bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genotype Effects in Millet/Cowpea Intercropping in the Semi-arid Tropics of Niger
Authors: Reddy K. C. , van der Ploeg J. , Maga I. 
Published: October 2008

SUMMARYThree pearl millet and three cowpea genotypes were examined in intercropping systems on deep sandy soils in Niger between 1984 and 1987. The intercropped pearl millet genotypes usually produced at least 80% of their sole crop yields when the cowpea was planted two or more weeks after the pearl millet. The early maturing and spreading cowpea genotype contributed most to LER. All cowpea genotypes yielded more when planted in association with dwarf rather than the traditional tall pearl millet genotypes because they received more light.
The Effect of Photoperiod on the Reproductive Development of a Photoperiod Sensitive Groundnut (Arachis hypogaea L.) Cv. NC Ac 17090
Authors: Flohr Marie-Luise , Williams J. H. , Lenz F. 
Published: October 2008

SUMMARYThe physiological basis for responses to daylength of a photoperiod sensitive groundnut genotype (NC Ac 17090) was investigated by comparing its growth and development in natural daylength with that in an artificially manipulated photoperiod in three field experiments. Photoperiod did not influence the thermal time to flowering, or the subsequent appearance of flowers until 900–950 flowers m−2 had appeared. Thereafter flowers continued to appear in short, but not in long, days. In each experiment, long days increased the thermal time between the initiation of each peg and pod, and the thermal time required for each fruit to mature. These fruit initiation and developmental changes were reflected in the partitioning of assimilates to pods, this being substantially less in long days than in short. Changes in pod initiation rate, partitioning co-efficient, and the thermal time taken for a pod to mature were related to mean daylength.
Effects of Intercropping Oilseeds and Pulses in Roselle (Hibiscus sabdariffa)
Authors: Roy A. R. , Sasmal B. C. , Bhattacharjee A. K. 
Published: October 2008

SUMMARYThe effects of intercropping roselle with blackgram, cowpea, soyabean, groundnut and sesame under single, double and triple row planting patterns and at three different intercrop sowing dates were studied from 1983 to 1985. The fibre yield of roselle was reduced by intercropping. The reduction was least with groundnut and greatest with cowpea but was compensated for by the yield of the intercrops. Double and triple row planting systems favoured the productivity of both roselle and the intercrops, increasing the Land Equivalent Ratio (LER) of the cropping system. The best yields of roselle were obtained when the intercrops were sown 15 days after the roselle.
Light Use, Water Uptake and Performance of Individual Components of a Sorghum/Groundnut Intercrop
Authors: Azam-Ali S. N. , Matthews R. B. , Williams J. H. , Peacock J. M. 
Published: October 2008

SUMMARYThe productivity of each component of a sorghum/groundnut intercrop and its constituent sole crops is determined in terms of a ‘Crop Performance Ratio’ (CPR) defined as the productivity of an intercrop per unit area of ground compared with that expected from sole crops sown in the same proportions. The CPR allows productivity, intercepted radiation and seasonal transpiration to be compared so that conversion coefficients for radiation (e; g MJ−1) and dry matter/water ratios (q; g kg−1) can be calculated for each intercrop component and its constituent sole crops. In this experiment, CPR for total dry weight in the intercrop was 1.08 and that for reproductive yield was 1.27. These advantages in overall productivity and yield were typical of those reported elsewhere for sorghum/groundnut intercrops. The proportional increase in total dry matter in the intercrop was largely a result of its greater interception of radiation. The further advantage in reproductive yield was a consequence of an improved harvest index in the sorghum component of the intercrop (0.64) compared with that of its sole crop counterpart (0.55).
Simulation of the Seed Bank Dynamics of Orobanche crenata Forsk. in some Crop Rotations Common in Northern Syria
Authors: Schnell H. , Kunisch M. , Saxena M. C. , Sauerborn J. 
Published: October 2008

