bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Plant Population on Sole-crop Cassava in Sierra Leone
Authors: Godfrey-Sam-Aggrey W.
Published: October 2008

Effects of plant population on mean yield and yield components of 2-year sole cassava crops were studied on Njala upland soils of Sierra Leone in two experiments. Increasing plant population of multi-shoot Cocoa cassava over 7000/ha decreased all the parameters studied except top/root weight ratio, which increased. The observed effects were attributed to competition for environmental resources, since area of land/plant unit decreased as plant population increased. The relations between plant populations and yields of fresh root and cortex dry matter were asymptotic, indicating that the respective yields were products of the vegetative phase of cropping.
Effects of Delayed Hand Weeding on Sole-crop Cassava in Sierra Leone
Authors: Godfrey-Sam-Aggrey W.
Published: October 2008

The effects of delayed hand weed control at 30-, 45-, 60-, 90-day intervals, and no weeding, on sole-crop cassava, was studied in two experiments on the upland soils of Sierra Leone. Timing and frequency of weeding were important in influencing root number and root yield, and delayed weed control depressed both attributes. The critical period of competition was in the 45-day weeding interval, with six weedings in a 14-month growing period. Rottboellia exaltata was the predominant species amongst the permanent grasses on the no-weeding plots.
Assessing Losses in Rice Due to Insects and Diseases in Bangladesh
Authors: Catling H. D. , Alam Shamsul , Miah S. A.
Published: October 2008

A series of 17 crop-loss assessments was made under simulated farmers' field conditions in the three main rice cropping seasons of Bangladesh. The main insect pests were the rice stem borers (Tryporyza incertulas, Chilo polychrysa, Sesamia inferens) and in the monsoon rice gall midge (Pachydiplosis oryzae). Disease incidence was negligible. In the winter and early monsoon yield losses averaged 4 and 6% respectively, but economic benefit was only derived from insecticide application in the monsoon season, when there was an average yield loss of 16%. An economic threshold of 5–10% damaged tillers (‘deadhearts’ and ‘onion shoots’) was indicated for early attacks of stem borers and gall midge. Possible reasons are given for the usually low incidence of insect pests and diseases in Bangladesh rice.
Fertilizer Responses of Cucumbers on Peat in Brunei
Authors: Williams C. N.
Published: October 2008

The effects on local cucumbers of supplementary mineral fertilizers over an initial field dressing of 30 tonnes of poultry manure and 4 tonnes of lime/ha, were determined on tropical peat soil in Brunei. Significant yield increases were obtained with supplementary N up to 280 kg/ha but not with K/Mg above the basal rates 78/10 kg/ha. The highest yields exceeded 50 tonnes/ha of marketable fruit, obtained over a 9-week growing period.
Effects of Drainage, Spacing and Fertilizer on Soyabeans in Paddy Soils in Brunei
Authors: Williams C. N.
Published: October 2008

The yield of Chipewa variety of soyabean was investigated in relation to spacing and fertilizer levels on a range of paddy soils exhibiting good, medium and poor drainage. Under good conditions of drainage optimum yield was obtained at a density of 100,000 plants/ha and a fertilizer level equivalent to N—54, P2O5—54, K2O—75 and MgO—9 kg/ha. Under poorer conditions of drainage yield continued to increase up to a density of 162,000 plants and fertilizer levels of twice the above rates. Even under sub-optimal drainage conditions, however, satisfactory yields equivalent to about 1500 kg/ha were obtained from this variety.
Supplementary Irrigation of Young Clonal Tea in Kenya. II. Internal Water Status
Authors: Othieno C. O.
Published: October 2008

Measurements of the stomatal apertures of young clonal tea plants (Camellia sinensis) showed that stomata of plants irrigated during the dry seasons only were wider open than those not irrigated during both wet and dry seasons. Similarly, xylem water potential values (ψx) were always higher (less negative) in irrigated than non-irrigated plants, during both wet and dry seasons. The results suggest that more drought-susceptible clones have a greater demand for water than those less susceptible to drought.
Comparative Net Photosynthesis of FourHevea brasiliensisClonal Seedlings
Authors: Samsuddin Zahar , Impens Ivan
Published: October 2008

Single-leaf net photosynthesisversuslight response curves of fourHevea brasiliensisclonal seedlings showed that it was possible to divide photosynthetic rates into high and low classes.
Evapotranspiration Measured by a Neutron Probe on Sudan Gezira Vertisols
Authors: Fadl Osman A. A.
Published: October 2008

Daily measurements of moisture by neutron probe showed an erratic pattern of ET in the Sudan Gezira, attributed to the redistribution of water and development of cracks in a drying profile. However, dividing an irrigation cycle into periods of 3–5 days revealed a unique trend of ET that was consistently low in the early period, increased to a maximum in the middle, and fell off at the end. Roots suffer from anaerobic conditions for about 5 days after flooding but subsequent drying and cracking improves soil aeration that leads to final depletion of profile moisture and depression of ET.
Effects of Nitrogen on Melon (Citrillus lanatus) at Ibadan, Nigeria
Authors: Ogunremi E. A.
Published: October 2008

