Nutrient Content Research Papers - Academia.edu (original) (raw)
Status of organic carbon (C), total nitrogen (N), available potassium (K), calcium (Ca) and phosphorus (P) in three different depths (0−5 cm, 5−15 cm and 15−30 cm) on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro... more
Status of organic carbon (C), total nitrogen (N), available potassium (K), calcium (Ca) and phosphorus (P) in three different depths (0−5 cm, 5−15 cm and 15−30 cm) on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those in degraded bush forests, through digging three profiles in each land use. The content of all the five nutrients was found to be higher in the soil of orange orchard than in the soil of forest. But the variation was not consistent for both the slopes. The content varied depth wise also, having the highest value in surface soil in case of both the land uses on both the slopes. A mean available K content was significantly higher in orange orchard than in forest on 55% slope, while it was lower on 35% slope. Surface soil contained the nutrients of K and Ca with the amount of 0.2905-mg·g -1 soil and 3.025-mg·g -1 soil respectively in the orchard, while 0.1934-mg·g -1 soil and ...
... C. Mark Moore 1, 2 , Matthew M. Mills 3 , Eric P. Achterberg 2 , Richard J. Geider 1 , Julie LaRoche 4 , Mike I. Lucas 5 , Elaine L. McDonagh 2 , Xi Pan 2 , Alex J. Poulton 2 , Micha JA Rijkenberg 2 ... Figure 1: Cruise tracks and... more
... C. Mark Moore 1, 2 , Matthew M. Mills 3 , Eric P. Achterberg 2 , Richard J. Geider 1 , Julie LaRoche 4 , Mike I. Lucas 5 , Elaine L. McDonagh 2 , Xi Pan 2 , Alex J. Poulton 2 , Micha JA Rijkenberg 2 ... Figure 1: Cruise tracks and maps of annual mean excess nutrient distributions. ...
- by Sara Duvenage and +1
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- Economics, Brand Loyalty, Applied Economics, Urbanisation
This paper assesses consumers’ acceptance of nutritionally enhanced vegetables using a series of auction experiments administered to a random sample of adult consumers. Evidence suggests that consumers are willing to pay significantly... more
This paper assesses consumers’ acceptance of nutritionally enhanced vegetables using a series of auction experiments administered to a random sample of adult consumers. Evidence suggests that consumers are willing to pay significantly more for fresh produce with labels signaling enhanced levels of antioxidants and vitamin C achieved by moving genes from within the species, as opposed to across species. However,
Effects of lime and gypsum applications on the quality of soybeans grown under no-till (NT) are not well defined yet. A field trial established in 1998 on a dystrophic clayey Rhodic Hapludox, at Ponta Grossa, State of Paraná, Brazil,... more
Effects of lime and gypsum applications on the quality of soybeans grown under no-till (NT) are not well defined yet. A field trial established in 1998 on a dystrophic clayey Rhodic Hapludox, at Ponta Grossa, State of Paraná, Brazil, evaluated grain yield and soybean quality based on oil, protein and nutrient content, after lime and gypsum applications under NT, in a randomized complete block design (n = 3), split-plot experiment. In the main plots, the treatments with dolomitic lime were: control (no lime), split application of lime on the surface (three yearly applications of 1.5 Mg ha¹), surface lime (4.5 Mg ha¹), and incorporated lime (4.5 Mg ha¹). Subplots received four different rates of gypsum: 0, 3, 6, and 9 Mg ha-1. The soybean crop was evaluated in the agricultural years of 20022003 and 20032004. After 58 months, the correction of acidity through surface liming, with full or split rates, was more pronounced in the top layer (00.05 m) and there was greater reaction at the d...