SUMMARYSimulations of the dynamics of the seed bank of Orobanche crenata Forsk. under different crop rotations are presented. Rotations studied involved four host species, lentil (Lens culinaris Medik.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.) and woolly-pod vetch (Vicia villosa subsp. dasycarpa (Ten.) Cavill.), and non-host species. Simulation showed that the Orobanche seed bank dynamics in three-course crop rotations would result in a high Orobanche seed population and hence in low yields of the respective crops. Replacing the susceptible by resistant legumes such as woolly-pod vetch in some of the cycles of the rotations would keep the Orobanche infestation at a low level without reducing the proportion of legumes. A three-course crop rotation with faba bean would have to be changed to a 12-coursc rotation in which faba bean was grown every twelfth year but was replaced by woolly-pod vetch or other resistant legumes in seasons 3, 6, 9; 15, 18, 21; and so on. In the three-course rotations with chickpea or lentil, these susceptible legumes would be grown every ninth year but would have to be replaced in seasons 3 and 6; 12 and 15; 21 and 24; and so on, thus changing these three-course rotations into nine-course rotations.
Optimization of Mineral Nutrition in a Coconut Plantation Taking an Experimental Approach in situ
Authors: Bonneau X. 
Published: October 2008

SUMMARYOver several decades agronomists have developed a mineral nutrition management method for perennial oil crops based on leaf analysis combined with reference field trials. This method has been used in a coconut plantation on the peats of the east coast of Sumatra to optimize mineral nutrition in a very short time, at minimum cost and with maximum reliability, through successive adjustments of the fertilizer schedules. Two reference trials were set up to study a wide range of mineral nutrients assumed to be deficient on this area. Further experiments were set up as new nutritional problems occurred at the plantation, and as soon as the first results were obtained from these two trials. In this way, the iron and copper deficiency problems at the plantation were dealt with satisfactorily taking an experimental approach. New experiments were set up recently to test the hypothesis of a silicon deficiency. The fertilization schedules for the commercial plantation were developed by successive adjustments based on the trial results. Leaf analysis data showed that the coconut palms in the commercial plots always complied with the experimental models. In addition to being rapid and reliable, this method was also cost-effective, especially when larger areas were involved.
Production of Seedling Tubers Derived from True Potato Seed and Their Use as Seed Tubers in the Sudan
Authors: El-Amin S. M. , Adam B. , Varis E. , Pehu E. 
Published: October 2008

SUMMARYSeedling tubers of three true potato seed (TPS) crosses raised in a seedbed soil mixture of clay, sand and dry leaves produced about 3.1 kg of seedling tubers m−2 in the growing season of 1988–89 and between 4.3 and 5.1 kg m−2 in 1989/90. The seedling tubers produced were stored and their use as seed tubers was subsequently compared with the locally popular variety Alpha. The mean tuber yields of the hybrids ranged between 9.4 and 11 t ha−1 in 1990/91 and between 21.9 and 22.9 t ha−1 in 1991/92. Mean tuber yields of cultivar Alpha were 14.3 t ha−1 in 1990/91 and 24.1 t ha−1 in 1991/92, showing that tuber yields comparable to those of imported seed tubers could be obtained from seedling tubers of TPS origin.
Long-term Comparison of the Agronomic Efficiency and Residual Benefits of Organic and Inorganic Nitrogen Sources for Tropical Lowland Rice
Authors: Cassman K. G. , de Datta S. K. , Amarante S. T. , Liboon S. P. , Samson M. I. , Dizon M. A. 
Published: October 2008

SUMMARYNitrogen efficiency fromAzolla microphyllaorSesbania rostratagreen manure, rice straw, and inorganic fertilizer-N was compared in two long-term experiments with irrigated lowland rice (Oryza sativaL.). Treatments included a control and each nitrogen source alone or in combinations that provided 50% of the total applied nitrogen from an organic and inorganic nitrogen source. All nitrogen sources were applied at equivalent nitrogen rates to 19–22 consecutive rice crops. Residual effects were assessed in two subsequent cropping seasons at one site. Lower grain yield, agronomic efficiency (Δgrain per kg total applied nitrogen), and apparent nitrogen uptake were obtained from green manure and rice straw nitrogen as sole or dual nitrogen sources rather than from a standard split application of prilled urea. Compared to prilled urea, residual effects from green manure or rice straw included a significant increase in soil organic carbon and total nitrogen, and greater extractable soil nitrogen in the vegetative growth period. After panicle initiation there was no residual effect on the rate of crop nitrogen accumulation, and final grain yields were similar regardless of previous nitrogen source. Recycling of rice straw appeared to have greater potential for reducing fertilizer-N requirements than use of green manure because rice straw is often a wasted resource in irrigated rice systems of the humid tropics, the efficiency of rice straw nitrogen in combination with prilled urea is comparable to green manure nitrogen, and the increase in soil nitrogen from rice straw was 50–150% greater than from green manure.
The Photosynthesis and Transpiration of Crops
Authors: Monteith J. L. 
Published: October 2008

