OAR@UM Collection:

The effects of zinc on soil microbial activity

2018-12-07T08:01:34Z

Title: The effects of zinc on soil microbial activity Abstract: Microbial activity in soil is an important factor. It keeps a soil healthy as it plays an important aspect in nutrient cycling. Microbial activity is sensitive to a number of factors such as pollutants. Heavy metals such as Zn could be a common soil contaminant. Zn based fungicides are used extensively in Malta and these together with the practice of farm yard manure application to soil could lead to high levels of Zn. The effect of Zn on soil microbial activity was investigated. A Luvisol from Malta was amended with increasing concentrations (100, 150 and 300 ppm) of Zn and incubated under controlled conditions for 8 weeks. Microbial activity was tested at two weeks’ interval by performing an arginase, urease and protease enzyme assays and a respiration rate test. The findings of this study did not show a clear effect of Zn on soil microbial activity. This could be due to a number of factors which could include, a low level of contamination, availability of cation caused by the high soil pH, and also fluctuations in soil water content. Soil microbial activity was low due to the fact that soils of Malta are very low in organic matter content. Furthermore, soil pH influences Zn and its availability, the highest concentration of Zn used (300 ppm) was reduced to 205 ppm Zn as the available form. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT.

The morphometric and polyphenolic analysis of indigenous and international grape varieties grown in the Maltese islands

2018-12-07T07:59:26Z

Title: The morphometric and polyphenolic analysis of indigenous and international grape varieties grown in the Maltese islands Abstract: Five indigenous Maltese grape vine varieties (Abjad Tond , Beżżul Abjad , Miġnuna, Ġellewża and Girgentina) and five international grape varieties (Carignan, Tempranillo, Catarratto, Greco di Tufo and Grillo) were selected to study their morphometric and physicochemical properties. The results served to compare the native grapes with the international grapes. The ten grape varieties had %brix of 13.3 to 22.5%. Intrestingly, the Miġnuna variety had the highest brix value compared to those of the international varieties (<22.5%). pH ranged between 3.46 and 4.59, where the Girgentina variety had the lowest pH (3.78) and the Beżżul Abjad had the highest pH (4.51). Adding to that, the UV-Vis analysis revealed that Tempranillo had the highest colour intensity (7.5340), whist the lowest was for Abjad Tond (0.3772). Carignan showed the lowest tonality (0.2217) and the Girgentina with the highest tonality ratio (2.9592). The highest anthocyanin content was in Tempranillo (124.00 mg/kg) while the lowest was in Girgentina (1.0 mg/kg). The polyphenolic content demonstrated that the international varieties exhibited greater polyphenolic concentrations than the the Maltese varieties (p<0.0001). Values ranged between 0.0085 and 0.101 % w/w. Furthermore, metal analysis showed that silver levels were significantly different between the ten varieties (p<0.0001). Chromium concentrations were observed to be 0.1096 - 0.2899 mg/kg for the ten grape types. The copper concentration varied between 0.6665 and 1.686 mg/kg. The iron concentration ranged between 0.8549 and 2.956 mg/kg. The Maltese varieties had iron content ranging between 0.8549 and 1.53 mg/kg. Potassium levels ranged between 211.8 and 749.2 mg/kg. The magnesium levels ranged between 36.92 and 202.9 mg/kg. The Maltese varieties exhibited the lowest magnesium content (36.92-49.98 mg/kg), as compared to the international varieties. Morphometric analysis revealed that grape width for the ten varieties varied between 8.662 and 19.22 mm. The five Maltese varieties exhibited the largest widths between 17.49 and 19.22 mm. Grape length for the ten varieties varied between 9.135 and 20.10 mm, where the Beżżul Abjad grape had largest length compared to the 10 varieties (23.49 mm). In conclusion, statisical analysis illustrated that the physicochemical characteristics and mineral content differ between the red and white varieties. Adding to that morphometric characteristics observed indicate that there significant differences between the indigenous and international varieties. This was revealed by Agglomerative Hierarchical Clustering analysis for the metal parameters. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT.

Identifying constrains that are hindering the Maltese pork industry

2018-12-07T08:39:21Z

Title: Identifying constrains that are hindering the Maltese pork industry Abstract: Pig production in Malta has been considered to be a profitable industry but this changed upon Malta accession with the European Union. Data compiled by the National Statistics Office shows that; after accession demand for local pork constantly decreased as importation of pork started to replace local pork. The pig breeders cooperative (K.I.M Ltd) invested in cutting and deboning facility to keep the market share but there is still low demands for pork especially ham and shoulder. Following this decrease in demand this study was made to generating information on the pork industry through specifically targeted interviews and on consumer behaviour and preference with regards to the consumption of pork through a questionnaire. By a series of interviews within the pork industry and consumer surveys done in five localities, factors that affect the local pork demand were identified together with the improvements needed to be done by the pork chain to increase the local pork demand. By analysing the pork market and the consumer demand; K.I.M Ltd can direct pig producers so the products satisfy the demand of the consumers and the other sectors in the industry. This will result in an increase in local pork demand and the pig industry will be more profitable and more sustainable. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT.

The effects of water stress on the growth and physicochemical parameters in pot herbs

2018-12-07T08:38:24Z

Title: The effects of water stress on the growth and physicochemical parameters in pot herbs Abstract: This work investigates the effects of water stress on the growth and physicochemical characteristics of three types of potted herbs, namely basil (Ocimum basilicum), mint (Mentha spicata), and sage (Salvia officinalis). The herbs were grown in compost premium peat moss. Seedling were treated with four different water regimens at 100%, 50%, 25% and 12.5% compost water capacity over a period of 72 days during August and September 2017. From the plant growth characteristics, it was observed that the order of herbs tolerant to water stress was basil, followed by mint and lastly sage. Mint was affected by water stress but managed to regenerate and recover from injury for those plants that experienced wilting and death. On the other hand, sage was the least tolerant, and several losses were observed. Physicochemical analysis revealed that the status of phytochemicals in the mint was superior to that of sage and lastly basil and that water stress affected the phytochemical status for all three species to various extents. This showed that although basil was tolerant to water stress, it did not yield the optimum metabolite yield. Qualitative analysis of the essential oil revealed that the major constituent of basil was eugenol, for mint, these were menthol and pulegone, while for sage oil, these were thujone and cineole. With regards to minerals, a conclusion cannot be drawn from these results, meaning that mineral content could not be used to distinguish between the three species or how water stress affected minerals in leaves. This study revealed the possible use of these three plants as pot herbs in an urban setup. This may extend the aesthetic and culinary use of herbs in urban setups to be alternatively developed into medicines, food supplements and cosmetics. Description: B.SC.(HONS)MED.AGRO-ECO.MANGT.