Detailed ethnographic records of hunter- gatherer subsistence diet among the Ngaatjatjarra Aboriginal people made by the ethnoarchaeologist, Richard Gould, in the Western Desert in 1969 have been analysed for nutrient composition using a... more
Detailed ethnographic records of hunter- gatherer subsistence diet among the Ngaatjatjarra Aboriginal people made by the ethnoarchaeologist, Richard Gould, in the Western Desert in 1969 have been analysed for nutrient composition using a 1993 table of Indigenous foods. Over a period of five months the dietary staples of meat, fresh and dried fruit and grass seeds provided group members with
Today vegetarian nutrition is more accepted and widespread in Europe than in former years. For a long time scientific research on vegetarian diets has focused mostly on malnutrition, whereas nowadays research centers increasingly on the... more
Today vegetarian nutrition is more accepted and widespread in Europe than in former years. For a long time scientific research on vegetarian diets has focused mostly on malnutrition, whereas nowadays research centers increasingly on the preventive potential of plant-based diets. We followed a nutritive and a metabolic-epidemiological approach to obtain dietary recommendations. A MEDLINE research was performed for all plant food groups relevant for a vegetarian diet (key words: all relevant food groups, "vegetarian diet", "chronic disease", "cancer", "cardiovascular disease", "diabetes mellitus", "osteoporosis"). All relevant food groups were characterized regarding their nutrient content and rated with respect to the available metabolic-epidemiological evidence. Based on the evidence criteria of the WHO/FAO, cancer risk reduction by a high intake of vegetables and fruits is assessed as probable or possible, while a lowered risk of cardiovascular disease is convincing and a lowered risk of osteoporosis is probable. The evidence of a risk reducing effect of whole grain relating to colorectal cancer is assessed as possible, whereas it is probable relating to cardiovascular disease and diabetes mellitus type 2. There is an insufficient risk-reducing effect of legumes like soja relating to epithelial tumours and cardiovascular disease. The evidence of a risk-reducing effect of nuts to cardiovascular disease is assessed as probable, and in relation to cholelithiasis and diabetes mellitus type 2 as possible and insufficient, respectively. In conclusion, high consumption of fruits, vegetables, whole grains and nuts can lower the risk for several chronic diseases. In Europa findet der Vegetarismus zunehmend Verbreitung und Akzeptanz. Während früher mögliche Mangelerscheinungen bei vegetarischer Ernährung im Fokus der Ernährungswissenschaft standen, rückt heute zunehmend das präventive Potential einer pflanzenbetonten Ernährung in den Vordergrund des Interesses. Für die Entwicklung entsprechender Ernährungsempfehlungen fanden ein nutritiver und ein metabolischepidemiologischer Ansatz Verwendung. Dazu wurde eine MEDLINE-Recherche für die im Rahmen einer vegetarischen Kostform relevanten pflanzlichen Lebensmittelgruppen durchgeführt (Schlüssel-Suchbegriffe: alle relevanten Lebensmittelgruppen, "vegetarian diet", "chronic disease", "cancer", "cardiovascular disease", "diabetes mellitus", "osteoporosis"). Die einzelnen Lebensmittelgruppen wurden hinsichtlich ihrer ernährungsphysiologischen Eignung und anhand der verfügbaren metabolisch-epidemiologischen Evidenz bewertet. Auf Basis der Evidenzkriterien der WHO/FAO zeigt sich, dass ein risikosenkender Effekt eines hohen Obst- und Gemüseverzehrs bei epithelialen Tumoren als wahrscheinlich oder möglich, bei kardiovaskulären Erkrankungen als überzeugend, bei Diabetes mellitus Typ 2 als unzureichend sowie bei Osteoporose als möglich gilt. Die Evidenz für einen risikosenkenden Effekt des Vollkornverzehrs im Hinblick auf Tumoren des Kolons und Rektums gilt als möglich, bei kardiovaskulären Erkrankungen und Diabetes mellitus Typ 2 als wahrscheinlich. Bei Hülsenfrüchten wie Soja wird die Evidenz für einen risikosenkenden Effekt sowohl in Bezug zum Risiko epithelialer Tumoren als auch bei kardiovaskulären Erkrankungen als unzureichend bewertet. Die Evidenz für einen risikosenkenden Effekt des Nussverzehrs gilt bei kardiovaskulären Erkrankungen als wahrscheinlich, bei Diabetes mellitus Typ 2 als unzureichend und bei Cholelithiasis als möglich. Daraus lässt sich schließen, dass der reichliche Konsum von Obst, Gemüse, Vollkornprodukten und Nüssen das Risiko für verschiedene chronisch-degenerative Erkrankungen vermindert.