Three experiments testing the effects of nitrogen on melon showed significant varietal differences. Nitrogen increased yields by increasing fruits/plant, seeds/fruit and seed weight, had no effect on fruit weight, size and husk, and increased leaf area through leaf number and leaf size. Fruit growth coincided with a rapid decline in leaf area, indicating that the mottled green fruits contributed appreciable assimilates towards their own growth. The implications of the findings, and the inefficiency of the crop in seed formation, are discussed.
Handling Missing Observations in the Two-way Analysis of Variance with Interaction
Authors: Abou-El-Fittouh H. A. , Taha E. O.
Published: October 2008

Three procedures for handling missing values in randomized block experiments with more than one observation per plot are examined, and their effects on the resulting expectations of mean squares in the analysis of variance studied. Using the average of the available observations in the plot in which the missing value occurs has the least effect on the validity of the tests of significance and on the estimation of variance components.
Effects of Soil Moisture and Organic Mulches on Corn Planted in Different Patterns
Authors: Reddy K. Anand , Reddy B. Bhasker , Balaswamy K. , Venkatachari A.
Published: October 2008

In a two-year study the yields and water use of corn were studied under four planting patterns, with different soil moisture regimes and organic (paddy straw) mulches. Normal planting and irrigation resulted in higher yields and lowest water use efficiency, while double file planting in deep furrows (rafter method) gave greatest efficiency of water use but with a slight decrease in grain yield. Mulches improved water use efficiency by 50–60% and reduced irrigation requirements by four to six irrigations. Under limited moisture conditions a combination of these practices is likely to reduce irrigation requirements by half and to double water use efficiency.
Forms for Recording Details and Results of Field Experiments
Authors: Riley J. , Ryder K.
Published: October 2008

This paper describes the design of six data-recording forms which have been found to be acceptable by both field workers and data-processing staff. The reasons for the choice of design and hints on how to present the data are also given.
Mixed Cropping in Northern Nigeria. III. Mixtures of Cereals
Authors: Baker E. F. I.
Published: October 2008

Alternate row mixtures of millet, maize and sorghum were compared with equivalent areas of sole crops. Yield of mixtures were rarely reduced but there was a gain when components differed by a certain margin in height or age at maturity, or both. Approximately 75% of variation in yield gain from mixing was attributable to these two factors. Subsistence farmers who mix a fast-growing early-maturing cereal with a slower-growing, later-maturing one thus reduce interference between neighbouring plants during the reproductive phase of growth, and obtain grain harvest spread in time and heavier than from equivalent areas of the component sole crops.
Effects of Soil Salinity on Broad Bean (Vicia faba) in the Sudan
Authors: El Karouri M. O. H.
Published: October 2008

The effect of soil salinity on growth and yield of broad bean was investigated, using correlation analysis. The salinity level at which 50% reduction in bean yield occurred was 9 mmho/cm. The negative correlation between dry matter production and yield and ECe, together with the field observations, indicated that soil salinity may be responsible for the different growth and yield of broad bean fields in the salt-affected areas of northern Sudan.
Effects of Seed Size on Growth and Yield of Maize in the Kenya Highlands
Authors: Hawkins R. C. , Cooper P. J. M.
Published: October 2008

Maize was grown from three batches of seed, with mean 1000-grain weights of 225, 432 and 649 g. Initial plant size was larger when grown from large seed, but development rates were similar for all three sizes and relative growth rates were similar during the early stages. Relative differences in plant size became smaller as the crop matured. Crop growth rates during the linear phase of dry matter production were the same, and there were no significant yield differences. Comparisons of leaf and spikelet initiation, and individual leaf size are also reported.
Seed Dormancy in Sesame (S. indicum) and the Effect of Gibberellic Acid
Authors: Ashri A. , Palevitch D.
Published: October 2008

Seed dormancy was found in the Mexican sesame cultivar Cola de Borrego but it disappeared about 6 months after harvest. Dormancy was completely broken by soaking the seeds in GA3 solutions of 100 and 500 ppm for 48 h; soaking in 1000 ppm GA3 concentration was helpful but not as good as the 100 and 500 ppm treatments. GA3 treatments also hastened emergence.
Traditional versus Improved Groundnut Practices: An Economic Analysis of Production in Northern Nigeria
Authors: Abalu G. O. I. , Harkness C.
Published: October 2008

This study examined the economic, technical, and social feasibility of an improved groundnut production technology at the farmer's level vis-à-vis traditional practices. Improved practices are shown to be superior, but several economic and technical issues are raised.
Effects of N Fertilizers on Sugarcane in the Sudan
Authors: Ibrahim Hassan Suliman
Published: October 2008

Three field experiments were conducted at Guneid, Sudan, in which N was applied to sugarcane (A) in one dose, (B) in split doses at 2 and 4 months, and (C) as a single dose 4 months from planting. Nitrogen application generally increased the yields of both cane and sugar but did not significantly affect sucrose recovery. Correlation coefficients for yields of cane and sugar suggested that the application of 88–176 kg N/ha 2 months after planting was economic.
Crop Production Potential and Energy Conversion Efficiency in Different Environments
Authors: Gibbon David , Holliday Robert , Mattei Francesco , Luppi Gaetano
Published: October 2008

A method of estimating crop production potential was devised and tested in a number of contrasting solar radiation climates. With increasing levels of solar radiation, total dry matter yields of kale, maize and sugar beet increased, whilst energy conversion efficiency declined in kale and sugar beet but increased in maize. Maximum potential crop yields in almost all environments were achieved with a conversion efficiency of approximately 2 per cent of total radiant energy.
Effects of Soil Fertility on Yield and Juice Quality of Sugarcane
Authors: Pande H. K. , Tilak K. V. B. R.
Published: October 2008

