yields and vine production of Missus and Madam sweet potatoes, as influenced by two different fertilizer regimes, were studied on Njala upland soils of Sierra Leone. Cuttings 61 cm. long gave significantly the highest tuber yields for both early-maturing cultivars when fertilized with 336 kg. sulphate of ammonia, 112 kg. basic slag, 448 kg. sulphate of potash, 841 kg. lime and 340 kg. sulphate of magnesium per ha. in two split applications a month apart. Fertilized with 502 kg./ha. sulphate of ammonia per application for 4 applications, 61 cm. long cuttings again gave the highest vine production. The lower the vine/tuber ratio, the higher the tuber yield.
Undersowing Rice (Oryza sativa) with Stylosanthes guyanensis. I. Plant Density
Authors: Shelton H. M. , Humphreys L. R.
Published: October 2008

Upland rice and Stylosanthes guyanensis were sown simultaneously in pure and mixed culture at varying densities at Na Pheng, central Laos. Vegetative growth of the rice was negatively related to stylo density over the range o to 81 stylo plants/m.2 Rice grain yield varied from 98·4 gm./m.2 in monoculture to 63·4 gm./m.2 when grown with 81 stylo plants/m.2 Rice was more competitive than stylo, but stylo growth was relatively independent of rice density over the range 20 to 120 rice plants/m.2
Undersowing Rice (Oryza sativa) with Stylosanthes guyanensis. II. Delayed Sowing Time and Crop Variety
Authors: Shelton H. M. , Humphreys L. R.
Published: October 2008

Simultaneous undersowing of upland rice with Stylosanthes guyanensis at Khon Kaen, north-east Thailand did not affect vegetative growth of rice but reduced grain yield by 19 per cent. Grain yield was not significantly affected if stylo undersowing was delayed by 10 days. Stylo growth was reduced by one half by delayed sowing and was negatively related to dry matter yield of rice variety.
Undersowing Rice (Oryza sativa) with Stylosanthes guyanensis. III. Nitrogen Supply
Authors: Shelton H. M. , Humphreys L. R.
Published: October 2008

The growth and nitrogen yield of Stylosanthes guyanensis undersown with upland rice were negatively related to level of urea application at Khon Kaen, north-east Thailand. In the absence of applied urea the nitrogen yield of rice monoculture was 3·3 gm./m.2 whilst the addition of stylo increased nitrogen yield of the association to 9·6 gm./m.2 Stylo was initially dominated by rice but exploited environmental growth factors more effectively in the latter part of the growing season, accentuating competition for water and phosphorus. Simultaneous stylo and rice sowing reduced rice grain yield by 12 per cent, the greatest reduction occurring at a low level of urea application, mainly due to abortion of spikelets after panicle exsertion.
Nutrient Requirements of Tomatoes (Lycopersicon esculentum) in S.W. Nigeria. I. Effects of N, P and K on Yields
Authors: Sobulo R. A. , Fayemi A. A. , Agboola A.
Published: October 2008

The response of tomatoes to applied N, P and K was determined in six trials in the forest and savannah zones of Nigeria. In the savannah area, N was the most deficient nutrient, with an optimum level of 60 kg. N/ha., while P and K were required at lower rates of between 20–60 kg. P2O5 and K2O/ha. depending on initial soil nutrient status and moisture availability. In forest soils developed from sedimentary rocks, P requirement was high (120 kg. P2O5/ha.) and response to N was small, but K could be important on the well-drained soils in this area because of low K reserves (0·1 per cent total K) compared with soils from igneous rocks in the savannah with more than 0·6 per cent total K. The potential of the savannah for large-scale tomato production is discussed, as well as factors limiting yields in Western State of Nigeria.
Nutrient Requirements of Tomatoes (Lycopersicon esculentum) in S. W. Nigeria. II. Foliar Analysis for Assessing N, P and K Requirements
Authors: Sobulo R. A. , Fayemi A. A. , Agboola A.
Published: October 2008