Objective The aim of the study was to test the feasibility of using smart card technology to track the eating behaviours of nearly a thousand children in a school cafeteria.Methods Within a large boys’ school a smart card based system... more
Objective The aim of the study was to test the feasibility of using smart card technology to track the eating behaviours of nearly a thousand children in a school cafeteria.Methods Within a large boys’ school a smart card based system was developed that was capable of providing a full electronic audit of all the individual transactions that occurred within the cafeteria. This dataset was interfaced to an electronic version of the McCance and Widdowson composition of foods dataset. The accuracy of the smart card generated data and the influence of portion size and wastage were determined empirically during two 5-day trials.Results The smart card system created succeeded in generating precise data on the food choices made by hundreds of children over an indefinite time period. The data was expanded to include a full nutrient analysis of all the foods chosen. The accuracy of this information was only constrained by the limitations facing all food composition research, e.g. variations in recipes, portion sizes, cooking practices, etc. Although technically possible to introduce wastage correction factors into the software, thereby providing information upon foods consumed, this was not seen as universally practical.Conclusion The study demonstrated the power of smart card technology for monitoring food/nutrient choice over limitless time in environments such as school cafeterias. The strengths, limitations and applications of such technology are discussed.
Today vegetarian nutrition is more accepted and widespread in Europe than in former years. For a long time scientific research on vegetarian diets has focused mostly on malnutrition, whereas nowadays research centers increasingly on the... more
Today vegetarian nutrition is more accepted and widespread in Europe than in former years. For a long time scientific research on vegetarian diets has focused mostly on malnutrition, whereas nowadays research centers increasingly on the preventive potential of plant-based diets. We followed a nutritive and a metabolic-epidemiological approach to obtain dietary recommendations. A MEDLINE research was performed for all plant food groups relevant for a vegetarian diet (key words: all relevant food groups, "vegetarian diet", "chronic disease", "cancer", "cardiovascular disease", "diabetes mellitus", "osteoporosis"). All relevant food groups were characterized regarding their nutrient content and rated with respect to the available metabolic-epidemiological evidence. Based on the evidence criteria of the WHO/FAO, cancer risk reduction by a high intake of vegetables and fruits is assessed as probable or possible, while a lowered risk of cardiovascular disease is convincing and a lowered risk of osteoporosis is probable. The evidence of a risk reducing effect of whole grain relating to colorectal cancer is assessed as possible, whereas it is probable relating to cardiovascular disease and diabetes mellitus type 2. There is an insufficient risk-reducing effect of legumes like soja relating to epithelial tumours and cardiovascular disease. The evidence of a risk-reducing effect of nuts to cardiovascular disease is assessed as probable, and in relation to cholelithiasis and diabetes mellitus type 2 as possible and insufficient, respectively. In conclusion, high consumption of fruits, vegetables, whole grains and nuts can lower the risk for several chronic diseases. In Europa findet der Vegetarismus zunehmend Verbreitung und Akzeptanz. Während früher mögliche Mangelerscheinungen bei vegetarischer Ernährung im Fokus der Ernährungswissenschaft standen, rückt heute zunehmend das präventive Potential einer pflanzenbetonten Ernährung in den Vordergrund des Interesses. Für die Entwicklung entsprechender Ernährungsempfehlungen fanden ein nutritiver und ein metabolischepidemiologischer Ansatz Verwendung. Dazu wurde eine MEDLINE-Recherche für die im Rahmen einer vegetarischen Kostform relevanten pflanzlichen Lebensmittelgruppen durchgeführt (Schlüssel-Suchbegriffe: alle relevanten Lebensmittelgruppen, "vegetarian