Application of nitrogen (160 and 80 kg. N/ha.) and phosphate (80 and 40 kg. P2O5/ha.) increased the diameter and height of cane and number of shoots per metre of row, and consequently the yield of minable canes, with significant differences between the effects of the two levels of each nutrient. Potash did not affect the growth and yield of sugarcane. Application of 80 kg. P2O5/ha. was beneficial only with 160 kg. N/ha. but 40 kg. P2O5proved effective with both 160 and 80 kg. N. because yield of millable cane with 80 kg. each of N and P2O5was significantly lower than with 80 kg. N + 40 kg. P2O5.
Effect of Competition in Jute
Authors: Chaudhuri B. B. , Basak S. L.
Published: October 2008

Competition was studied among four varieties of jute, one cultivated and one wild type of each of C. capsularis and C. olitorius. Varieties exposed to competition showed significant effects on different characters at species and variety level for all the characters. Variety competition, average competition except for base diameter, and specific competition except for node number and base diameter, were significant for all the characters. Wild forms were less effective than cultivated ones as competitors, and the action of one species on the other did not affect all growth parameters in the same way.
Estimates of Genetic and Environmental Variability in Sesame
Authors: Osman H. El Gizouli , Khidir M. Osman
Published: October 2008

Two years study was made on variability in 42 indigenous and exotic varieties of sesame. With very few exceptions, highly significant differences were found between the varieties for the 15 characters investigated. A wide range of phenotypic and genotypic variability was exhibited by all characters except oil, protein and moisture, and 9 out of 15 characters gave heritability estimates exceeding 80 per cent. To relate heritability values to other genetic parameters, a ‘rank procedure’ showed that the characters followed one another in a definite order.
Studies of Ripeners on Sugar Cane
Authors: Julien M. H. R.
Published: October 2008

The sugar cane ripener Mon O45, tested on three commercial sugar cane varieties, showed responses depending on variety, time of application, dosage rate and the interval between application and harvest. Age of crop at application appeared to have little influence on the response. The chemical was also shown to have growth inhibiting properties. The possible use of this chemical to increase sugar produced per unit area is discussed.
Studies of Ripeners on Sugar Cane
Authors: Julien M. H. R.
Published: October 2008

Mon O45 at rates of 4 and 6 kg./ha. was shown to increase total dry matter in the stem of the sugarcane variety M13/56, optimum response occurring at 9–12 weeks after application. The increase in dry matter was mainly due to an increase in sucrose, since the chemical had no effect on fibre and decreased reducing sugars. The site of action appears to be in the top 16 internodes. Possible modes of action of the chemical are discussed.
The Relative Performance of Forage Legumes as Rotational Crops in the Gezira
Authors: Musa M. M. , Burhan H. O.
Published: October 2008

A study was made of the nitrogen fixing systems of various forage legumes and their rotational effect on yield of subsequent cotton crops, as well as of yields of the different legumes. Phillipe-sara, clitoria and lubia out-yielded all the others. Nitrogen yields of the various forage legumes showed that they are active fixers of atmospheric nitrogen, but yields of cotton following the various legumes showed wide seasonal variability and were neither significantly nor consistently different in different seasons. On the other hand, the increase in cotton yield due to fertilizer nitrogen was highly significant, indicating a comparatively small end-of-season contribution of cut legumes to soil nitrogen. It was therefore difficult to differentiate between the legumes on the basis of any consistent ability to influence yields of following cotton, suggesting that the choice of a legume in the rotation should depend primarily on economic considerations.
Analysis of Growth Patterns in Cocoa Seedlings as Influenced by Bean Maturity
Authors: Adenikinju S. A.
Published: October 2008

Beans collected from immature pods of cocoa progency C77 × C23, as early as 15 weeks after pollination, successfully produced seedlings as vigorous as those from mature ripe pods. Seedlings produced by beans from 21-week-old pods were the most vigorous, with vigour based on the integral of all measured growth parameters (leaf number, leaf area, seedling height, girth and root weight). There were close correlations between these growth parameters on the one hand and bean maturity and seedling age on the other, the relations with the former being curvilinear and with the latter linear. Seedling age and bean maturity accounted for between 87–99 and 42–96 per cent respectively of the variations in growth parameters. Multiple regression equations are presented for quick estimations of leaf area.
A Quantitative Shatter Index for Soybeans
Authors: Quick Graeme R.
Published: October 2008

The object of the study was to find whether loss during combine harvesting was correlated with pod shattering propensity of soybeans. Mechanical pod shattering methods tested included vibration, impact, centrifugation, pod traction and compression. The influence of variety and moisture content on mechanically-induced pod shatter and on header losses was studied. The pod suture compression method was simplest to perform and, with respect to crop moisture, gave results indicative of machine harvest shatter levels. Such a standardized mechanical shatter index may prove a useful criterion in soybean breeding selection for harvest shatter resistance.
Agrometeorology in Uganda—A Review of Methods
Authors: Rijks D. A.
Published: October 2008