The fifth leaf of tomato plants sampled at the early flowering stage (seventh to eighth week after sowing) gave good assessments of N, P and K requirements of the tomato crop growing in the field but total N was less useful than nitrate-nitrogen for diagnosing nitrogen needs. The levels of critical N, P and K in the crop were 0·4 per cent NO3-N, 0·4 per cent P and 4 per cent K, with severe deficiencies when levels were less than 0·1, 0·15 and 2 per cent respectively.
Correlations, Path Analyses and Selection Indices for Castorbean (Ricinus communis L.)
Authors: Salih S. H. , Khidir M. O.
Published: October 2008

Genotypic correlations and path coefficients were used to determine the importance of various characters as components of yield in castorbean. Number of primary branches per plant and 100-seed weight had high positive correlations with yield per plant and with each other. Oil content was significantly and positively correlated with 100-seed weight. The path analysis revealed that number of clusters per plant, number of branches, height at maturity and yield of the first spike had the highest direct effect on yield per plant. Sixteen selection indices were constructed using these four yield components, the index combining all four being about 54 per cent more efficient than straight selection based on yield alone.
Water Relations of Beans. III. Pod and Seed Yield of Haricot Beans Under Different Irrigation in the Sudan
Authors: El Nadi A. H.
Published: October 2008

Equal volumes of irrigation water, applied in different ways to a crop of haricot beans in two seasons, showed that the best practice was 60 mm. irrigation every ten days.
Effects of Lime and Fertilizer on Natural Pastures in Brazil
Authors: Olsen F. J. , Santos G. L.
Published: October 2008

The application of lime to natural pastures in Rio Grande do Sul, Brazil, did not increase herbage yields, but nitrogen fertilizer, alone and in combination with phosphorus fertilizer, enhanced dry matter productivity significantly. Dry matter yields of the natural pasture were more than doubled at the highest fertilizer rate, though the botanical composition of the sward was only modified slightly by various lime and fertilizer treatments.
Resistance of 20 Cultivars of Onions (Allium cepa) to Rotting and Sprouting during High-Temperature Storage
Authors: Stow J. R.
Published: October 2008

Bulbs of 20 onion cultivars were stored at 30°C and assessed for rotting and sprouting. No evidence of heritable resistance to high-temperature rotting was found, but the suppression of sprouting by high temperatures appeared to be a common character of onion cultivars.
Effects of Cycocel on Crop Plants in Sierra Leone I. Groundnut (Arachis hypogea)
Authors: Das Gupta D. K.
Published: October 2008

The response of groundnut plants to CCC was investigated by applying concentrations of 0, 500, 1000 and 1500 ppm three times as a foliar spray. CCC at 500 ppm gave more kernels, and heavier yields of pods, kernels and oil, than 1000 or 1500 ppm or the control treatment. Application of CCC resulted in a greater percentage of shell and of moisture in the whole pod than in the control.
Effects of Sowing Date on Growth, Development and Yield of Photosensitive Sorghum at Samaru, Northern Nigeria
Authors: Kassam A. H. , Andrews D. J.
Published: October 2008

Performance of Short Kaura, a photosensitive Nigerian sorghum, was compared at Samaru in ten sowings in 1972. Except for a two-week interval between the fifth and sixth sowings, all sowings were at weekly intervals from 12 May to 21 July. Total dry weight and grain yield decreased with delay in sowing after 26 May at the rate of 1700 kg.ha.−1 week−1 and 360 kg. ha.−1 week−1 respectively. Each week's delay in sowing after 12 May shortened the total growth cycle by 5·9 to 6·0 days, with 77 to 78 per cent in the vegetative phase, 7 to 8 per cent in the head development phase and 14 to 16 per cent in the grain filling phase. Although the date of head initiation seemed to be determined by photoperiod, sowing date also had a small but definite effect.
Rainfall Characteristics and Soil Erosion in the Rainforest Area of Western Nigeria
Authors: Wilkinson Guy E.
Published: October 2008

Precipitation in Western Nigeria is principally from thunderstorms with sharp, high-intensity rainfall peaks. The time of occurrence of the peak intensity period in a rainstorm has an influence on whether or not runoff occurs in smaller storms. Runoff and soil loss on bare, cultivated Iwo soil are closely related to an EI30 erosivity index, modified by the time-position of the peak intensity. The soil erodibility factor in the universal soil-loss equation could be reasonably estimated from easily measured soil parameters.
Effect of Nitrogen on Nodulation and Yield of Soybean
Authors: Olsen F. J. , Hamilton G. , Elkins D. M.
Published: October 2008