diet", "chronic disease", "cancer", "cardiovascular disease", "diabetes mellitus", "osteoporosis"). Die einzelnen Lebensmittelgruppen wurden hinsichtlich ihrer ernährungsphysiologischen Eignung und anhand der verfügbaren metabolisch-epidemiologischen Evidenz bewertet. Auf Basis der Evidenzkriterien der WHO/FAO zeigt sich, dass ein risikosenkender Effekt eines hohen Obst- und Gemüseverzehrs bei epithelialen Tumoren als wahrscheinlich oder möglich, bei kardiovaskulären Erkrankungen als überzeugend, bei Diabetes mellitus Typ 2 als unzureichend sowie bei Osteoporose als möglich gilt. Die Evidenz für einen risikosenkenden Effekt des Vollkornverzehrs im Hinblick auf Tumoren des Kolons und Rektums gilt als möglich, bei kardiovaskulären Erkrankungen und Diabetes mellitus Typ 2 als wahrscheinlich. Bei Hülsenfrüchten wie Soja wird die Evidenz für einen risikosenkenden Effekt sowohl in Bezug zum Risiko epithelialer Tumoren als auch bei kardiovaskulären Erkrankungen als unzureichend bewertet. Die Evidenz für einen risikosenkenden Effekt des Nussverzehrs gilt bei kardiovaskulären Erkrankungen als wahrscheinlich, bei Diabetes mellitus Typ 2 als unzureichend und bei Cholelithiasis als möglich. Daraus lässt sich schließen, dass der reichliche Konsum von Obst, Gemüse, Vollkornprodukten und Nüssen das Risiko für verschiedene chronisch-degenerative Erkrankungen vermindert.
An experiment was conducted at the experimental field of Sher-e-Bangla Agricultural University, Bangladesh during the period from February to April of 2012 to find out the effect of different levels of nitrogen on growth and yield... more
An experiment was conducted at the experimental field of Sher-e-Bangla Agricultural University, Bangladesh during the period from February to April of 2012 to find out the effect of different levels of nitrogen on growth and yield performance as well as nutrient content of mungbean (BARI Mung 6). Four levels of nitrogen, viz., N0 (Control), N1 (10 kgha-1), N2 (20 kgha-1) and N3 (25 kgha-1) were used on experiment followed by Randomized Complete Block Design with three replications. Maximum plant height (40.52 cm), number of leaves (19.14), number of branches (10.09), average dry weight/plant (7.35 g), number of pods/plant (15.90), number of seeds/pod (4.49), 1000-seed weight (42.56 g), seed yield (1.06/ha), stover yield (2.08/ha), N content in seed (3.60), P content in seed (0.48) and K content in seed (1.26) were found in N3 which was statistically similar with N2 whereas minimum from N0.
- by H. Mehraj
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- Growth, Yield, Nutrient Content, Mungbean
Compost is a simple way of creating what scientists call a positive feedback loop. This study was conducted to determine the pH, N, P, and moisture content; the number of days to decomposition; the percent recovery of composted... more
Compost is a simple way of creating what scientists call a positive feedback loop. This study was conducted to determine the pH, N, P, and moisture content; the number of days to decomposition; the percent recovery of composted substrates; and the return on cash expense of producing the formulated sunflower-based compost. The substrates used in the study were wild sunflower, grass, alnus leaves and banana bract. These were composted until it becomes recognizable. The grass, alnus leaves, and banana bract are constant in weight which is 10 kg each, only the sunflower varied in rate. Different rates of wild sunflower in the treatments were the following: T1=10 kg, T2=20 kg, T3=30 kg, T4=40 kg and T5=50 kg. Results showed that chemical and moisture contents of formulated wild sunflower-based compost were not affected by the different rates of wild sunflower except N. Treatment 4 (4:1:1:1 of wild sunflower, grass, alnus leaves and banana bract) obtained the highest N content with 3.21 %. The lowest was registered from the formulation of 1:1:1:1 of wild sunflower, grass, alnus leaves and banana bract (T1) with 2.21 %. The higher the rate of wild sunflower, the early and the higher are the number of days to decompose and the percentage of its recovery, respectively. Treatment 5 (5:1:1:1 of wild sunflower, grass, alnus leaves and banana bract) gained a higher return on cash expense with 13.05 %.
