A mathematical approach for estimating light absorption by a crop from continuous radiation measurements and restricted absorption data

• Published in: Computers and electronics in agriculture Vol. 22; no. 1; pp. 71 - 81
• Main Authors: Zanetti, P, Delfine, S, Alvino, A
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.1999; Elsevier
• Subjects: ABSORCION; ABSORPTION; Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Biological and medical sciences; CANOPY; COUVERT; CRECIMIENTO; CROISSANCE; Crop climate. Energy and radiation balances; CUBIERTA DE COPAS; DROUGHT STRESS; ESTRES DE SEQUIA; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; GROWTH; HELIANTHUS ANNUUS; Light absorption; MODELE; Modeling; MODELOS; Plant growth; RADIACION SOLAR; RADIATION SOLAIRE; REGIME HYDRIQUE DU SOL; REGIMEN HIDRICO DEL SUELO; Salt stress; SALT TOLERANCE; SOIL WATER REGIMES; SOLAR RADIATION; STRESS DU A LA SECHERESSE; Sunflower; TOLERANCE AU SEL; TOLERANCIA A LA SAL; Water stress; Campania; Italy; Europe; Salt stress; Light absorption; Plant growth; Sunflower; Modeling; Water stress; Interpolation formula; Compositae; Oil plant(vegetal); Salinity; Radiation absorption; Helianthus annuus; Meteorological station; Water regime; Dicotyledones; Angiospermae; Agrometeorology; Spermatophyta; Continuous measurement; Mediterranean region; Mathematical model; Solar radiation; Computer aid; Phytoclimate; Canopy(vegetation); Leaf area index
• ISSN: 0168-1699; 1872-7107
• DOI: 10.1016/S0168-1699(99)00002-2

A sunflower ( Helianthus annuus L.) crop was grown with four different water regimes to obtain different canopy growth and light absorption capability. The incoming solar radiation was recorded by an agrometeorological field station, while the percentage absorbed by the crop was measured by a ceptometer at four times and on a quasi-daily basis over the all reproductive phases. Triangulation on these data points and cubic interpolation was used to model the radiation absorbed by the canopies over time. In order to validate this approach, the procedure was also applied to a small subset of the data. Numerical quadrature based on an adaptive recursive Simpson’s rule was used to integrate the radiation absorbed by the canopies. The numerical quadrature was applied (i) to the whole data collected, represented by a cubic two-dimensional spline interpolation function, and (ii) to the interpolated values obtained from the restricted data set. The differences between (i) and (ii) for the four water regimes varied from 3.6 to 5.2% approximately. These comparisons demonstrated the potential of a restricted data interpolation model for investigating the complex phenomena of light interception by canopies with different plant structure.