Influence of diesel spillage on the productivity of ipomoea batatas and lactuca sativa
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Date
2013
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Publisher
University of Zululand
Abstract
The effects of diesel contamination in soil on the germination, growth and dry matter partitioning in Lactuca sativa (crisp head variety) and Ipomoea batatas (dagga variety) were studied at two diesel concentration ranges 0-30 and 0-6 ml/kg soil. The first experiment tested the effects of diesel concentration and age of diesel contamination in soil on the germination of L. sativa and I. batatas. The second experiment investigated the effects of diesel contamination in soil on the growth and dry matter partitioning in I. batatas and L. sativa.
The effects of diesel concentration in soil contamination on the germination of L. sativa and I. batatas varied with the diesel concentration and the age of diesel contamination in the soil. Diesel inhibited the germination of L. sativa and I. batatas in a concentration dependent manner, showing increased inhibition with increasing concentration of diesel contamination in the soil. Also, the critical concentration of diesel for toxicity on the germination of L. sativa and I. batatas increased with the aging of diesel contamination in soil. However, the influence of diesel contamination in soil on the germination of the two species diminished with the age of diesel contamination in soil, suggesting possible reduction in diesel toxicity over time. The germination of L. sativa was more affected by diesel contamination in soil than that of I. batatas.
The result of experiment two indicated that, after 14 weeks of growth, the plant height, number of leaves, stem lengths, root lengths and the leaves chlorophyll content of L. sativa and I. batata, were highly negatively correlated with diesel concentration in soil contamination. The effects of diesel contamination in the soil on dry matter partitioning of the two species also varied with diesel concentration in soil contamination. At low diesel concentration in soil contamination in soil contamination (0-6 ml/kg soil), allocation of dry matter to the shoot system was favoured resulting in high shoot: root ratio of 4.54 and
12.91 for L. sativa and I. batatas respectively. However, at diesel concentration in soil contamination 0-30 ml/kg, allocation of dry matter to the root was favoured, an indication of the effort of L. sativa and I. batatas to survive the phytotoxic effects of diesel hydrocarbons in the soil. The effects of diesel contamination in soil on the germination and growth of Ipomoea batatas were more pronounced on the germination and growth of Lactuca sativa.
It can be concluded that, the phytotoxicity of diesel contamination in soil on the germination and growth of L. sativa is markedly stronger than the phytotoxity of diesel on the germination and growth of I. batatas.
Description
A dissertation submitted to the Department of Agriculture in fulfillment of the requirements for the Degree Master of Science and Faculty of Science and Agriculture at the University of Zululand, South Africa, 2013.
Keywords
Diesel production, Diesel contamination