Root architecture in relation to tree-soil-crop interactions and shoot pruning in agroforestry
- 263 Downloads
Desirable root architecture for trees differs between sequential and simultaneous agroforestry systems. In sequential systems extensive tree root development may enhance nutrient capture and transfer to subsequent crops via organic pools. In simultaneous systems tree root development in the crop root zone leads to competition for resources.
Fractal branching models provide relationships between proximal root diameter, close to the tree stem, and total root length or surface area. The main assumption is that a root branching proportionality factor is independent of root diameter. This was tested in a survey of 18 multipurpose trees growing on an acid soil in Lampung (Indonesia). The assumption appeared valid for all trees tested, for stems as well as roots. The proportionality factor showed a larger variability in roots than in stems and the effects of this variabilily should be further investigated. A simple index of tree root shallowness is proposed as indicator of tree root competitiveness, based on superficial roots and stem diameter.
Pruning trees is a major way to benefit from tree products and at the same time reduce above-ground competition between trees and crops. It may have negative effects, however, on root distribution and enhance below-ground competition. In an experiment with five tree species, a lower height of stem pruning led to a larger number of superficial roots of smaller diameter, but had no effect on shoot:root ratios or the relative importance of the tap root.
Key wordscompetition fractal multipurpose trees root methods root pattern
Unable to display preview. Download preview PDF.
- Coster Ch (1932) Wortelstudiën in de tropen (Root studies in the tropics). I. De jeugdontwikkeling van het wortelstelsel van een zeventigtal boomen en groenbemesters (Early development of the root system of seventy trees and green manure species). Korte Meded vh Boschb Proefst no. 29Google Scholar
- Coutts MP (1983) Root architecture and tree stability. Plant and Soil 71:171–188Google Scholar
- De Foresta H and Michon G (1994) Agroforests in Sumatra, where ecology meets economy. Agroforestry Today 6(4):12–13Google Scholar
- De Reffye P, Houllier F, Blaise F, Barthelemy D, Dauzat J. and Auclair D (1995) A model simulating above- and below-ground tree architecture with agroforestry applications. Agroforestry Systems (this issue)Google Scholar
- Fitter AH and Stickland TR (1992) Fractal characterization of root architecture. Functional Ecology 6:632–635Google Scholar
- Hairiah K, Van Noordwijk M, Santoso B and Syekhfani MS (1992) Biomass production and root distribution of eight trees and their potential for hedgerow intercropping on an ultisol in Lampung. AGRIVITA 15:54–68Google Scholar
- Kooistra MJ and Van Noordwijk M (1995) Soil architecture and distribution of organic carbon. In: Carter MR (ed) Structure and Organic Carbon Storage in Agricultural Soils. Advances in Soil Science (in press)Google Scholar
- Kuiper LC, Bakker AJJ and Van Dijk GJE (1990) Stem and crown parameters related to structural root systems of Douglas fir. Wageningen Agric Univ Papers 90-6: 57–67Google Scholar
- Le Roux Y (1994) Mise en place de l'architecture racinaire d'Hevea brasiliensis, étude comparée du semis et de la microbouture. Thesis doctorat, Université d'Aix Marseille III, Aix Marseille, FranceGoogle Scholar
- Mandelbrot BB (1983) The Fractal Geometry of Nature. Freeman, New York, NY, USAGoogle Scholar
- Ong CK and Khan AAH (1993) The direct measurement of water uptake by individual tree roots. Agroforestry Today 5(4):2–4Google Scholar
- Pagès, L, Le Roux Y and Thaler P, 1995) Modélisation de l'architecture racinaire. Plantations, Recherche, Développement 1995(1):19–34Google Scholar
- Pagès L and Aries F (1988) SARAH: Modèle de simulation de la croissance, du développement et de l'architecture des systèmes racinaires. Agronomie 8:889–896Google Scholar
- Prusinkiewicz P and Lindenmayer A (1990) The Algorithmic Beauty of Plants. Springer-Verlag, Berlin, Germany, 302 ppGoogle Scholar
- Shinozaki K, Yoda K, Hozumi K and Kira T (1964) A quantitative analysis of plant form — the pipe model theory. Japanese Journal of Ecology 14:97–105Google Scholar
- Soumaré A, Groot JJR, Koné D and Radersma S (1994) Structure spatiale du système racinaire de deux arbres du Sahel:Acacia seyal andSclerocaryea birrea. Rapport PSS no. 5, Wageningen. The Netherlands, 45 ppGoogle Scholar
- Spek LY and Van Noordwijk M (1994) Proximal root diameters as, predictors of total root system size for fractal branching models. II. Numerical model. Plant and Soil 164:119–128Google Scholar
- Van Noordwijk M, Widianto, Heinen M and Hairiah K (1991a) Old tree root channels in acid soils in the humid tropics: important for crop root penetration, water infiltration and nitrogen management. Plant and Soil 134:37–44Google Scholar
- Van Noordwijk M, Hairiah K, Syekhfani M and Flach EN (1991b)Peltophorum pterocarpa: a tree with a root distribution suitable for alley cropping. In: Persson H and McMichael BL (eds) Plant Roots and Their Environment, pp 526–532 Elsevier, Amsterdam, The NetherlandsGoogle Scholar
- Van Noordwijk M, Widianto, Sitompul SM, Hairiah K and Guritno B (1992) Nitrogen management under high rainfall conditions for shallow rooted crops: principles and hypotheses. AGRIVITA 15:10–18Google Scholar
- Van Noordwijk M, Spek LY and De Willigen P (1994) Proximal root diameters as predictors of total root system size for fractal branching models. I. Theory. Plant and Soil 164:107–118Google Scholar
- Van Noordwijk M (in press) A simple model to quantify mulch and shade effects. In Huxley PA and Ong CK (eds) Tree-Crop Interactions—a Physiological Approach, Chapter 3. CAB International, Wallingford, UKGoogle Scholar
- Van Noordwijk M and Brouwer G (1995) Roots as sinks and sources of carbon and nutrients in agricultural systems. Advances in Agroecology (in press)Google Scholar
- Van Noordwijk M, Lawson G, Groot JJR and Hairiah K (in press) Root distribution in relation to nutrients and competition. In: Huxley PA and Ong CK (eds) Tree-Crop Interactions—a Physiological Approach, Chapter 10, CAB International, Wallingford, UKGoogle Scholar