- by IJMRE Journal and +1
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- Organic Chemistry, Decomposition, Nutrient Content, Compost
In 2009 a greenhouse experiment was conducted to determine the effects of boron (B) and plant growth-promoting rhizobacteria (PGPR) treatments, applied either alone or in combination, on yield, plant growth, leaf total chlorophyll... more
In 2009 a greenhouse experiment was conducted to determine the effects of boron (B) and plant growth-promoting rhizobacteria (PGPR) treatments, applied either alone or in combination, on yield, plant growth, leaf total chlorophyll content, stomatal conductance, membrane leakage, and leaf relative water content of wheat (Triticum aestivum L. cv. Bezostiya) and barley (Hordeum vulgare L. cv. Tokak) plants. Results showed that alone or combined B (0, 1, 3, 6, 9 kg ha−1) and PGPR (Bacillus megaterium M3, Bacillus subtilis OSU142, Azospirillum brasilense Sp245, and Raoultella terrigena) treatments positively affected dry weight and physiological parameters searched in both species. Statistically significant differences were observed between bacterial inoculation and B fertilizer on root and shoot dry weight under non-cold-stress (NCS) and cold-stress (CS) conditions. Leaf total chlorophyll content (LTCC), stomatal conductance (SC), leaf relative water content (LRWC), and membrane leakage (ML) were negatively affected by CS conditions and decreased with reduced temperatures of media, but B and PGPR application alleviate the low-temperature deleterious effect in both species. The greatest SC and LRWC, and the lowest ML, were obtained by 6 kg B ha−1 combined with R. terrigena treatment. The greatest LTCC in both NCS and CS conditions was observed with B. megaterium M3 application alone.
Food is a most essential surviving tool fulfilling the basic requirement of hunger and also preserves essential nutrients for good health. Finger millet (ragi) (Eleusine coracana) grains were given various processing treatments like... more
Food is a most essential surviving tool fulfilling the basic requirement of hunger and also preserves essential nutrients for good health. Finger millet (ragi) (Eleusine coracana) grains were given various processing treatments like malting, germination, blanching, pressure cooking and roasting to reduce the anti-nutritional factors. The most efficacious processing treatment variant is then further used for development of muffins. In the present study, malting resulted in 54.6 % reduction in Phytic acid and 51.2 % reduction in tannic acid respectively. Therefore finger millets were malted by optimizing the sprouting time for 120 h, at ambient temperature and the flour was obtained for development products. Functional muffins were developed and standardized from finger millet malt. The raw materials traditionally referred to as essential in muffin manufacturing, i.e. and refined flour, was targeted for removal or reduction. Proximate analysis and chemical composition of wheat flour, finger millet flour, finger millet malted flour as well muffins developed from these flours respectively reveled that malting increases the bio accessibility of micronutrients. Muffins were prepared and standardized for two variations i.e. 60 % and 90 %. The mean scores, textural and proximate analysis for control and two experimental variations for muffins were analyzed statistically at 5% significance level.
