Agricultural and Forest Meteorology 104 2000 25–47
Utilisation of light and water in tropical agriculture
q Colin Black
a,∗
, Chin Ong
b,1
a
University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
b
International Centre for Research in Agroforestry, Nairobi, Kenya
Abstract
The resource capture approach developed by John Monteith has been applied in studies of a wide variety of plant species and cropping systems in the tropics over the past 18 years. The purpose of this review is to highlight the progress made
and the new challenges which lie ahead. The foundation for this approach was the establishment of ‘response surfaces’ for the development and growth of tropical crops using controlled-environment facilities. The concepts of light interception and
thermal time developed were then used to investigate the mechanisms responsible for overyielding in intercropping systems and genotypic differences in the drought adaptation of crops in the semi-arid tropics. The most significant achievements were
in the understanding of temporal and spatial complementarity in intercropping and agroforestry systems and the development of plant growth models. More recently, the same concepts have been extended to the capture of below-ground resources in
agroforestry systems and rain forests. The most serious remaining challenge is to extend this approach to studies of complex multispecies systems in the humid tropics. © 2000 Elsevier Science B.V. All rights reserved.
Keywords: Agroforestry; Intercropping; Resource capture; Light; Water; Temperature
1. Introduction
Although John Monteith’s considerable contri- bution to environmental physics and the study of
plantenvironment interactions is universally acknow- ledged Campbell, 2000, his concept of resource
capture Monteith, 1977a, which has had a major in- fluence on the development of tropical agricultural re-
search, is equally important but less well-documented. Our association with John Monteith JLM began in
Sutton Bonington in the late 1970s, during the Over- seas Development Administration ODA project to
examine the ‘Microclimatology of Tropical Crops’;
q
Invited paper for ASA-CSSA-SSSA Annual Meetings, 3–8 November, Indianapolis, USA.
∗
Corresponding author. Fax: +115-9516334. E-mail addresses: colin.blacknottingham.ac.uk C. Black,
c.ongcgnet.com C. Ong
1
Fax: +254-2-521001.
this project continued for 10 years and formed the basis for a book entitled ‘The Physiology of Tropical
Crop Production’ Squire, 1990. Our first practical problem was how to prevent the pearl millet grow-
ing through the vents of the controlled environment glasshouses due to the long days of the British sum-
mer These glasshouses are still in use today after being updated with state-of-the-art computer control
of environmental conditions.
The ambitious objective of this project was to un- couple the effects of the major elements of weather,
such as temperature, atmospheric saturation deficit and drought stress, with the ultimate goal of developing
general principles of microclimatology governing the behaviour of tropical crops and then applying them to
the tropics Monteith et al., 1983. Two important con- cepts became the cornerstones for the interpretation
of experimental results. The first was JLM’s concept of resource capture, which he elegantly demonstrated
0168-192300 – see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 1 9 2 3 0 0 0 0 1 4 5 - 3
26 C. Black, C. Ong Agricultural and Forest Meteorology 104 2000 25–47
by showing that accumulated dry matter production of a wide range of crops and orchards in Britain was
linearly related to accumulated intercepted solar radi- ation Monteith, 1977a. The second was the applica-
tion of the thermal time concept to describe the effects of temperature on crop development Monteith, 1979.
These concepts were tested in the tropics in close collaboration with the International Crop Research
Institute for the Semi-Arid Tropics ICRISAT, Hy- derabad, India, where JLM was Director of the Re-
source Management Programme between 1987 and 1991, to assist in the more practical problem of es-
tablishing genotype–environment interactions for mil- let and groundnut Williams, 2000 and determine the
mechanisms responsible for overyielding in intercrop- ping systems Marshall and Willey, 1983; see also re-
views by Fukai and Trenbath, 1993; Ong and Black, 1994; Azam-Ali, 1995. Today these concepts have
been applied throughout the tropics and subtropics and such studies are no longer confined to international
centres; for example, Vijaya Kumar et al. 1996 ap- plied these concepts to castor beans at the Central Re-
search Institute for Dryland Agriculture, Hyderabad, India. JLM’s resource capture concept has also been
applied in forestry research Landsberg, 1986; Can- nell et al., 1987, crop simulation models Ritchie and
Otter, 1985; Jones and Kiniry, 1986, as a tool for biomass prediction in agronomic research Sinclair
et al., 1992 and in remote sensing Christensen and Goudriaan, 1993.
Recently, the same approaches have been used to unravel the more complex interactions between trees
and crops in agroforestry systems in studies of both above- and below-ground interactions Ong et al.,
1991; Ong and Black, 1994. Initial findings indicated that there are critical differences between intercrop-
ping and agroforestry which are apparently linked to the relative importance of below-ground interactions
Ong et al., 1996. Even more formidable difficulties were encountered when these essentially agronomic
plot size findings were extrapolated to farm and land- scape levels since the extensive lateral growth of tree
roots may lead to their extension across farm bound- aries or between adjacent experimental plots Hauser,
1993; Rau et al., 1993.
In this review, we describe how John Monteith’s concepts of resource capture and thermal time have
been applied in tropical agricultural research and focus on recent attempts to apply these concepts
to agroforestry. Finally, we highlight some of the progress made and the new challenges ahead.
2. Principles of radiation interception and use