Unpublished, or not easily accessible, details are presented on the establishment of the agrometeorological network in Uganda and the collection, analysis and publication of the observations. Some of the agrometeorological research methods commonly used in Uganda are summarized.
Stomatal Infiltration Measurements as an Indicator of the Water Requirement and Timing of Irrigation for Cotton
Authors: Ofir M. , Shmueli E. , Moreshet S.
Published: October 2008

The single-liquid infiltration method of measuring stomatal opening was adapted as a practical field method for determining the time of irrigation of cotton. A number of different liquids, leaf positions and times of measurement were tested and the most sensitive method was selected on the basis of the results. No stomatal response was found while soil moisture was depleted to one-third of available water. A steep reduction in stomatal opening was observed with further drying of the soil. Some results are presented from an irrigation experiment where irrigation control by infiltration method was compared with other methods. The practical possibilities in the use of the method in field practice are discussed.
Seasonal Effects on the Root Nodulation of Legumes
Authors: Masefield G. B.
Published: October 2008

To investigate seasonal effects on nodulation of legumes during an English summer, plants of Pisum sativum and Phaseolus vulgaris were sown in pots in the open at intervals of 14 days between March and July and the pots were watered on all days when rain did not fall. The weight of nodules per plant varied significantly between sowing dates and showed seasonal trends in both legumes, but in different directions. In P. sativum nodulation was at a minimum at the midsummer sowing date but with P. vulgaris the mid-summer sowing gave maximum nodulation. The data are further analysed in terms of number and size of nodules, and nodule weight as a percentage of plant weight.
Chemical Changes in Some Nigerian Vegetables During Growth
Authors: Oke O. L.
Published: October 2008

The percentage dry matter of some Nigerian vegetables increases with age.Corchorus olibriusgave the highest yield of vitamin C after five weeks, but the stage of maturity had less effect with other vegetables. The oxalic acid content ofCelosea argenteawas very high, approaching a lethal level. It appears that some of the vegetables are best at about six weeks from sowing from the standpoint of eating quality, oxalic acid and vitamin C content.
Evaluation and Computation of Potential Evaporation in the Tropics
Authors: Rijks D. A. , Walker J. T.
Published: October 2008

The problems involved in the estimation of potential evaporation in the tropics are discussed, and available methods for calculating potential evaporation are assessed. A computer programme is described which evaluates Penman's formula, accommodating data from the very wide range of conditions experienced in tropical agriculture. The programme conforms with recent W.M.O. recommendations and is written for computers available in many parts of the world. An important component of the programme is a strict data validation procedure. The output includes daily and mean ten-day estimates of E, using the reflection coefficients for open water and for a crop as well as both calculated and, where available, measured values of radiation.
Extensive Trials with Perennial Crops on Smallholders' Fields in Africa
Authors: Robinson J. B. D.
Published: October 2008

Cultural standards and the husbandry techniques used on small farmers' fields are seldom the same as those practised on research and experimental Stations in the developing countries. The need for extensive agronomic experiments to be sited on small farmers' fields is emphasized. This method has been quite widely used with annual crops, but could with advantage be more generally adopted in perennial crops. Some of the advantages of this approach in agronomic investigations are illustrated by examples from work carried out in East Africa.
Emergence of Crops in Clay Soils of the Central Sudan Rainlands in Relation to Soil Water and Air-Filled Pore Space
Authors: Hack H. R. B.
Published: October 2008

Poor emergence of crops is common during the rainy season on the clay soils of the central Sudan. Arachis hypogaea, Sesamum indicum, Hibiscus cannabinus and Gossypium hirsutum were studied under a range of soil water and air-filled pore space conditions by sowing on earth ramps; these were covered with water which was subsequently drained either completely or so as to leave water standing. Air-filled pore space was estimated by air-picnometer and water content by oven drying. The conditions in the sloping beds were related to those normally found in experimental plots (using Triticum aestivum). When the effective air-filled pore space was as low as 10 per cent all crops emerged poorly. Sesame emerged well at 40 per cent and all others at 20 per cent. The best emergence was found when water was drained completely at the shortest interval included in the experiments, i.e. on the day after covering the beds.
Pre-Harvest Desiccation of Sugar Cane With Paraquat in Queensland
Authors: Arvier A. C.
Published: October 2008

In Queensland it is standard practice to burn sugar cane before harvest, but incomplete burns are common, due to the lush condition of the crop and the occurrence of weeds. Experiments conducted over seven seasons to dry out foliage of both weeds and cane, using bipyridylium desiccants, showed that paraquat was consistently more effective than diquat. After treatment of cane foliage, several days were necessary for fully effective desiccation, during which time a slight drop in sugar content could usually be detected. It is practical to spray cane leaves in the outside rows, adjacent to headlands (where weeds normally thrive). Treatment of this peripheral zone could affect no more than 10 per cent of a cane stand, and any loss of sugar would usually be more than offset by the benefits of desiccation, viz: a cleaner burn, quicker cutting, less trash, and fewer penalties.
Use of Principal Component Analysis on Data from Chemical Analysis of Tea Leaves
Authors: Willson K. C. , Freeman G. H.
Published: October 2008

