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Establishing optimum plant populations and water use of an ultra fast maize hybrid (Zea Mays L.) under irrigation
No full textEnglish: For each grain production system, there is an optimum row spacing and plant density that optimises the use of available resources, allowing the expression of maximum attainable grain yield in that specific environment. Introduction of the ultra-fast maize hybrids raised the question whether existing guidelines for row spacing and plant density were still applicable. This necessitated the integration of optimum row spacing by plant density to maintain productivity and sustainability the yields with the intention to increase water use efficiency. Field experiments were conducted for two successive cropping seasons (2008/9 to 2009/10) at Kenilworth Experimental Station of the Department of Soil, Crop and Climate Sciences, University of the Free State to evaluate the growth, agronomic performance, phenological development and water use efficiency of an ultra-fast maize hybrid at varying row spacing and plant densities under irrigation. The treatments involved in this study were three row spacings (0.225, 0.45 and 0.90 m) and five plant densities (50 000, 75 000, 100 000, 125 000 and 150 000 plant ha-1). The treatments were arranged in a factorial combination and laid out in a randomized complete block design (RCBD) with four replications. The largest block was used for periodic destructive sampling for growth analysis where a completely randomized design was adopted and replications consisted of five (5) single plants randomly selected. Regarding soil water monitoring, twenty neutron probe access tubes were installed prior to planting in the center of each plot in one of the three blocks of the agronomic study. Soil water content was measured at 0.3 m intervals to a depth of 1.8 m using a calibrated neutron probe. Measurements were made at weekly intervals from planting to crop physiological maturity where the volumetric reading was converted into depth of water per 1.8 m. Seasonal ET (water use) was determined by solving the ET components of the water balance equation. From this water use efficiency was computed as the ratio of total biomass/grain yield to seasonal ET. In each season crop growth, agronomic, phenologic and water use efficiency parameters were measured and the collected data were combined over seasons after carrying the homogeneity test of variances. Growth parameters, agronomic traits, phenology and water use efficiency of maize reacted differently to row spacing and plant density and the combination thereof. In general a slow increase in growth parameters during establishment was followed by an exponential increase during the vegetative phase. At the reproductive phase growth ceased following the onset of flowering. Photosynthetic efficiency (NAR) and CGR, averaged over row spacing, were highest at a plant density of 100 000 plants ha-1 at all growth phases. Reducing row spacing from 0.45 to 0.225 m and a plant density below or above 100 000 plants ha-1 showed LAI outside the optimum with respect to NAR for optimum seed yield. Row spacing, plant density and its interaction affected yield and yield components of maize significantly. Narrowing rows from 0.45 to 0.225 m and plant densities above 100 000 plants ha-1 as main or interaction effects led to the formation of smaller ears, a shorter ear length and diameter, low seed mass, favored plant lodging and development of barren plants with an obvious negative impact on grain yield. On other hand, plant densities below 100 000 plants ha-1 were insufficient to utilise growth-influencing factors optimally. Thus, growth analysis provided an opportunity to monitor the main effects and interaction effects of row spacing and plant density on crop growth at different growth and development phases. Row spacing and plant density combinations affected the phenological development of maize. Increasing row spacing from 0.225 to 0.90 m relatively prolonged the number of days to anthesis and silking. Regarding anthesis-silking interval (ASI), the lowest plant density had the shortest ASI while the higher plant densities had relatively longer ASI. Wide row spacing coupled with low plant density increased the number of days to physiological maturity and vice versa. Row spacing and plant density and their interaction affected water use efficiency of maize. Highest water use was observed at a plant density of 125 000 plants ha-1. Biomass WUE was highest at a row spacing of 0.45 m with a plant density of 125 000 plants ha-1 while the highest grain yield WUE recorded was at a row spacing of 0.45 m with a plant density of 100 000 plants ha-1. The overall combined effect of row spacing and plant density revealed that a combination of 0.45 or 0.90 m with 100 000 plants ha-1 to be the optimum for the selected ultra-fast maize hybrid under irrigation.Rural Capacity Building Project (RCBP
