We investigated the effects of various anthropogenic factors on urban soil properties in subtropical, coastal Tampa, FL, USA. Specifically, we explored the influence of (i) urbanization as measured by land use, land cover, population density and years since urban development and (ii) socioeconomic conditions as reflected in household income and property values on bulk density (BD) and several key soil chemical properties. Results indicate that Tampa’s urban soils were affected to varying degrees by these factors with chemical properties being more variable than BD. Across land uses significant differences were found for Mehlich‐1 (M1) extractable P, Ca and Na. A similar trend was observed for land‐cover classes, although significant differences were also found for pH and M1‐Cu. Soil properties had no statistically significant relationship with population density. However, time since urbanization did with M1‐P and Na varying significantly across age categories. For our socioeconomic analyses, M1‐K and Mg levels differed significantly by household income while pH, P, Ca and Na values differed significantly by property value. Overall, our findings indicate that despite their inherent heterogeneity, there are identifiable patterns among subtropical coastal urban soil properties. We suggest that a more thorough understanding of these patterns and their drivers is an essential first step towards developing soil management strategies aimed at maintaining environmental quality and ecosystem services in subtropical cities. 相似文献
A study on the growth and reproductive performance of two rabbit breeds was undertaken. Data on 588 kits and 97 does of California White and 574 kits and 90 does of New Zealand White rabbits reared under hot and humid environment in Ghana were taken. The reproductive performance of the two breeds, in terms of litter size at birth and weaning, litter weight at birth and weaning, kindling interval, age at sexual maturity, and gestation length as influenced by breed, season of kindling (rainy and dry), year of kindling (2005–2012), and parity (first to sixth and over) were determined. The performance of California White in terms of litter size at birth, at weaning, kit weight at birth, and age at first kindling was 5.9?±?0.2, 4.6?±?0.1, 54.7?±?0.4 g, and 159.8?±?0.2 days, respectively. That of New Zealand White was 5.9?±?0.1, 5.1?±?0.1, 55.2?±?1.0 g, and 159.9?±?0.2 days, respectively. The results obtained also showed a significant breed effects on kit weight at birth, litter weight at weaning, and mortality; whereas no significant differences (p?>?0.05) were observed between the two breeds regarding the other traits measured. Parity had significant effects (p?<?0.05) on all the growth and reproductive parameters measured with the exception of age at first kindling. Year of kindling also had significant effect on litter weight at birth, kit weight at birth, and at weaning (p?<?0.05) but did not have any significant effect on the age at sexual maturity and mortality. Season also had significant (p?<?0.05) effects on kit weight at birth, gestation length, kindling interval, and mortality with better performance experienced during the rainy season.
1. Two experiments were conducted to develop naked neck (Na/na) and normal feathered (na/na) crossbreds and compare their growth performance, linear body measurements and carcass characteristics in the first and second filial generations.
2. In the first experiment, 4 indigenous naked neck males (Na/na) were mated to 36 Lohmann commercial females (na/na) in a ratio of 1:9. The two genotypes (Na/na, na/na) were allocated randomly according to batches of hatch, sire lines and sex to three different villages.
3. In the second experiment, 10 males and 100 females of F1Na/na birds were selected and mated inter se in a ratio of 1:10. The three genotypes (Na/Na, Na/na and na/na) were compared in a randomised complete block design experiment, with the three villages, hatch and sex as blocks and the three genotypes as treatments. F1Na/na birds had significantly higher (P < 0.05) feed conversion ratio, body weight, body weight gain, linear body measurements, survivability and carcass yield than their na/na counterparts.
4. In the F2 generation, Na/Na and Na/na birds had significantly higher (P < 0.05) feed conversion ratio, body weight, body weight gain, linear body measurements, survivability and carcass yield compared to their na/na counterparts.
5. The birds showing the naked neck phenotype appeared to show superior performance compared to normal feathered birds and could be exploited for potential utilisation in local poultry production. 相似文献
A thin layer chromatographic cleanup development with benzene-hexane (3+1) effectively removed lipids and some contaminants from mixtures of mycotoxins in corn oil, olive oil, peanut oil, soybean oil, and seed extracts. A second development in the same direction as the first, using toluene-ethyl acetate-formic acid (6+3+1) or benzene-acetic acid (9+1), separated the mycotoxins. Satisfactory separation was achieved for commercial oils spiked with sterigmatocystin, zearalenone, ochratoxins A, B, and C, and aflatoxins B1, B2, G1, and G2. This technique permits detection of 5 ppb aflatoxin B1 in corn. 相似文献
Japanese stiltgrass (Microstegium vimineum), an exotic invasive plant, is native to Southeast Asia. This study was conducted to determine the chemical composition of Japanese stiltgrass as well as soil and landscape characteristics that correlate with invasion of Japanese stiltgrass around Lake Issaqueena in the upper Piedmont of South Carolina. Geographic Information Systems (GISs) and Light Detection and Ranging (LiDAR) were used to determine the spatial pattern of invasion with respect to the aspect, slope, canopy cover, soils, and distance to roads and trails. Japanese stiltgrass was distributed on both sides of Lake Issaqueena in Pacolet and Madison soil map units (Fine, kaolinitic, thermic Typic Kanhapludults) on the average slopes of 21%, but it was particularly common on the eastern shore of the lake in low-lying wet and shaded areas (mean canopy cover 51%). In addition, invasion by Japanese stiltgrass was correlated with the proximity to roads and trails. Plant tissue analysis revealed many differences in the distribution of macronutrients, macrominerals, and micronutrients in the leaves, stems, and roots of Japanese stiltgrass, although those differences were not always statistically significant. Concentrations of nitrogen (N), phosphorus (P), and calcium (Ca) were the highest in leaves while zinc (Zn) concentrations were the highest in stems and concentrations of magnesium (Mg), copper (Cu), manganese (Mn), iron (Fe), and sodium (Na) tended to be higher in roots. Carbon (C), sulfur (S), and potassium (K) concentrations were generally higher in above-ground tissues versus roots. Soil chemical analysis revealed no statistical differences between control and invaded plots. Our findings suggest that watershed areas surrounding lakes may be particularly susceptible to the invasion of Japanese stiltgrass due to their microclimates, low-lying wet pathways for seed distribution and recreational uses. 相似文献