Univariate analyses of variance of mineral nutrient contents of samples of first and third leaves from seven fertilizer experiments in East Africa gave only limited information. Principal component analyses were then carried out on the nutrient contents of the third leaves. The most important component represented a balance between nitrogen and the basic nutrients potassium, calcium and magnesium, the variation of which was often related to yield. The results suggest that yield responses are likely to follow fertilizer applications only when the ratio of nitrogen to basic nutrients is within a defined range.
Soil Fertility Under Continuous Cultivation in Northern Nigeria. II. Responses to Fertilizers in the Absence of Organic Manures
Authors: Heathcote R. G. , Stockinger K. R.
Published: October 2008

Initial results of long-term trials in northern Nigeria indicate that deficiencies of potassium and trace elements, and soil acidity, may become important under continuous cultivation on some soils, in addition to the more common deficiencies of nitrogen and phosphorus.
Genetic Studies of Two Crosses ofBrassica CampestrisL.
Authors: Joarder O. I. , Eunus A. M.
Published: October 2008

Heritability of four quantitative characters in two crosses ofBrassica campestrisL. was found to be high. Dominance was detected only for plant height at heading time in both the crosses, and for sowing-to-heading period in Toria-TP × Toria-7. Transgressive segregation was expected in the segregating progenies for all the characters. Epistasis was complementary in all characters except in plant height at ripening time, where it was of the duplicate type. Additive × dominance type of epistasis was most significant and was present in most of the characters. Genes for most of the characters were linked with a major gene for seed colour (Rr). Yield was genetically correlated with the four quantitative characters studied.
Experiments on Maize and Groundnut using Micro-Plots
Authors: Walters D. E. , Yoon Chin Nyeok
Published: October 2008

The results are presented of an investigation into the use of very small plots for experimental work on maize (Zea mays) and groundnut (Arachis hypogaea), for the first three harvests of a project which is continuing. Despite the diminutive plot size, the random variation was quite low, resulting in a fairly sensitive experiment. The yield responses to increasing plant density were pronounced for both maize and groundnut, giving optimal spacings of 30 × 6 in. and 12 × 4 in. respectively.
Yields of Hybrid Sorghums
Authors: Doggett H.
Published: October 2008

Sorghum hybrids and varieties show similar responses to changing environment, with constant relative yield increases from the hybrids over a wide range of conditions due almost entirely to more florets and grains per plant and per hectare. Carbohydrate production of the leaves of good varieties is probably not much in excess of requirements for filling the grain. The extra spikelet number of the hybrid, increases in photosynthetic area and probably increased photosynthetic efficiency together enable the extra grains be filled. There is also an advantage in size and activity of the root system. The yield increase is strongly buffered against environmental fluctuations. The fact that hybrids can increase over a wide range of farming conditions should result in big increases in production simply by changing from varieties to hybrids, as is already happening in several countries.
Leaf Area and Yield in the Oil Palm in Malaya
Authors: Hardon J. J. , Williams C. N. , Watson I.
Published: October 2008

A method is described for estimating leaf area of the oil palm. Significant correlations were found between leaf area and yield in a number of progenies of palms growing in West Malaysia.
Evaluation of Fungicides for the Control of Helminthosporium heveae on Hevea Rubber in Malaysia I. Laboratory Assessment
Authors: Turner P. D.
Published: October 2008

To evaluate the potential efficacy of fungicides for the control of birds' eye spot in rubber nurseries, 49 formulations were tested in the laboratory by the paper disc diffusion and liquid culture methods. After discarding phytotoxic fungicides, only certain of the carbamate compounds, especially thiram, and those containing manganese and difolatan showed mazked activity in both series of tests. The results were compazed with field experience, and for the most part good correlations were found between laboratory and field results, a marked exception being the poor in vitro inhibition shown by zineb. A bimodal growth response was shown by the fungus to some of the carbamate formulations.
Evaluation of Fungicides for the Control of Helminthosporium heveae on Hevea Rubber in Malaysia II. Field Tests
Authors: Wastie R. L.
Published: October 2008

Nursery trials have shown that carbamate fungicides containing zinc or manganese are effective against Helminthosporium heveae. The addition of a wetting or sticking agent did not improve control, and in one test significantly reduced it.
Effects of Feeding Hay on the Early Wet Season Weight Loss of Cattle in Western Tanzania
Authors: Walker B.
Published: October 2008

At Ukiriguru, in Western Tanzania, cattle often lose weight appreciably in the first few weeks of the wet season. Three levels of supplementary hay feeding, compared over this period, showed initial effects, but the final weight differences between treatments were not significant due to the effects of later compensatory growth. Differences between treatments during the weight loss and compensatory growth phases can be mainly attributed to differences in dry matter intake, rather than differences in actual body weight.
Effects of Vacuum-Drying on the Viability of Oil Palm Pollen
Authors: Hardon J. J. , Davies M. D.
Published: October 2008

Pollen of the oil palm (Elaeis guineensis) was vacuum dried for various lengths of time and stored under vacuum in ampoules at 28°, 5° and −10°C. Little loss in viability over a period of 12 months was observed in any of the storage treatments when vacuum drying did not exceed one hour. Progenies resulting from crosses with pollen stored three months under vacuum have shown no anamolous seedling development.
Effects of Seed Bed Preparation and Time of Planting on Maize (Zea mays) in Western Nigeria
Authors: Lal Rattan
Published: October 2008