Nitrogen fertilizer applied to the surface of the soil in the field did not increase the yield of Bragg soybeans, and at higher levels reduced it, but may or may not significantly reduce soybean nodulation and plant height. In a pot experiment, there was evidence that deeply applied N increased plant height and dry weight of a non-nodulating isoline of Clark soybeans 46 days after planting.
Effects and Interactions of ‘Package Deal’ Inputs on Yield and Labour Demand of Maize
Authors: Baker E. F. I.
Published: October 2008

Effects of sowing dates, population, fertilizer, weeding and variety inputs on yield were measured, as well as labour required to apply the inputs. Sowing date was the most important, response to others being dependent upon this factor. Population was least important, but increased in value as fertilizer level was raised. Labour requirements were so increased by applying the ‘package’ that subsistence farmers, whose families are fully occupied as the sole source of labour, would be unable to cope without reducing the area under cultivation. Thus yield response to a package must be higher than hitherto considered acceptable, and the risk of not obtaining this increase probably contributes to the rejection of such recommendations by subsistence farmers.
Evaluation of Yield, Variability and Quality of Sweet Potato Cultivars in Sub-Tropical Australia
Authors: Huett D. O.
Published: October 2008

The yield, variability and quality of 16 sweet potato cultivars, harvested after 21 weeks growth, were evaluated in sub-tropical Australia. The coloured-flesh cultivars L8-92, Centennial, HAC-Pink, Copperskin Goldrush and Nemagold produced yields of marketable storage roots in excess of 19,000 kg ha−1, which was three to four times the yield of the local commercial cultivar, White Maltese. The high variability in mean yield per plant of all cultivars offers scope for selection within cultivars. Those with a deep orange flesh and high soluble solids content, i.e. L8-92, Copperskin Goldrush and Centennial, were preferred by members of a taste panel. A high carotene cultivar L8-92 has the greatest commercial potential because it produced the highest yield of marketable storage roots and had the highest taste panel rating for eating quality of stored roots.
Genotype-Environment Interactions in Wheat: Effects of Temperature on Coleoptile Length
Authors: Bhatt G. M. , Qualset C. O.
Published: October 2008

Temperature effects on coleoptile development were studied in 18 genotypes of spring and semi-winter wheats, illustrating a simple experimental approach for choosing genotypes and management practices that would minimize genotype–environment interactions for stand establishment.
Manifestations of Heterosis in Grain Sorghum
Authors: Kambal A. E. , Abu-El-Gasim E. H.
Published: October 2008

The magnitude of heterosis for 15 characters was studied in ten sorghum hybrids, produced by crossing ten restorer varieties with male-sterile Combine Kafir 60 as a common female parent. The most evident expressions of heterosis were higher yield and increased vegetative growth, often associated with delay in flowering. The increase in yield of the hybrids over their superior parents, ranging from 35 to 238%, resulted mainly from an increase in number of grains per head, rather than from an increase in the weight of individual grains. The regressions of hybrids on male parents, and the correlations of yield with other characters were studied, and the prospects of producing adapted hybrids for the Sudan are briefly discussed.
Chemical Weed Control in Groundnuts in the Kenana Area of the Sudan
Authors: Hamdoun A. M.
Published: October 2008

Herbicides tested at Kenana Agricultural Research Station (K.A.R.S.) from 1968 to 1972 showed that pre-emergence application of oxadiazon, nitrofen, linuron, phenobenzuron, prometryne, nitralin, diuron and fluorodifen gave satisfactory weed control. Applications of oxadiazon at 2·38 kg/ha, fluorodifen at 7·14 kg, nitrofen at 4·76 kg and nitralin at 3·8 kg had no adverse effect on growth of groundnuts, but prometryne, diuron, phenobenzuron and linuron at relatively lower rates caused phytotoxicity symptoms. Residues from treatment with 7·14 kg fluorodifen, 2·38 kg oxadiazon and 4·76 kg alachlor did not injure test crops, but growth of sorghum and maize was reduced 9 months after applying 3·8 kg nitralin. Phenobenzuron was persistent in soil and most test crops were injured following an application of only 1·9 kg.
Relative Efficiency of the Randomized Complete Block Design
Authors: Abou-el-Fittouh H. A.
Published: October 2008