SummaryWhen a leaf absorbs radiant energy, only a small fraction is stored chemically in photosynthesis. In sunlight, this fraction is at most one-fifth of the energy in the visible spectrum, decreasing with increasing light intensity because of the finite resistance to the diffusion of carbon dioxide through the leaf to the chloroplasts. Energy absorbed but not stored in photosynthesis is dissipated by transpiration and convection.The potential or maximum photosynthesis of a crop canopy can be estimated from a set of six parameters describing the photosynthesis-light curve of single leaves, the arrangement of leaves in the canopy, and radiation climate. Comparing estimates of potential photosynthesis with measurements of carbon dioxide exchange over a field of sugar beet, the estimated rate of respiration was 2 gm carbohydrate per m2 leaf area per day, equivalent to 44 per cent of gross photosynthesis over the whole growing season. Over the season, the foliage lost 34 per cent of incident radiation by transmission to the soil.The potential rate of transpiration can be found from Penman's formula assuming values of external (aerodynamic) and internal (mainly stomatal) resistance for the canopy as a whole. In south-east England, the energy for potential transpiration is almost equal to net heat H in summer and is therefore about half the energy of incoming solar radiation. For a real crop of grass subject to moisture stress, transpiration was less than the potential rate at about 0·8 H on average and 0·3 H in very dry weather.During the summer, cumulative photosynthesis increases linearly with cumulative transpiration to give a production ratio (gross photosynthesis/transpiration) of 1/100 in the Thames Valley and 1/200 in the Sacramento Valley. The production ratio is expected to change with crop type as well as with climate.
Effect of Planting-Date on Nodulation and Dry-matter Yield of Cowpea in Nigeria
Authors: Tewari G. P. 
Published: October 2008

SummaryA split-plot field experiment was conducted to investigate the influence of planting dates on the formation of nodules in a variety of cowpea (Paraguay 6). Results indicated that the principal factor influencing both nodulation and yield was day-length, the highest number of effective nodules being produced from the June planting.
The Influence of Plant Density on the Morphological Characters and Seed Production of Common Vetch (Vicia sativa L.)
Authors: Blum A. 
Published: October 2008

SummaryPlant population studies were carried out in 1963 and 1964, including row spacing of 75 cm at different within-row densities, for purposes of comparison with the common practice of drilling at 15 cm spacing. Planting in spaced rows 75 cm apart, with increasing intra-row density from 55 to 175 seeds per metre of row, increased seed yield compared with drilling and a high intra-row density was better than low intra-row density for seed yield. The increase in seed yield was due to a higher number of stems, flowers and pods per unit area, and to a higher number of flowers forming mature pods. Seed set was better in spaced rows than at drill-spacing. Flowering took place over a shorter period, and the peak was attained earlier, at higher within-row density. Plant competition influenced plant branching as early as sixteen days after emergence. The relation between seedling development and seed yield is discussed.
Irrigation Frequencies for Lucerne on Shallow Granite Sand in Low Rainfall Areas of Rhodesia
Authors: Landsberg J. J. 
Published: October 2008

SummaryMature lucerne on shallow granite sand was irrigated at different intervals, determined by four factors, 0·4, 0·6, 0·8 and 1·0, applied to daily evaporation (E0) as measured by a USWB Class A pan. Moisture balances were calculated for each treatment, and when the accumulated sum of daily evaporation, multiplied by the appropriate factor, reached 1·2 inches, which was about 50 per cent of the available moisture in the top 2 feet of soil, this amount of water was applied to the plots of the treatment concerned. Irrigation on the basis of 0·8 E0 gave the but overall results, although the highest yield from a single cut was obtained with the irrigation frequency defined by 1·0 E0. During the rainy season yields from all treatments declined markedly, those from the most frequently irrigated treatment showing the greatest drop. The lucerne under the irrigation regimes defined by 0·4 and 0·6 E0, although subjected to considerable moisture stress in the dry weather, suffered no lasting ill effects and yielded well during the rains. The experimental area was almost certainly subject to advective energy but the results are considered valid for local conditions.
Agronomic Factors Influencing Yield and Quality of Groundnuts in the Sudan Gezira
Authors: Tahir W. M. , Misovic M. S. 
Published: October 2008