- by Santosh Satya and +1
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- Chemical Engineering, Food, Nutrient Content, Scientific Knowledge
In order to know the nutritional value of almendron seed (Terminalia catappa Linn) and to determine its nutrient content differences, seeds from the cities of Barquisimeto, Guanare, Mérida and Trujillo were analyzed. Measures of central... more
In order to know the nutritional value of almendron seed (Terminalia catappa Linn) and to determine its nutrient content differences, seeds from the cities of Barquisimeto, Guanare, Mérida and Trujillo were analyzed. Measures of central tendency and inferential analysis (ANOVA) were used. The protein, fat and caloric values of seeds did not show any statistical significant differences whereas the total
Mead (honey-wine) results from the alcoholic fermentation of diluted honey using a wine yeast strain. However, mead elaboration can be hampered by several problems, including delayed or arrested fermentation, production of an unpleasant... more
Mead (honey-wine) results from the alcoholic fermentation of diluted honey using a wine yeast strain. However, mead elaboration can be hampered by several problems, including delayed or arrested fermentation, production of an unpleasant aroma, poor quality and inconsistency of the final product. These difficulties are due to honey’s low nutrient content, its natural antifungal components, and the inability of the yeast strain to adapt to these unfavourable growth conditions. In this study, we evaluated the results of adding pollen at concentrations ranging from 10 to 50 g/l as a fermentation activator to improve the fermentation kinetic and the quality of meads. The effect of pollen addition on the honey must, fermentation kinetics, physicochemical characteristics, aroma profiles and sensorial aspects of the obtained meads were evaluated. The results showed that pollen addition improved fermentation rates, alcohol yields, and the final characteristics of meads. An increase in the volatile contents of the meads and an improved sensory profile was observed with pollen addition; however, this improvement was not correlated with the concentration of pollen. The adequate dose of pollen was determined by the final characteristics and sensory profile of the meads.► Pollen could be a good and appropriate activator of alcoholic fermentation in the production of mead. ► Pollen addition improved fermentation rates, alcohol yields and the final characteristics of meads. ► An increase in the volatile contents of the meads and an improved sensory profile was observed with pollen addition; however, this improvement was not correlated with the concentration of pollen. ► The adequate dose of pollen was determined by the final characteristics and sensory profile of the meads. ► The addition of 30 g/hl of pollen is the dose most appropriate because, besides giving mead better accepted, would mean less use of pollen at industrial level.
The nutritional ecology of macroherbivores in seagrass meadows and the roles of grazing by urchins, fishes and green turtles in tropical systems and waterfowl in temperate systems are discussed in this review. Only a few species of... more
The nutritional ecology of macroherbivores in seagrass meadows and the roles of grazing by urchins, fishes and green turtles in tropical systems and waterfowl in temperate systems are discussed in this review. Only a few species of animals graze on living seagrasses, and apparently only a small portion of the energy and nutrients in seagrasses is usually channeled through these herbivores. The general paucity of direct seagrass grazers may be a function of several factors in the composition of seagrasses, including availability of nitrogen compounds, presence of relatively high amounts of structural cell walls, and presence of toxic or inhibitory substances. The macroherbivores, however, can have a profound effect on the seagrass plants, on other grazers and fauna associated with the meadow, and on chemical and decompositional processes occurring within the meadow. Grazing can alter the nutrient content and digestibility of the plant, as well as its productivity. Removal of leaf material can influence interrelations among permanent and transient faunal residents. Grazing also interrupts the detritus cycle. Possible consequences of this disruption, either through acceleration or through decreased source input, and the enhancement of intersystem coupling by increased export and offsite fecal production, are discussed. The extent and magnitude of these effects and their ecological significance in the overall functioning of seagrass meadows only can be speculated, and probably are not uniform or of similar importance in both tropical and temperate seagrass systems. However, areas grazed by large herbivores provide natural experiments in which to test hypotheses on many functional relations in seagrass meadows.
- by Ellen Graber and +1
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- Pepper, Plant Nutrition, Biological Sciences, Environmental Sciences
Relationship among the DRIS Index, DRIS Nutrient Balance Index, leaf nutrient content and coffee yield in Venezuela The relationship between yield and the DRIS index (IN-DRIS), DRIS Nutrient Balance Index (IBN-DRIS) and leaf nutrient... more
Relationship among the DRIS Index, DRIS Nutrient Balance Index, leaf nutrient content and coffee yield in Venezuela The relationship between yield and the DRIS index (IN-DRIS), DRIS Nutrient Balance Index (IBN-DRIS) and leaf nutrient content from a high yielding coffee population (9.657 kg by tree) was studied. Such relations were studied on 1,122 trees of Caturra and Catuai varieties, collected at different altitudes in Lara, Yaracuy, Trujillo and Portuguesa States, in Venezuela. The potassium and phosphorus IN-DRIS were the ones that showed the highest correlation with the foliar nutrient content in the studied population. However, results did not allow establishing a reliable equation to predict yield using the three studied variables. The biannual alternance of production was pointed out as responsible for the lack of relationship.
