Leaf dispersion and light partitioning in three‐dimensionally digitized tall fescue–white clover mixtures

A three-dimensional digitizing method was used to assess the canopy structure of six Festuca arundinacea (FA)‐ Trifolium repens (TR) mixtures during the installation stage. Virtual canopy images were synthesized and used to derive light interception and partitioning between species. Computations from images were compared with a simple light model based on Beer’s law, in order to analyse within- and between-species foliage dispersion. The total leaf area index of the mixtures ranged from 0·6 to 4·5. The fraction of FA foliage overtopping TR was 9‐30%. The mean inclination of FA and TR was 66 and 57 ° , respectively. Within-species dispersion parameters of FA and TR were about 0·8 and 1·0, namely clumped and random foliage dispersion, respectively. Although FA was sown in rows, between-species dispersion was random. Lower leaf inclination and lesser clumping in TR compensated foliage overtopping by FA, so that light partitioning between FA and TR (about 80 and 20%, respectively) was similar to the species contribution to total canopy foliage. Since between-species dispersion was random, a simple two-layer light model based on Beer’s law provided correct estimations of light partitioning (RMSE = 0·05), although light interception by FA was slightly overestimated because of its clumped dispersion.

[1]  M. Caldwell,et al.  Plant Architecture and Resource Competition , 1987 .

[2]  J. Monteith,et al.  The Radiation Regime and Architecture of Plant Stands. , 1983 .

[3]  B. Marshall,et al.  Radiation interception and growth in an intercrop of pearl millet/groundnut , 1983 .

[4]  C. T. Wit.  Photosynthesis of leaf canopies , 1965 .

[5]  Hervé Sinoquet,et al.  Leaf orientation and sunlit leaf area distribution in cotton , 1997 .

[6]  H. Sinoquet,et al.  A theoretical analysis of radiation interception in a two-species plant canopy. , 1991, Mathematical biosciences.

[7]  R. W. Willey,et al.  Physiological basis for yield advantage in a sorghum/groundnut intercrop exposed to drought. 1. Dry-matter production, yield, and light interception , 1987 .

[8]  J. Frame,et al.  Agronomy of White Clover , 1986 .

[9]  M. Monsi.  Uber den Lichtfaktor in den Pflanzengesellschaften und seine Bedeutung fur die Stoffproduktion , 1953 .

[10]  Hervé Sinoquet,et al.  Radiation Interception, Partitioning and Use in Grass –Clover Mixtures , 1996 .

[11]  L. H. Allen,et al.  Radiation and microclimate relationships in multiple cropping systems. , 1976 .

[12]  Akira Osawa,et al.  Measurement of three‐dimensional structure of plants with a simple device and estimation of light capture of individual leaves , 1998 .

[13]  B. Trenbath,et al.  Biomass Productivity of Mixtures , 1974 .

[14]  Danny Lo Seen,et al.  PAR extinction in shortgrass ecosystems: effects of clumping, sky conditions and soil albedo , 2000 .

[15]  H. Sinoquet,et al.  Light interception and partitioning in a shrub/grass mixture , 1995 .

[16]  Martin J. Kropff,et al.  Modelling and measuring vertical light absorption within grass-clover mixtures , 1999 .

[17]  R. Bonhomme.  Beware of comparing RUE values calculated from PAR vs solar radiation or absorbed vs intercepted radiation , 2000 .

[18]  J. Ross.  The radiation regime and architecture of plant stands , 1981, Tasks for vegetation sciences 3.

[19]  D. J. Fitter,et al.  STAND STRUCTURE AND LIGHT PENETRATION , 1980 .

[20]  S. Flint,et al.  Plant competition for light analyzed with a multispecies canopy model , 1990, Oecologia.

[21]  Pauline Stenberg.  Penumbra in within-shoot and between-shoot shading in conifers and its significance for photosynthesis , 1995 .

[22]  Reinhart Ceulemans,et al.  Measurement of gap fraction of fractal generated canopies using digitalized image analysis , 1993 .

[23]  R. Myneni,et al.  A review on the theory of photon transport in leaf canopies , 1989 .

[24]  H. Sinoquet,et al.  Characterization of the Light Environment in Canopies Using 3D Digitising and Image Processing , 1998 .

[25]  P. Cruz,et al.  Efecto del nitrógeno y de la presencia de trébol blanco sobre festuca alta , 1991 .

[26]  A.R.G. Lang,et al.  Leaf orientation of a cotton plant , 1973 .

[27]  M. A. Wolf,et al.  Portable monitor for solar radiation that accumulates irradiance histograms for 32 leaf-mounted sensors , 1985 .

[28]  G. T. Barthram,et al.  The effects of management and plant variety on the composition, vertical structure and stock‐carrying capacity of Lolium perenne/Trifolium repens pastures , 1994 .

[29]  R. W. Willey.  Intercropping Its Importance And Research Needs Part 1. Competition And Yield Advantages Vol-32 , 1979 .

[30]  H. Sinoquet,et al.  Measurement and visualization of the architecture of an adult tree based on a three-dimensional digitising device , 1997, Trees.

[31]  H. Sinoqueta,et al.  Comparison of models for daily light partitioning in multispecies canopies , 2000 .

[32]  H. Sinoquet,et al.  Assessing the Geometric Structure of a White Clover ( Trifolium repens L.) Canopy using3-D Digitising , 2000 .

[33]  M. Begon,et al.  A model of competition , 1975, Oecologia.

[34]  Jane Woledge,et al.  Growth and photosynthesis of tall and short cultivars of white clover with tall and short grasses , 1992 .

[35]  P. Prusinkiewicz,et al.  Virtual plants: new perspectives for ecologists, pathologists and agricultural scientists , 1996 .

[36]  Fernando Valladares,et al.  Tradeoffs Between Irradiance Capture and Avoidance in Semi-arid Environments Assessed with a Crown Architecture Model , 1999 .

[37]  Eric Haines,et al.  Essential ray tracing algorithms , 1989 .

[38]  G. Rimmington.  A Test of a Model for Light Interception by Mixtures , 1985 .

[39]  A. Lang,et al.  An instrument for measuring canopy structure , 1990 .

[40]  Glyn M. Rimmington,et al.  A model of the effect of interspecies competition for light on dry-matter production , 1984 .

[41]  S. Azam-Ali,et al.  Light Use, Water Uptake and Performance of Individual Components of a Sorghum/Groundnut Intercrop , 1990, Experimental Agriculture.

[42]  H Sinoquet,et al.  Canopy structure and light interception in Quercus petraea seedlings in relation to light regime and plant density. , 2001, Tree physiology.

[43]  J. W. Wilson,et al.  Stand Structure and Light Penetration. I. Analysis by Point Quadrats , 1965 .

[44]  R. McMurtrie,et al.  A Model of Competition between Trees and Grass for Radiation, Water and Nutrients , 1983 .

[45]  Hervé Sinoquet,et al.  RATP: a model for simulating the spatial distribution of radiation absorption, transpiration and photosynthesis within canopies: application to an isolated tree crown , 2001 .

[46]  T. Nilson.  A theoretical analysis of the frequency of gaps in plant stands , 1971 .

[47]  Bruno Andrieu,et al.  The nested radiosity model for the distribution of light within plant canopies , 1998 .

[48]  H. Sinoquet,et al.  Estimating the three-dimensional geometry of a maize crop as an input of radiation models: comparison between three-dimensional digitizing and plant profiles , 1991 .

[49]  A. Marshak,et al.  Calculation of canopy bidirectional reflectance using the Monte Carlo method , 1988 .