Developing a Geographic Information System (GIS) application for soils and crop suitability studies in Atwima District of Ghana

This paper reports a study that sought to develop a Geographic Information System (GIS) application for soils and their crops suitability in the Atwima District. The purpose of the study was to digitally capture, store, and analyze the soil map and crops suitability data of the district. GIS is a computer-based system for gathering, storing, manipulating and analyzing spatial data to support decision making. In this study, the soil map of the Atwima district was digitized and analyzed with GIS software called ArcView. The soil characteristics and crops suitability data were also added in tabular form to the database. A thematic map showing soil associations and their crop suitability was then generated from the database and displayed concurrently with the tabular data. Analysis of the map and table proved that it is easier to study soils and their suitable crops from their data displayed concurrently on the desktop. It was therefore concluded that developing GIS application for the study of soils and crops suitability is an effective way of bringing all related datasets together to support agricultural research and decision making. The main recommendation was that agricultural students must develop a comprehensive GIS database that will include all datasets relevant to soils and crops studies and management.Keywords: geographic information system, digitalized soil map, soils and crops studie

Bioactivity of some natural products against the cowpea storage weevil Callosobruchus Maculatus L.

This work was carried out to evaluate the insecticidal activity of extracts from 14 plant species of Ghanaian origin against Callosobruchus maculatus adults under laboratory conditions. Phytochemical screenings of the 14 plant species were performed using standard laboratory methods to determine the types of secondary natural products present in the plant species. Aqueous, petroleum ether and ethanolic extracts of the 14 plant species were screened for their bioactivity against Artemia selina in a brine shrimp lethality test. The pesticidal activities of the plant products against Callosobruchus maculatus were investigated in laboratory experiments. Contact toxicity (filter paper impregnation method), grain treatment with plant products for insect population and mortality assays, and also effect of the plant products on grain damage were obtained and compared with Actellic Super EC (synthetic insecticide) during a three-month observation period. Cymbopogan winterianus oil caused the highest mortality, least damage to grains and the highest antireproductive effect. All grain-protective properties of the natural products were concentration and time dependent. Extracts of Cassia alata showed good potential in protecting cowpea and gave better protection than the powder, whilst Griffornia simplicifolia did not significantly protect the grains. Phytochemical investigations of the plants revealed the presence of terpenes, saponins, tannins, glycosides, alkaloids, anthraquinones and flavonoids. The presence of some of these compounds may be responsible for the pesticidal action of the plants.Keywords: Phytochemical screening, Extracts, Insecticidal, Brine shrimp lethality test, Cowpea

Edible Coating

Postharvest losses are rampant due to lack of proper storage conditions and handling of the fresh food products. The perishable nature of fruits and vegetables makes their shelf life limited due to some extrinsic factors such as some environmental conditions and preservation conditions as well as some intrinsic factors such as respiration rate, ethylene production and transpiration. Among the other postharvest technologies available, edible coatings seems to be one novel method which has been verified to have a positive and safe approach to extending the shelf life of products. This type of packaging is made from various natural resources like polysaccharide, protein and lipid materials. Edible packaging materials can be divided into two main groups including edible coatings and edible films. It has so many benefits such as serving as a moisture barrier, oxygen scavenger, ethylene scavenger, antimicrobial properties among others. Different methods of application of the edible coating on the food materials include; dipping, spraying, brushing, layer by layer among others. There have been several verifications of the positive impact of edible coatings/films on pome fruits, Citrus fruits, Stone fruits, tropical and exotic fruits, berries, melon, tomatoes and others

Levels of infestation on three different portions of the maize cob by the weevil Sitophilus zeamais (motschulsky)

The maize weevil, Sitophilus zeamais is a major storage pest of maize that causes significant quantitative and qualitative losses to the farmer. The extent of damage caused by S. zeamais to stored maize depends on the initial level of infestation on the field before harvest. The levels ofinfestations on three different portions of maize cob were studied. Maize was planted during the minor planting season (September-December) of 2008. Maize seeds were sown on 9 plots each measuring 7.0 m x 1.5 m. Matured maize cobs were harvested 110 days after emergence. Tencobs were randomly selected from each of the plots, dehusked and cut into three portions: top, middle and bottom and stored separately in sealed plastic containers for 5 weeks. Weevils were counted weekly during the storage period. Percent damaged seeds and numbers of holes on damaged grains were counted for each portion. Percent weight loss due to S. zeamais infestation was calculated for the different maize portions. Weevil infestations were recorded on all the portions 1 week after storage. Large numbers of S. zeamais were recorded on all the portions at the endof the storage period. The middle portion recorded significantly more S. zeamais than the top and bottom portions. Percent damaged seeds; percent weight loss and mean number of holes on damaged seeds did not differ significantly

Bio-ecological studies of the mango stone weevil in southern Ghana

Field and laboratory studies were conducted to determine the distribution and biology of the mango stone weevil, Sternochetus mangiferae, in southern Ghana. The weevil was found in the coastal savanna and rain forest areas but appeared to be absent from the forest/savanna transition zones. All mango varieties were attacked within the infested zones, with higher rates of infestation in the more humid areas. Elsewhere, the weevil is reported to contribute substantially to premature fruit drop and causes reduction in yield. The eggs appear to be laid in young fruits over a period of time as some fruits recorded multiple infestations with all stages of development observable in a single fruit. In the laboratory both larvae and adults were reared on excised mango cotyledons, but it is doubtful that adults survive on cotyledons in the field. Larvae pupated for 6-7 days with a pre-pupal stage of 1-2 days. Adults are long lived and have been cultured in the laboratory for up to 6 months. Adults were found hibernating in cracks and crevices on trunks of old mango trees (> 20 years after planting). Similar hiding places could not be found on young trees (³ 10 years after planting). It is, thus, possible that trees other than mangoes provide hibernation sites for the weevil between fruiting seasons. Adult weevils readily accepted and climbed onto flowers but did not show any preference for bark, twigs, leaves or soil. The acceptance of the flowers by the adults seems to suggest that flowers may provide food and breeding sites. Infestation by the weevil did not affect fruit quality despite the high potential to disrupt the export trade in mangoes. The low quarantine rejection threshold of one fruit in 40 set in the export market suggests that solution to the problem posed by the weevil requires socioeconomic, political and scientific initiatives