The variety Nigerian Synthetic-5 was sown on eight occasions, five in the first season and three in the second, at approximately 15-day intervals from 15 April to 15 June, and on 20 August, 4 September and 23 September. The method of seed bed preparation and time of planting both affected yields, effects that could be related to soil temperature and soil moisture reserve during crop development. Maize planted in August produced the highest yield; heaps and ridges gave the lowest yield at all planting dates, while planting on the flat or in furrows produced the highest yield.
Mass Selection of Commercial Hybrid Sugarcane Populations in Fiji
Authors: Brown A. H. D. , Daniels J.
Published: October 2008

The mass selection reservoir (MSR) is one way to take a population approach to the breeding of sugarcane. Yield data from four successive plantings of a sugarcane MSR showed consistent superiority to a commercial clone. The problem of defining satisfactory selection indices for the MSR is discussed.
Effects of Fertilizer Nitrogen on Yield of Wheat in Northern Sudan
Authors: Ahmed A. G. A. Gabar , Dafalla D. A.
Published: October 2008

An experiment at Hudeiba Research Station in Northern Province for three consecutive seasons, testing the effects of form, rate and time of application of nitrogen, showed that grain yield of wheat was significantly influenced by rate and time of application but two forms of fertilizers behaved similarly. None of the factors examined affected the 1000 grain weights. A second order polynomial function, fitted to yields at different nitrogen levels to determine economic levels was quadratic, best described by Y = a + 11·809x − 0·1037 x2. When almost all relevant factors were considered, 30–40 kg. of N per acre appeared to be an optimum economic level.
Improvement of Groundnut Pod-Filling by Lime and Gypsum Application to Some Soils in Northern Malawi
Authors: Laurence R. C. N.
Published: October 2008

Glasshouse and field trials have been used to assess the effect of applying calcitic lime and gypsum on haulm weight, pod-filling and kernel yield of groundnuts grown in soils of Northern Malawi. Incorporation of lime prior to planting and topdressing gypsum at flowering both rectified poor pod-filling and improved kernel yield. Gypsum decreased haulm weight and usually produced lower overall kernel yield than lime. The relative merits of lime and gypsum application are discussed, together with the need for supplementation by phosphorus and sulphur.
Genetic Studies in Sesame. II. Inheritance of Flower Colour and Number of Locules per Pod
Authors: Khidir M. Osman
Published: October 2008

A number of crosses were made to study the mode of inheritance of flower colour and number of locules per capsule of sesame. Red flower colour was dominant to white, and 4-loculed dominant over 8-loculed pods, each of the traits being controlled by a single gene pair segregating in a 3:1 F2 ratio.
Residual Effects of Unplanted Alleys in Rice Experimental Fields
Authors: Gomez Kwanchai A. , Duangratana Sanga
Published: October 2008

Researchers commonly use unplanted alleys to separate plots in experiments with paddy rice. In studies in the Philippines and Thailand we compared the performance of rice plants grown in previously cropped areas of a field with that of plants grown in areas which were unplanted alleys in the previous season. The latter plants had yields and values for several agronomic characters that were significantly different from plants grown in the previously planted areas, with yields ranging from 8 to 25 per cent higher.
The Interpretation of Regression Analysis and the Covariance Adjustment, with Particular Reference to Agricultural Research
Authors: Campbell N. A. , Goodchild N. A.
Published: October 2008

The aim of this paper is to help biologists gain a clearer understanding of what is involved in covariance analysis. It is an exposition on the derivation of the regression coefficient in the analysis of covariance, and hence on the interpretation of the covariance adjustment. The covariance adjustment is shown to be equivalent to regressing the residuals from an analysis of variance of the original variate on the residuals from an analysis of variance of the covariate.
Edge Effects and Interactions with Environment in Cocoa
Authors: Martin K. J. , Lockwood G.
Published: October 2008

In trials of seedling cocoa in Ghana, biases in the estimates of yield and tree size arising on the perimeters of experiments and on the interfaces of unguarded plots were strongly correlated, characteristic of progenies and stable across environments, but were inconsistent for black pod losses. No variate showed progeny × site interactions, but those of Caribbean yield data were interpreted by principal components analysis. The results show that 25-tree plots may be used for initial tests of new varieties and, as long as the environmental variation does not exceed that of the Ghanaian trials, at single sites.
Effects of Defoliation on Lodging and Yield of Maize Hybrids
Authors: Pinter L. , Kalman L.
Published: October 2008

Reducing the leaf areas of different maize hybrids at the time of female flowering resulted in a reduction of up to 70–90 g/plant of grain yield, with a parallel deterioration in the health of the stalk pith (due to infection by Fusarium sp.) and an increase in lodging. However, beyond a certain limit defoliation caused a loss in fertilization and a further decline in grain yield, which was accompanied by an improvement in the health of the pith and less lodging. There were considerable differences in the reactions of six genotypes to the defoliation treatments.
Variety × Environment Interactions in Western Nigeria Tomatoes
Authors: Adelana B. O. , Oyedokun J. B.
Published: October 2008

Ten tomato varieties, tested at three locations for 3 years in Western Nigeria, gave variety × environment interactions, indicating that some were only suitable for specific areas and none possessed wide adaptation. It is suggested that Western Nigeria could usefully be divided into sub-zones in which specific varieties could be developed.
Effects of Irrigation and Fertilizer on Mustard (Brassica juncea)
Authors: Joarder O. I. , Paul N. K. , Ghose S. K.
Published: October 2008