This study was conducted to evaluate the physical, chemical, and mineralogical characteristics of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Four sites along a catena were selected at an elevation... more
This study was conducted to evaluate the physical, chemical, and mineralogical characteristics of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Four sites along a catena were selected at an elevation of 75-112 m above sea level with an average annual rainfall of 3,000 mm and an average temperature of 28°C. Results indicate that the soils are deep, clayey, and reddish in color, which is indicative of the advanced stage of soil development. They also posses excellent physical condition (friable and highly porous) although they are plastic and sticky when wet as is usual for clayey soils. In terms of chemical characteristics, the soils are acidic with low CEC values and generally low in organic matter and nutrient contents. The clay mineralogy of the soils is dominated by halloysite and kaolinite with minor amounts of goethite and hematite, and they also have generally high dithionite-extractable Fe contents confirming the advanced stage of their development. The soils in the more stable slope positions (PL-1, PL-2, and PL-4) have generally similar characteristics and appeared more developed than the one in the less stable position (PL-3). The most important pedogenic processes that formed the soils appear to be weathering, loss of bases and acidification, desilification, ferrugination, clay formation and translocation, and structure formation. The nature of the parent rock and climatic conditions prevailing in the area as well as slope position appear to have dominant effects on the development of the soils.
Land-based abalone aquaculture in South Africa, based on the local species Haliotis midae, started in the early 1990s and has grown rapidly in the last decade, with 13 commercial farms now producing over 850 t per annum. Over 6,000 t per... more
Land-based abalone aquaculture in South Africa, based on the local species Haliotis midae, started in the early 1990s and has grown rapidly in the last decade, with 13 commercial farms now producing over 850 t per annum. Over 6,000 t per annum of kelp Ecklonia maxima are now harvested for this purpose, and some kelp beds are reaching maximum sustainable limits. Research into seaweed aquaculture as feed (Ulva and some Gracilaria) for abalone started in the late 1990s on the southeast coast (where there are no kelp beds) using abalone waste water. A growing body of evidence suggests that a mixed diet of kelp plus other seaweeds can give growth rates at least as good as compound feed, and can improve abalone quality and reduce parasite loads. A pilot scale Ulva lactuca and abalone integrated recirculation unit using 25% recirculation was designed and built on the south west coast of South Africa using one 12,000-L abalone tank containing 13,200 15 ± 2.5 g abalone, connected to two 3,000-L seaweed tanks containing an initial starting biomass of 10 kg of seaweed, replicated 3 times. In an 18-month period, there were no significant differences in abalone health or growth rates, sediment build up and composition, mobile macro fauna densities and species between the recirculation or the flow-through units. Transfer of oxygen generated by the seaweeds to the abalone tanks was poor, resulting in the recirculated abalone tanks having lower (33%) dissolved oxygen concentrations than a comparable flow-through abalone unit. Seaweed nutrient content and specific growth rates in the units were comparable to seaweeds cultivated in fertilized effluent (SGR = 3.2 ± 3.4%.day−1; Yield = 0.2 ± 0.19 kg.m2.day−1). Indications were that at this low recirculation ratio the seaweeds in the units were nutrient limited and that there were no negative effects to the abalone being cultivated in such a recirculation unit at this recirculation ratio.
- by Christian Zurbrügg and +1
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- Thermodynamics, Soil, Water, Agriculture
- by Neelotpal Sen Sarma and +1
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- Soil, Carbon, Biomass, Recycling