Effects of solar radiation on dry matter production of cassava (Manihot esculenta Crantz)

Llamelo, Adoracion B. (1983). Effects of solar radiation on dry matter production of cassava (Manihot esculenta Crantz) Master's Thesis, School of Land, Crop and Food Sciences, The University of Queensland.

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Author Llamelo, Adoracion B.
Thesis Title Effects of solar radiation on dry matter production of cassava (Manihot esculenta Crantz)
School, Centre or Institute School of Land, Crop and Food Sciences
Institution The University of Queensland
Publication date 1983
Thesis type Master's Thesis
Supervisor Dr. Shu Fukai
Prof. G.L. Wilson
Total pages 49
Language eng
Subjects 0701 Agriculture, Land and Farm Management
Formatted abstract
Effects of different solar radiation inputs (100, 78 and 32% full sunlight on the development of leaf area index, light interception and crop growth rate were examined using two different aged crops of cassava, cv. MAus 7. The plants were grown under favourable water and nutritional conditions in Redland Bay (lat. 27 ⁰ 37'S long. 153 ⁰ 17'E), Southeast Queensland from October 6, 1981 to February 18, 1982. Solar input treatments lasted for 35 days in January and February.

Highest leaf area indices of 7.3 and 5.4 were obtained under 100% solar input from the October (P1) and November (P2) plantings. Decreasing the solar radiation level to 78 and 32% of full sunlight slightly reduced LAI but it increased the specific leaf area.

The highest total dry matter yield of 1137 g m-2 was obtained by plants in the 100% solar input treatment established in October (135 days old) while the November planting gave 702 g m-2 at 86 days after planting. Total dry matter was most affected when light level was 32% in the younger plants. Storage root growth was more affected by reduced solar input than the top growth.

The crop growth rate increased with LAI up to 4.2 and the amount of total intercepted solar radiation. As almost all incoming radiation was intercepted during the 35 day treatment period differences in crop growth rate were mainly related to the variation in solar radiation input. During the treatment period, crop growth rates of 17.3 g m-2 d-1 was attained in the October planting and 14.3 g m -2 d-1 in the November planting. Crop growth rates were almost halved by reduction of solar input to 32% full sun level.

Higher proportion of light interception occurred in the top 20-40 cm layers of P1 and P2 plants below which horizontal flux density was very low.

Higher light extinction coefficient of around 1.0 occurred under the low light regime but despite this, the efficiency of energy conversion under the reduced solar radiation was higher than the full sunlight. Under full light, light extinction coefficient increased with age up to about 0.7 in the fully developed canopies.

Keyword Cassava
Plants -- Effect of light on
Solar radiation
Additional Notes

Spine title: Solar radiation effects on cassava.

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
Citation counts: Google Scholar Search Google Scholar
Created: Fri, 21 Oct 2011, 11:54:09 EST by Ms Christine Heslehurst on behalf of Scholarly Communication and Digitisation Service