Three cultivars of mustard (B. juncea) were grown on field plots with five levels of fertilizers and with or without irrigation. Irrigation gave 59% more seed yield than no irrigation, accompanied by improved performance of ancillary characters. Significant increases in seed yield and most of the other characters were noted with increased levels of fertilizers, with a significant cultivar × fertilizer interaction due to the negative response of one cultivar to increased levels of fertilizers. The importance of irrigation and fertilizer in mustard seed production was thus demonstrated.
Calculators – How to Get the Answers Right
Authors: Ryder K.
Published: October 2008

Most scientists now own, or have access to, an electronic calculator and appear to have absolute faith in the answers it gives. However, these calculators have design limitations which for some data sets will affect the accuracy of the calculations and so produce incorrect results. In statistics work, corrected sums of squares and products, needed for Analyses of Variance and Regression Analyses, can be affected. The first two sections of this paper describe these limitations and illustrate how they can affect the result of calculating the variance of a particular data set. A simple procedure is then described that will help overcome the problem. Finally, in anticipaion that the micro-computer will eventually replace the calculator as the main mathematical tool, a more general procedure is given for calculating the sums of squares and products.
A Graphical Assessment of Data from Intercropping Factorial Experiments
Authors: Gilliver B. , Pearce S. C.
Published: October 2008

A graphical method, based on bivariate analysis, is used to present yield data from intercropping experiments involving two crop species. The method is used to demonstrate two- and three-factor interactions in factorial experiments.
Effects of Harvesting Policy and Nitrogen Application Rates on the Production of Tea in Central Africa. II. Quality and Total Value of the Crop
Authors: Cloughley J. B.
Published: October 2008

The black teas produced from the field treatments described previously (Cloughley et al., 1983) were evaluated chemically and organoleptically. Increasing N application rates and harvesting larger shoots had adverse effects on the liquor quality as assessed by theaflavin (TF) analysis, and on the value of the product as assessed by tea tasters' sensory examination. There were also large, regular intraseasonal fluctuations in TF content, small values corresponding to occasions of crop peaks. Shoots predominantly of 2 or 3 leaves and a bud harvested from plots given 135 kg N ha−1 generated the largest total cash value. A total value index (TVI), involving yield and quality, is introduced and illustrated.
Effect of the Germinating Seed Environment on Crop Yields. I. Effect of Soil Acidity at Germination on Yields of Sweet Clover and Alfalfa
Authors: Haller E.
Published: October 2008

The dependence of yields of sweet clover and alfalfa on environmental conditions, including soil acidity, at the germination stage has been studied over a period of 28 years. Results have been dramatic: sweet clover and alfalfa can grow well and produce large yields even on strongly acid soils (pHKCl 4.0) providing that the process of germination starts in a neutral medium.
Effects of Genotype in Cereal/Pigeonpea Intercropping on the Alfisols of the Semi-Arid Tropics of India
Authors: Rao M. R. , Willey R. W.
Published: October 2008

In a 2 row cereal: 1 row pigeonpea intercropping system, four sorghum and two millet genotypes were examined with four of pigeonpea on a medium-deep Alfisol during 1978 and 1979. The cereals usually produced a large proportion of their sole crop yields. Millets matured relatively early which allowed large yields of later-maturing pigeonpea. A tall millet gave the best total Land Equivalent Ratio (LER) of 1.78 and most monetary returns. Early and/or short sorghums produced large LERs (1.51–1.59) and combinations with an early hybrid also gave good returns. A tall late sorghum gave poor yields of both components, smallest total LER (1.30), and little return. Pigeonpea intercrop yields became larger as the maturity difference between the cereal and pigeonpea increased. A combination of a short, early but large-yielding cereal with a pigeonpea that is as late as possible without incurring undue risk of moisture stress may be ideal.
Effect of Intercropping on Nodulation and N2-fixation by Groundnut
Authors: Nambiar P. T. C. , Rao M. R. , Reddy M. S. , Floyd C. N. , Dart P. J. , Willey R. W.
Published: October 2008

Nodulation and N2-fixation of groundnut were investigated in sole and intercropping systems. Intercropping with pearl millet, maize, or sorghum reduced nodulation and N2-fixation. This effect is ascribed to the shading of groundnut by the cereal component and the consequent decrease in photosynthesis of the legume canopy.
Effects of Cultural Practices on Growth, Yield and Economics of Fibre Flax Production in the North Western Himalayas
Authors: Guleria W. S. , Singh C. M.
Published: October 2008

Field experiments investigated the effects of seed rate, row spacing and time of harveston growth and yield of irrigated fibre flax and economics of fibre production at the Experimental Farm, Palampur, North Western Himalayas during two winter seasons between 1979and 1981. A seed rate of 60 kg ha−1 and row spacing of 20 cm gave the best yield and most profit. Any delay in harvesting after flower initiation significantlyincreased fibre yield and net profit per hectare.
Nitrogen Uptake of Field-grown Cotton. I. Distribution in Plant Components in Relation to Fertilization and Yield
Authors: Oosterhuis D. M. , Chipamaunga J. , Bate G. C.
Published: October 2008