The efficiency of the randomized complete block design, relative to the completely randomized design, is linearly expressed as: Relative efficiency=A+CF, where A and C are constants determined by the number of treatments (t) and blocks (b) and F=calculated F value for blocks in the ANOVA table. For values of t and b ranging from 2 to 10 the constants A and C are estimated. Curves of relative efficiency are given when o≤F≤10 for t values ranging from 2 to 10 when b=4, 6 and 8.
Effect of Split Application on N Uptake by Wheat from N15 Labelled Ammonium Nitrate and Urea
Authors: Hamid A. , Sarwar G.
Published: October 2008

The effect of split application of N on the uptake of N by wheat from N15 labelled ammonium nitrate and urea was studied in the field. Nitrogen fertilizers were applied at 120 kg N/ha in a single application (at seeding); two split applications (at seeding and tillering); and six split applications (at seeding, tillering, boot, heading, flowering and the milky stage). Nitrogen applied in two splits was most productive for grain yield for both the N sources, but six split applications significantly increased the protein content in grain compared with single or two split applications. The utilization of N from ammonium nitrate in grain was significantly higher than from urea when applied in six split applications.
Chemical Preservation of Partially Dried Potato Pulp
Authors: Lacey J. , Pirie N. W.
Published: October 2008

Mechanically dehydrated potato pulp containing up to 50% dry matter was stored, without visible deterioration, for up to 25 weeks after treatment with at least 0·3% of propionic acid. Wetter pulps required more acid for satisfactory preservation. Thorough mixing was important if maximum storage periods were to be achieved. Ammonia was less satisfactory as a preservative. No visible deterioration occurred while ammonia vapour was present, but bacterial growth was still found even after the addition of about 0·7% ammonia to pulp containing 40–45% dry matter.
Methods of Bringing Tea into Bearing in Relation to Water Status During Dry Weather
Authors: Carr M. K. V.
Published: October 2008

Despite large visual differences in size and form of shoot and root systems of young clonal plants and of older seedlings, there was no convincing evidence that tea plants, brought into bearing by pegging, are necessarily more susceptible to water stress than similar plants that have been pruned, though the sap tension in pegged plants of one clone was often greater than in similar pruned plants. Further studies are needed to show whether this is the case in drier areas, but differences in responses to dry conditions by individual clones appear to be of greater significance.
The Stability of Rice Yields in Sri Lanka
Authors: Ganashan P. , Whittington W. J.
Published: October 2008

The stabilities of plant height and yield for rice varieties grown in Sri Lanka were calculated by regression analysis. High yields were produced by both stable and unstable varieties in the wet season, but in the dry season high-yielding varieties tended to be of above-average stability. The yield of the newer, shorter varieties exceeded those of older varieties except at low nitrogen levels, and the new varieties were of above-average stability.
Population × Environment Interactions in Maize Trials and their Implications on Testing Procedures
Authors: Obilana A. Tunde , Fatunla Tunde
Published: October 2008

The important interactions in a 2-year maize trial were population × location, location × year and population × year × location, and our analyses suggest that eight locations, two years and three replications will allow the detection of a 5% differential in yield. The most effective way of obtaining the true value of a variety is by increasing the number of years, and the least effective is by increasing the number of replications. Since locations can be effectively substituted for years, increasing the number of locations will expedite the release of improved cultivars.
Leaf Fall in Cassava
Authors: Rosas C. , Cock James H. , Sandoval G.
Published: October 2008

Trials on leaf abscission of cassava led to the conclusion that the leaf lamina is necessary, and must receive light, to prevent abscission of the petiole. The abscission rate of old leaves is increased by the presence of an active apex, but is not affected by the carbohydrate requirements of the roots.
Effects of Grain Formation on Dry Matter Distribution and Forage Quality in Maize
Authors: Bunting E. S.
Published: October 2008