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Response of haricot bean (Phaseolus vulgaris L.) to row spacing and weeding frequencies in Wolaita Zone, Southern Ethiopia
Get PDFThe common bean is the most important legume in Ethiopia for export and as a source of protein. Weed infestation and lack of appropriate row spacing are major factors affecting its growth and yield. However, limited research exists to determine proper weed management and optimum row spacing for improving the yield performance of haricot beans. Therefore, a field experiment was conducted in the Wolaita Zone, southern Ethiopia, to evaluate the influences of variable row spacing and hand-weeding frequencies on the growth and yield of common bean. Treatments consisting of three-row spacing and five weeding frequencies were laid out in a randomized complete block design in a factorial arrangement with three replications. Data on phenology, growth, yield components, seed yield, and weed parameters were collected and analyzed procedurally. The result showed that weeding frequencies had a significant (p < 0.05) effect on days to flowering, days to physiological maturity, plant height, leaf area, leaf area index, pod number, seed number, hundred seed weight, total above-ground biomass, grain yield, weed population, weed dry weight, weed control efficiency, and yield loss, while row spacing had a significant effect on leaf area, leaf area index, pod and seed number, grain yield, total aboveground biomass yield, and yield loss. On the other hand, the interaction effect was shown to be significantly different in the weed population only. Three times of hand weeding and the recommended row spacing of 40 cm resulted in the highest grain yields of 2549.6 kg ha-1, 2056 kg ha-1, respectively. The highest net benefit (15415.56 ETB ha-1) was recorded from hand weeding done three times, and the highest marginal rate of return (209.99) was obtained from hand weeding done two times. As a result, for greater economic benefit from haricot bean production in the studied area, twice-hand weeding after two and four weeks of crop emergence with a row spacing of 40cm could be recommended
Effect of Blended Nitrogen, Phosphorus, Sulfur, Boron, and Potassium Fertilizer Rates on Growth and Yield of Maize (Zea mays L.) at Sodo Zuriya District, Southern Ethiopia
No full textThere are various challenges that limit crop productivity in developing countries like Ethiopia. Lack of accessible plant nutrients in proper quantity as well as form to plants is an important determinant of reducing agricultural productivity. In this regard, a trial was conducted at Shela Borkoshe on the land owned by the farmer in Sodo Zuriya District, Wolaita Zone, Southern Ethiopia over the planting seasons of 2019 to 2020 with the aim of identifying the appropriate rates of blended nitrogen, phosphorus, sulfur, boron (NPSB), and potassium (K) fertilizer in maize production. The treatments, which were assessed using a factorial randomized complete block design with three replications, comprised of four rates of blended NPSB (0, 50, 100, and 150 kilograms/hectare) and four rates of K (0, 30, 60, and 90 kilograms/hectare K2O). Agronomic traits leaf area, LAI, ear length, seeds per row, seeds per ear, TSW, biomass as well as grain produce have been significantly varied due to NPSB by K fertilizer rates interactions. The highest leaf area (9886.20 ± 343.95 cm2), LAI (7.78 ± 0.26), ear length (32.58 ± 1.46 cm), TSW (160.67 ± 4.85 g), biomass (14941 ± 200.92 kilograms/ha), and grain output (7544 ± 119.49 kilograms/ha) have been attained by combining 150 kilograms/ha NPSB and 90 kilograms/ha K fertilizer rate. Following this, maximum quantity of seeds per row (44.88 ± 1.67) and seeds per ear (705.87 ± 25.61) have been attained from combination of 150 kilograms/ha NPSB and 60 kilograms/ha K fertilizer rates. Economic analysis revealed that maximum net profit (1491 Dollar/ha) and marginal rate of return (MRR) 1196.67% have been achieved from combining 150 kilograms/ha NPSB and 60 kilograms/ha K fertilizer rates. This investigation revealed that the combination of the NPSB fertilizer level of 150 kilograms/ha and 60 kilograms/ha K fertilizer showed superior performance with higher grain yield and economic return over other treatments. Therefore, a combined application of 150 kilograms/ha NPSB with 60 kilograms/ha K fertilizer rates could be recommended for maize production in the study area and similar agro-ecologies