SummaryAn early upright-bunch variety of groundnut, Barberton, and a medium-late spreading-bunch variety, Ashford, were compared at 7·5, 15·0 and 30·0 cm. intra-row spacings planted at one and two kernels per hill on 60 cm. ridges in the irrigated heavy clay soil of the Sudan Gezira in 1963 and 1964. Barberton was harvested on days 95, 110 and 125, and Ashford on days 125, 140 and 155 after planting in July–August. Ashford outyielded Barberton at the lower densities, and the best pod yields were obtained on day 125 harvest at a population of 55,000–60,000 plants per acre. A higher plant population depressed the yield of Ashford while the increased pod yield of Barberton was not significant. Field germination of kernels increased more in Barberton with delay in harvest and with decrease in plant population than in Ashford. Mean pod and kernel weights and shelling out-turn of Barberton increased with delay in harvest. Barberton gave higher oil content and shelling out-turn, and lower proportion of pods with single kernels than Ashford. The highest population of Barberton gave the best oil content in early harvests. In general, the arrangement of plants within rows at similar populations had only small effects except on the quality of nuts, which was improved by planting single kernels at close spacing (7·5 cm.) with the variety Barberton and two kernels at wide spacing (15·0 cm.) with Ashford, at optimum plant populations.
A Note on the Grafting and Anatomy of Black Pepper
Authors: Garner R. J. , Beakbane A. Beryl 
Published: October 2008

SummarySome early attempts to graft black pepper are described. Good unions have formed between different clones of Piper nigrum L., and between different species of Piper grown in a glasshouse in the United Kingdom. The structure of pepper stems is considered in relation to the apparent impermanence, in the tropics, of unions that initially appear to be successful.
The Potential Availability of Organic Nitrogen Fractions in Some West Indian Soils
Authors: Cornforth I. S. 
Published: October 2008

SummaryThe effect of four crops of maize on the distribution of organic nitrogen in ten West Indian soils, given either lime, P, K, Mg and trace elements or no fertilizers, was studied in a greenhouse experiment. The soils were also analysed for ‘available N’ by incubation and chemical methods. Variations in the redistribution of organic N fractions during the greenhouse experiment did not permit conclusions to be drawn on the source of N used by the maize, although the amount of hydrolysable N, particularly hexosamine, amino and hydroxy-amino N, in the initial samples was closely related to N uptake. Part of the chemically stable, non-hydrolysable organic N was broken down by soil organisms during the experiment; this was increased by liming acid soils.
Effects of Rhizobium-Inoculum Placement on Peanut Inoculation
Authors: Schiffmann J. , Alper Y. 
Published: October 2008

SummaryAn experiment was conducted on peanut inoculation with Rhizobium inoculum, introduced below the planting level at three different soil depths (8, 12 and 15 cm.), to ensure more favourable moisture conditions for proliferation of the root nodule bacteria, and to obviate the need for frequent irrigation. Inoculation on both sides of the peanut rows, after the plants had emerged, was also tested. The number and weight of nodules per plant decreased with increase in placement depth. Side inoculation after emergence of the plants resulted in significantly less plant infection than placement of the inoculum at 8 and 12 cm. depths. Peanut yield and quality after inoculation at 15 cm. depth were significantly lower than at 8 cm. inoculation.
Inoculation of Peanuts by Application of Rhizobium Suspension into the Planting Furrows
Authors: Schiffmann J. , Alper Y. 
Published: October 2008

SummarySoil inoculation was tried in field experiments during two seasons using different concentrations and amounts of bacterial suspension and compared with direct seed inoculation of chemically protected and unprotected peanut seed. Soil inoculation gave significantly better results than direct inoculation of chemically protected or unprotected seed.Large yields of high quality peanuts, which compared favourably with highly nitrogen-fertilized peanuts, were obtained after the application of relatively small amounts (10–40 gm.) of enriched peat inoculant in 5 litres of water per dunam (1/10 ha).
Nodulation of Tropical Legumes I. Specificity in the Rhizobium Symbiosis of Leucaena leucocephala
Authors: Trinick M. J. 
Published: October 2008