Post-anthesis trends in yield and forage quality of dry matter in components of the maize shoot were studied in experiments with barren and fertile plants grown at 10 plants/m2. In fertile plants, which had a maximum shoot DW 6 or 7% higher than barren ones, the stems (including leaf sheaths) yielded 5 t/ha (42% shoot DW) 30 days after flowering, declining to 3·5 t/ha (26% DW) at final harvest 60 days later. During this period the ear increased by more than 4 t/ha, from 23 to 50% of shoot DW, whereas in barren plants there was little change in DM distribution, with the stem representing about 48% shoot DW, leaf and husk together 40–45% and the ear (rachis only) less than 10%. DM percentage of shoots was similar in barren and fertile plants until maximum DW was attained about 60 days after flowering, after which fertile plants dried more rapidly. In vitro dry matter digestibility was as high in barren as in fertile plants, and the analytical data on forage quality do not suggest that it was positively associated with grain content.
Effects of Rate and Time of Nitrogen Application on Yields of Cotton in Northern Nigeria
Authors: Smithson J. B. , Heathcote R. G.
Published: October 2008

Trials to determine the optimal rate and time of nitrogen application to cotton were conducted at three sites for three seasons. The results indicate that nitrogen is used most efficiently when applied at relatively low rates, with at least half the application delayed until flowering. Early application leads to the incorporation of a greater proportion of the nitrogen into the vegetative structures which, at lower rates, may leave insufficient for fruit development. With late application a greater proportion of the nitrogen is utilized in reproductive growth, although full utilization may not be achieved at higher rates.
Research-based Recommendations versus Farmers' Practices: Some Lessons From Cotton-Spraying in Malawi
Authors: Farrington John
Published: October 2008

The discrepancy between farmers' performances and research-based recommendations in the control of cotton pests in Southern Malawi is discussed. Analysis of the former in two seasons revealed that the farmers' low levels of insecticide application approached the economic optimum, whereas several factors of economic importance were omitted from the research-based justification of high spraying levels. Recommendations for improving the applicability of research recommendations to smallholder farming are made, with particular reference to the farming risks that arise from uncertain rainfall, the wide range of farming ability encountered in practice, and the dangers of atypically high levels of management in research experiments.
Influence of Plant Density and Nitrogen on Yield and Milling Quality of Lowland Rice in Nigeria
Authors: Fagade S. O. , Ojo A. A.
Published: October 2008

In experiments conducted with three rice varieties at different plant populations and N levels, the non-lodging varieties responded to 150 kg N/ha. The highest yield in non-lodging varieties were at the highest transplanted density, but at the lowest density in the lodging variety. The percentage of total milled rice of all varieties was not significantly affected by N application, which improved head-rice recovery in chalky IR-8, but had no significant effect on non-chalky varieties. Competition for nutrients could be a major factor limiting head rice return at high densities.
Short-term Prediction of Cotton Yields in the Sudan Gezira
Authors: Bartsch Reinhart
Published: October 2008

This paper attempts to determine the relations between weather and cotton yields in the Gezira Scheme in the Sudan, and to establish a prediction function with climatic factors as variables. The precision of the function established to forecast the final yield in April will as yet be low, when based on the information available at the end of October, November or December. A significantly better yield forecast can be made at the end of January. Variables of the prediction function are temperature, humidity, radiation and evapotranspiration. A strategy is proposed to improve early forecasts step by step, by making further forecasts at later stages.
The Effects of Plucking Policies on the Yield of Tea in Malawi
Authors: Palmer-Jones R. W.
Published: October 2008

There have been conflicting reports of the effects of different plucking (harvesting) policies on yields of tea in Malawi. An experiment is reported which separates the effects of plucking round length from those of plucking standard, and is compared with the results of simulating those plucking policies. Between the experiment and the simulation the conflict is resolved, and the validity of the experiment and simulation model are thereby enhanced. The immediate practical implications of the work are limited because of the unquantified relations between plucking standard and quality and grade out-turn of made tea.