Characterization and Evaluation of Bambara Groundnut (Vigna subterranea (L.) Verdc.) for Yield and Related Traits in Asosa Zone, Northwestern Ethiopia
No full textBambara groundnut, a future emerging legume, is usually known as a poor man’s crop or as “women’s crop” and newly noted as crop for new millennium. In this context, a field experiment was conducted during 2019/20 cropping season at Sonka testing site of Asosa zone in northwestern Ethiopia with objective to estimate the variability of Bambara groundnut genotypes with respect to important quantitative and qualitative traits. Treatments consisted in 20 accessions collected from five distracts of Benishangul Gumuz province in northwestern Ethiopia. The treatments were laid out in a randomized block design with three replications. All the qualitative characteristics recorded for genotypes showed different modalities and frequencies at vegetative stage with 70.12% of the fully expanded leaflet colour, 74.26% oval terminal leaflet shape, 76.24% petiole green colour, 78.22% stem green colour, 88.27% sparse hair on their stems, 70.41% spreading types, 81.33% rounded base with a point at the top, 90.11% yellowish brown pods at harvest, and 90.06% oval shaped seeds. With respect to quantitative traits, genotypes AMN/04/013, AMN/04/014, AMN/04/015, AMN/04/019, and AMN/04/020 gave relatively higher grain yield (>2000 kg/ha) with the highest grain yield recorded for genotype AMN/04/016. Thus, these genotypes showed relatively better adaptation at tested location. Higher correlation values were observed for days to maturity, plant height, number of stems per plant, pods per plant, seed per pod, and HSW, indicating that these traits are very important to be used in selection for the crop improvement. Agronomic and morphological evaluations have provided more accurate estimation of genetic diversity, the raw material of plant breeding. In general, this study enabled to determine how the influential traits direct to improve Bambara groundnut genotypes
Evaluation of food barley (Hordeum vulgare L.) varieties on yield and yield components at different rates of blended nitrogen, phosphorus, sulfur and boron fertilizer rates at Kechi, Southern Ethiopia
Get PDFBarley is an important cereal crop in Ethiopia, accounting for nearly 25% of the total production. However, the trend of food barley production in the area has been declining for the past few years. The major production constraints for food barley production in Ethiopia, including the study area, are soil acidity and soil fertility. As a result, a field experiment was carried out during the 2019/20 cropping season at Wolaita Sodo University's Kechi testing site with the objective of evaluating the response of food barley varieties to NPSB fertiliser rates. Three food barley varieties (HB 1307, EH 1493, and local cultivar) and five NPSB fertiliser rates (0, 50, 100, 150, and 200 kg/ha) were used in the treatments. The treatments were combined in a factorial design and laid out in a randomised complete block design (RCBD) with three replications. Data for yield and yield related parameters were recorded during the specific phenological stage of the crop. The results revealed that days to heading and maturity were prolonged for all varieties as NPSB rates increased, with the longest days to heading and maturity recorded for variety BH 1307 at a NPSB rate of 200 kg/ha. At a NPSB fertiliser rate of 200 kg/ha, variety EH 1493 had the tallest plant heights and the longest spike length. The highest number of seeds per spike was observed for variety EH1493 at an NPSB rate of 150 kg/ha, whereas the highest TSW was seen for variety EH1493 at an NPSB rate of 100 kg/ha. The greatest biomass yield was obtained from variety BH 1307 at an NPSB fertiliser rate of 200 kg/ha, and the highest grain yield was observed for variety EH 1493 at an NPSB rate of 100 kg/ha. This result revealed that varieties EH 1493 and BH 1309 showed superior performance with better grain over local cultivars at NPSB fertiliser rates of 100 kg/ha. Based on the results of this study, it could be concluded that this blended NPSB application rate is superior for the production of food barley in the study area.  
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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