Three levels of nitrogen (N) were applied to cotton grown in irrigated field trials at two locations in Zimbabwe in 1978. Dry matter (DM) production, total uptake and distribution of N among vegetative and reproductive components, and soil mineral-N contents were recorded about every 14 days. About 60% of total DM was produced, and 40% of total N taken up, between 10 and 16 weeks after sowing. Most N was present in vegetative parts, particularly leaves and branches, during early growth but, later, it accumulated in buds, flowers and bolls. At maturity, seeds and lint contained 42% of total above-ground plant N. N concentrations were similar in sympodial and mainstem leaves, petioles and branches. Inorganic N applied at sowing had little effect on plant N, but when given after 10 weeks it increased the N content of leaves, stems, branches, petioles and bolls.
Nitrogen Uptake of Field-grown Cotton. II. Nitrate Reductase Activity and Petiole Nitrate Concentration as Indicators of Plant Nitrogen Status
Authors: Oosterhuis D. M. , Bate G. C.
Published: October 2008

The possibility of using seasonal changes in leaf nitrate reductase activity (NRA) as a reliable and sensitive indicator of plant nitrogen (N) status has been investigated in field-grown cotton. These changes were compared with those in nitrate concentration in petioles and variations in soil-N concentration. We conclude that NRA in the uppermost, fully-expanded sympodial leaves may provide a more convenient, sensitive and reliable indicator of plant-N status than measurements of nitrate concentrations in petioles.
Preliminary Studies of Intercropping Combinations Based on Pigeonpea or Sorghum
Authors: Rao M. R. , Willey R. W.
Published: October 2008

Various intercrops were examined in an alternate row pattern with pigeonpea or sorghum on both Alfisol (red soil) and Vertisol (black soil). The slow-establishing and later-maturing pigeonpea combined well with earlier cereals and legumes to give very large yield advantages as measured by the Land Equivalent Ratio. In the pigeonpea/cereal combinations, the earlier the cereal the bigger the yield advantage tended to be, attributed to improved use of resources over time as the difference in maturity periods of the component crops increased. Sorghum was generally more competitive than pigeonpea and intercropping advantages tended to be less. But even where there was little difference in maturity periods of the component crops, both sorghum/legume and sorghum/cereal combinations gave substantial and statistically significant advantages, suggesting that improved ‘spatial’ use of resources was also important.
Dry-season Legume Forages to Follow Paddy Rice in N.E. Thailand. I. Species Evaluation and Effectiveness of Native Rhizobium for Nitrogen Fixation
Authors: Shelton H. M.
Published: October 2008

A range of legumes was evaluated in North-east Thailand for dry season forage production on stored moisture following harvest of the paddy rice crop. Crotalaria juncea (sunnhemp) and Lablab purpureus (lablab) produced the best dry matter yields of 1950 and 2020 kg−1 ha respectively on a cultivated paddy field without further fertilizer. Stored moisture was adequate for these two but growth of other species was poor, especially on plots that received no prior cultivation. In pot experiments, sunnhemp did not respond to either nitrogen application or Rhizobium inoculation, indicating that native strains were effective for nitrogen fixation. Lablab responded to both treatments and gave a 55% dry matter response to inoculation with Rhizobium in the field.
Effects of Macronutrients and Cutting on Mulberry Cultivars in Malaysian Peat
Authors: Chew W. Y. , Joseph K. T. , Adam M. A. , Ramli K. , Zulkifly A. K.
Published: October 2008

N, P and K fertilizers improved mulberry leaf, stem and fruit yields on peat, the optimum rates being 100 kg/ha/yr N, 25 kg P and 62·5 kg K, with further leaf responses to N and K if applied together in the ratio of 3:2. Harvesting every 2 months at 60 cm height gave better yearly leaf yields than cuttings 3–12 months apart, but annual stem yields were not affected by harvesting frequency and fruit yields were optimum when plants were cut at intervals of 5–6 months. Harvesting quarterly at 60 cm produced better leaf and stem yields than cutting lower (15 and 30 cm) or higher (100 and 180 cm). Two Thai cvs (Noi I and Mii) were female-sterile but the Local Malaysian produced fruits.
Evaluating Technical Innovations under Low-resource Farmer Conditions
Authors: Flinn J. C. , Lagemann J.
Published: October 2008

Before an innovation can be judged as superior to existing technology, its relevance should be jointly evaluated by researchers and farmers by testing the proposed practice in a farm environment. Using a proposed maize technology as an example, it is demonstrated how site-related and management variables can be used to quantify the factors influencing actual yields on farmers' fields. Similarly, economic and management analysis of the practice provides an estimate of the probability of the farmer being better off by using the technology. The integrated analysis of the practice provide insights for the design of problem-oriented research projects.
Nitrate Assimilation in Relation to Total Reduced N in Bengal Gram (Cicer arietinum)
Authors: Pokhriyal T. C. , Abrol Y. P.
Published: October 2008

On the basis of a preliminary experiment with 20-day-old Cicer seedlings, wherein the values obtained by integrating the in vivo nitrate reductase (NR) activity with the duration closely approximated the actual reduced N, a field experiment was conducted with cv BG 203 (indeterminate type) to ascertain the extent to which the nitrate assimilated via the enzyme NR contributed to the total reduced N. Soil-derived N accounted for 15.1, 8.3 and 7.2% of the total reduced N at pre-flowering (I), profuse flowering (II) and seed filling (III) stages respectively. Out of the total soil-derived N, 10.1, 59.3 and 30.6% was reduced during stages I, II and III respectively.