Design and manufacturing of a benchtop thermoforming machine

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Page 39 blank. Cataloged from PDF version of thesis.Includes bibliographical references (page 38).The following work details the design and fabrication of a tabletop thermoform machine with the goal of making this machine cheaper than the ones on the market, yet able to fulfill specific requirements. These functional requirements include creating parts that have dimensions within .05" of the original part; thermoforming plastics that range between a 3" x 3" and 12" x 12" size; and having the ability to heat the plastic to at least 150°C in order to thermoform plastics such as polycarbonate. In addition, this machine had to be simple to manufacture and use. In order to achieve these requirements, a top to bottom drape forming architecture with a four bar linear slider and carriage, was constructed. In order to constrain the plastics of different sizes, two similar, modular wooden plates were used such that the plastic was held in between them via t-nuts and screws. When the user clamps the plastic onto the carriage, he or she slides the carriage upwards to an oven that radiates heat via nichrome wire on a mica sheet. Once the desired temperature is reached, the user then slides the carriage down onto a vacuum box platform, where a mold is present, and forms the plastic over the mold. While that happens, a negative pressure is applied inside the box via a standard commercial vacuum, so that the plastic adheres more closely to the mold. For the testing process, this work focuses on two manufacturing strategies for thermoforming parts: heating the air to the glass transition temperature before thermoforming, and heating the plastic to the glass transition temperature before thermoforming. Once this test was performed, the dimension of each plastic part was examined in order to see if the tolerance levels were reached. In addition, this test determined whether or not there was a statistical significance between the qualities of parts made by either of these processes. In the end, the thermoform machine was only able to reach an average tolerance of .07" for the created parts. In addition, there was no statistical significance between the part qualities of either one of the tested manufacturing processes. Some of the main reasons behind this include having an ineffective vacuum box and clamp design issues, which will be focused on in the future iteration of this project.by Akwasi Owusu-Akyaw.S.B

A Comparative Nutritional Analysis of Przewalski’s Horses and Asiatic Wild Asses

In 1992, the, then critically endangered, Przewalski’s horse (Equus przewalskii) was re-introduced into the Great Gobi B Protected Area in southwestern Mongolia, in an effort to re-establish the species within its historic range. This semi-desert region also sustains relatively large populations of the closely-related, threatened Asiatic wild ass (Equus hemionus). Though the extensive ranges of both species once overlapped, it is unclear whether or not the same overlap in a much smaller area will cause competition between the two for food. The goal of this study was to compare the equids’ nutritional niches and see if they overlapped. Captive individuals from each species were given four different mixtures of hay, with the amount consumed daily recorded. The species-specific dietary decisions were then visualized and characterized using the Geometric Framework proposed by Stephen Simpson and David Raubenheimer. The results suggest that the Przewalski’s horse consumes more water and energy per kilogram body weight than the Asiatic wild ass, and that the wild ass tended to shift towards the more protein-rich food options than the Przewalski’s horse. The study ultimately concludes that the two species occupy two distinct nutritional niches, and, unnatural pressures withstanding, are likely capable of co-existing in the Great Gobi B

Insect Pests Of Dried Cassava (‘Kokonte\') in Ashanti and Brong Ahafo Regions of Ghana

Insects are among the most important agents of postharvest losses of dried stored produce including cassava. In a study to identify the most important insects and assess the damage, dried cassava samples from marketing centers in 8 districts each in Ashanti (Mampong, Nkawie, Konongo, Tepa, Nkenkasu, Kumasi, Ejura and Bekwai), and Brong Ahafo (Berekum, Dormaa Ahenkro, Techiman, Sene, Acherensua, Sunyani, Kintampo and Bechem) were incubated in the laboratory. For each sample, a questionnaire was administered to collect information on the cassava varieties processed, method of preparation, drying and storage. Ninety-nine percent of ‘kokonte' samples collected from the Brong Ahafo region were sun dried compared with 59% from Ashanti. Samples from Ashanti had been predominantly stored in open baskets (46%) while in the Brong Ahafo the principal method had been in empty fertilizer sacks (42%). Much of the kokonte ready for the market in both regions were stored for a maximum period of one week. The red skin variety of cassava is preferred to the white skin accounting for 67% and 85% of kokonte from Ashanti and Brong Ahafo, respectively. Eleven insect species, all beetles from six families were identified from the two regions. The coffee bean weevil, Araecerus fasciculatus (Degeer) (Coleoptera: Bostrichidae), was the most predominant species. Other important species were Sitophilus zeamais (Motsch.) (Coleoptera: Curculionidae), Cryptolestes sp. (Coleoptera: Cucujidae), Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), Dinoderus minutus (Fabricius) and Cathartus quadricollis Guerin (Coleoptera: Silvanidae). They were important because of their numbers and the potential to cause damage. Of significance was the occurrence in small numbers in both regions of the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), in samples. The potential of this insect to cause damage and implications for post harvest storage of dried produce are discussed. Journal of the Ghana Science Association Vol. 9 (2) 2007: pp. 9-1