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005			20260818095254.0
008			111010s1992 th uu|m rtt 0| a1eng d
035			_a.b10230749
099		9	_aAIT Thesis no. AE-92-27
100	0		_aSujjat-Al-Azad
245	1	4	_aThe effects of light intensity, fertilization and water depth on the production of Lemna
260			_aBangkok : _bAsian Institute of Technology, _c1992
300			_a106 leaves
490	1		_aThesis ; _vno. AE-92-27
500			_aA thesis submitted to the partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development
502			_aThesis (M.sc.) - Asian Institute of Technology, 1992
520			_aThree experiments were conducted in an outdoor system of fifteen circular concrete tanks each of 2.07m~ area, to investigate the effects of light intensity, urea- N and triple super phosphate- P, and water depth on the production and nutrient uptake of Lemna perpusilla. Experiment 1 involved a fertilization rate of 0.25g N/m3 /day and a water depth of 1.0m at 301., 401., 651., 80/. and 100/. ambient light; Experiment 2 involved a 30/. ambient light in O. lg, 0.2g, 0.3g, 0.4g and 0.5g N/m3 /day (N:P ratio 2:1) in a depth of 1.0m; and Experiment 3 involved a fertilization rate of 0.25g N/m3 /day and with 30/. ambient light, and 0.2m, 0.4m, 0.6m, O.Bm and 1.0m water depths of tanks. The highest extrapolated net yields in the three experiment were, 3.486 tonnes/ha/yr in Experiment 1 with 0.25g N/m3 / day in 1.0m depth and with a 30/. ambient 1 ight when photosynthetic active radiation was 3 to 11 Umol/m-2/s-.1.; and with a fertilization rate of 0.25g N/m3 /d and with 30/.light, in a depth of 0.4m it was 3.515 tonnes/ha/yr, and in Experiment 2 with a varying rates of fertilization and 30/. light, the yield was 3.78 tonnes/ha/yr in the lowest concentration rate of O.lg N/m3 /day . Nitrogen contents in Lemna were not significantly different (p>0.05), but phosphorus contents were significantly different (p<0.05) in the first two experiments. The experiment with depth showed significance differences in nitrogen and phosphorus contents in Lemna (p<0.05). Nitrogen and phosphorus contents increased with nutrient loading rate. Most of the nitrogen added remained in the water in all experiments, except in the experiment with a fertilization rate of O.lg N/m3 /day, with 30/. ambient light; and 0.4m tank in an experiment with 0.25g N/m3/day and 30/. light, where the largest amounts, 55.79/. and 52.8/. respectively, were taken up by Lemna. On the other hand, phosphorus always showed the highest accumulation in the sediments in all experiments, except for the nutrient loading rate and depth mentioned above, where Lemna contained the largest amoL1nt of added nitrogen, 39.12/. and 42.21., respectively.
650		0	_aLemna
700	1		_aEdwards, Peter, _eChairperson
700	1		_aLittle, David C., _eExamination Committee
700	1		_aYakupitiyage, Amararatne, _eExamination Committee
710	2		_aThe British Council, _eScholarship Donor
810	2		_aAsian Institute of Technology. _tThesis ; _vno. AE-92-27
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B16540
907			_a.b10230749 _bmnait _cs
902			_a240329
998			_b2 _c951012 _dm _ea _fs _g4
945			_lmnait
945			_lmnait
945			_lmnarc
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942			_c40
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