SummaryLeucaena leucocephala (Lam.) de Wit. failed to nodulate with 94 of the 99 strains of Rhizobium tested, representing the seven recognized cross-inoculation groups of nodule bacteria. A group of legumes including L. leucocephala, Mimosa invisa Mart., M. pudica L., Acacia farnesiana (L.) Willd. and Sesbania spp. showed the properties of a cross-inoculation group of plants. Rhizobia isolated from these legumes were all fast-growers and nodulate L. leucocephala, often effectively, and also many other tropical legumes, including Vigna sinensis (L.) Savi ex Hassk., which are usually nodulated effectively with slow-growing root-nodule bacteria. The taxonomic significance of the results is discussed.
Timing and Frequency of Spraying for Control of Coffee Leaf Rust in Southern India
Authors: Ananth K. C. 
Published: October 2008

SummaryTo study control of Hemileia vastatrix leaf disease in Coffea arabica L., an experiment was run for a year in Coorg District of Mysore State. Three and four early-season sprays coupled with two mid-season ones gave a reasonable control, as evaluated by leaf spot counts, but a high proportion of rust-affected leaves were retained on the bushes. Infection commenced in the hot weather, immediately after showers, and the number of infected leaves appears to have been more important than the average leaf spot counts. Control of leaf disease up to December, and a late incidence of the rust during January, may not affect crop prospects appreciably. It is suggested that reduced early sprays coupled with pre-monsoon and timely mid-season schedules should reasonably control the incidence of rust.
Effects of Moisture and Nitrogen on Growth, Yield and Mineral Content of Rice
Authors: Pande H. K. , Singh Panjab 
Published: October 2008

SummaryLimited moisture supply caused reduction in leaf area, number of effective tillers, ratio of sound to unsound grains and the nitrogen, phosphorus, iron and manganese content of rice. Crop yield was adversely affected in the absence of standing water. Two levels of nitrogen (40 and 60 kg.N/ha.) caused no significant difference in yield in 1965, but in 1966, when 30 and 60 kg. N/ha. were used, the latter gave better yields.
Fertilizer Responses by Coconuts (Cocos nucifera) on Two Contrasting Jamaican Soils
Authors: Smith R. W. 
Published: October 2008

SummaryThe results from a 33 and two 25 factorial fertilizer experiments are presented. N-deficiency limited female flower production, rate of bunch production, and yield; K-deficiency reduced the setting of flowers and yield; nuts were larger where P was applied. The results are interpreted in the light of foliar analyses, and the concept of independant critical levels of the major nutrients is challenged. It is suggested that yield is related to the ratios between foliar N and K, but that the K level should in turn be interpreted in the light of a balance between the monovalent and divalent cations. Female flower production and setting can be used as a ready field guide to nutrient requirements.
Effects of Planting Date and Spacing on Yields of Onion Seed under Hot Arid Conditions in the Sudan
Authors: Abdalla Abdalla Ahmed 
Published: October 2008

SummaryExperiments in two successive seasons showed that planting date and spacing of bulbs affected the seed yield of Sudanese onions, but not the number of branches and seed heads produced by bulbs. Yield per plant increased with increase in spacing, but closer spacing gave the highest yield per unit area. Later sowing depressed seed size, weight and yield.
Component Analysis: An Aid to the Interpretation of Data
Authors: Holland D. A. 
Published: October 2008

SummaryPrincipal component analysis is a mathematical technique for summarizing a set of related measurements as a set of derived variates, frequently fewer in number, which are definable as independent linear functions of the original measurements. Consideration of their mathematical nature shows that they do not, themselves, necessarily correspond to sensible biological concepts, though they are more amenable to statistical study than the original measurements. Further, by assessing the extent to which they are in accordance with biological hypotheses, or with the results of other, similar, analyses, they can be transformed into other linear functions which are meaningful in the biological sense, or consistent with other results. Thus the specific technique of principal component analysis is developed into a more general component analysis approach. With proper regard for the purpose the analysis is intended to serve and for the mathematical restrictions involved, this approach can lead to a useful condensation of a mass of data, a better under-standing of the observed individuals as entities rather than collections of isolated measurements, and to the formulation of new hypotheses for subsequent examination.