The vertical distribution of fine roots of five tree species and maize in Morogoro, Tanzania

Jonsson, K.; Fidjeland, L.; Maghembe, J. A.; Högberg, P.

doi:10.1007/bf02344746

Cited by 95 publications

(33 citation statements)

References 8 publications

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“…Clumped distributions of tree roots within the soil, as seen in the proteoid roots of Grevillea robusta, might also reduce interspecific competition (Huxley et al, 1994). However, numerous studies have shown that most tree roots, especially those of fast-growing species, exploit the same soil depths as crop roots (Jonsson et al, 1988;Daniel et al, 1991;van Noordwijk et al, 1996), and the importance of root clumping remains uncertain.…”

Section: Introductionmentioning

confidence: 99%

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et al. 2001

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and Gliricidia sepium (Jacq.) Walp. growing in association with maize (Zea mays L.) were examined in semiarid Kenya during the long rains of 1996 and 1997. Even although tree roots penetrated more deeply than maize roots, maximum root length densities for both tree species and maize occurred in the top 200 mm of the soil profile where soil moisture was frequently recharged by rains. Populations of roots in plots containing trees were dominated by tree roots at the beginning of the growing season but because tree roots died and maize root length increased during the cropping season, amounts of tree and maize roots were similar at the end of the season. Thus, there was evidence of temporal separation of root activity between species, but there was no spatial separation of the rooting zones of the trees and crops within that part of the soil profile occupied by crop roots. Tree root length density declined with increasing distances from rows of trees and with depth in the soil profile.Although Grevillea trees were largest, plots containing G. sepium trees always contained more tree roots than plots containing G. robusta trees and Gliricidia was more competitive with maize than Grevillea. Overall, Gliricidia reduced crop yield by about 50% andGrevillea by about 40% relative to crop yield in control plots lacking trees and reductions of crop yield were greatest close to trees. There was less soil moisture in plots containing trees than in control plots. Such difference between control plots and plots containing trees were maximal at the end of the dry season and there was always less soil moisture close to trees than elsewhere in the plots. Plots containing Gliricidia trees contained less soil water than plots containing Grevillea trees.

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Section: Introductionmentioning

confidence: 99%

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“…Overall, root abundance of leucaena declined with depth; however there was not greater abundance of fine roots in the top soil (0-1 m) as reported by other authors (Jonsson et al 1988;Dhyani et al 1990;Poole, 2003). In this study, many fine roots were observed between 1-2 m depth in the soil profile.…”

Section: Effect Of Within-row Density On Rooting Patternssupporting

confidence: 61%

“…It is assumed that there is spatial complementarity of use of the resources when trees and grass are combined, as tree roots can acquire water deeper in the soil strata (Cannel et al 1996). In a study of vertical root distribution of multipurpose tree species, Jonsson et al (1988) clarified the definition of "trees with deeper roots", because it is not clear if it infers that trees have most of their root biomass deep in the soil, or whether some roots reach deeper levels while the bulk of roots remain near to the surface. Clearly, in the Nelder fan experiment, leucaena had deeper root abundance than Rhodes grass suggesting a complementary use of water resources; however, the great abundance of fine roots of leucaena and Rhodes grass in the upper soil levels suggested a high level of competition for water resources.…”

Section: Complementarity and Competition For Water Resourcesmentioning

confidence: 99%

“…Most below-ground studies have focused on soil fertility changes, allelopathy and water uptake (Jonsson et al 1988;Rao et al 1993);van Noordwijk et al 2004). These studies have revealed that roots of both trees and crops were concentrated in the topsoil and fine root biomass decreased with soil depth, although tap and lateral roots exploited greater depths of the soil profile (Jonsson et al 1988;Dhyani et al 1990). Maximum reported root depth in leucaena-grass pastures have varied from 2.6 m in 38-year-old leucaena growing in soil with a physical root barrier, to 6 m under 5-10 year-old leucaena-pastures grown in a deeper soil (Poole, 2001).…”

Section: Introductionmentioning

confidence: 99%

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A study of water use in leucaena-grass systems

Pachas¹

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Leucaena [Leucaena leucocephala Lam. de Wit ssp. glabrata (Rose) Zarate] mixed with Rhodes grass (Chloris gayana Kunth), is widely grown in tropical northern Australia in a hedgerow silvopastoral system which is productive, profitable and sustainable for beef cattle production. However, there is poor understanding concerning the most appropriate tree densities and planting configurations for leucaena and grass forage systems. Limited studies have focused on above-ground interactions between the species with even fewer on below-ground competition. Therefore, the main objective of this thesis was to investigate above-and below-ground competition, with emphasis on water use of both the leucaena and grass at a range of leucaena densities. Additional objectives were to determine (a) the effect of plant density on above-ground interactions between the species; (b) spatial and temporal water use of both species; (c) rooting patterns and deep drainage in a commercial leucaena-grass pasture; and (d) the effect of defoliation on water use of leucaena.The following experiments were conducted to address these objectives, firstly a field monitoring experiment in a commercial leucaena-grass pasture system at north-east of Injune, Central Queensland; secondly, two experiments in a controlled glasshouse environment at the University of Queensland, St. Lucia Campus Brisbane; and thirdly, three field experiments at the University of Queensland, Gatton Campus, Gatton Australia.The detailed monitoring analysis, using high-technology soil water moisture sensors, provided water use information and highlighted that there was minimal spatial and temporal complementarity of water use between the species. This was contrary to the general agroforestry hypothesis that trees acquired water from different soil strata when grown in association with grass. A high level of competition for water was evident as most of the water extraction occurred in the top 1.5 m of the soil profile. In the second year, root activity and water extraction became shallower probably associated with overgrazing and severe pruning. Another important outcome of this experiment was the low level of deep drainage to 4 m.The effect of leucaena plant density on above and below-ground interactions was then investigated using a Nelder fan design established at Gatton research farm from

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“…Tree root distribution can be used as an indicator of competition potential of trees, and high fine root concentrations of trees within crop root zone has been observed in previous studies involving fast growing trees (Jonsson et al 1988;Daniel et al 1991;Van Noordwijk et al 2015). Previous studies have shown that the concentration of fine tree roots decreases with distance from trees (Eastham and Rose 1990;Van Noordwikk et al 2015;Livesley et al 2000).…”

Section: Discussionmentioning

confidence: 95%

Optimizing resource distribution and crop productivity in hedgerow intercropping by manipulating tree arrangement

2016

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The potential of tree arrangement in optimizing radiation and soil water distribution and crop yield of hedgerow intercropping systems was investigated using a Jatropha curcas-Pennisetum clandestinum (kikuyu) system (Ukulinga, South Africa). Treatments (1110 t ha −1 ) of Jatropha-only (JO), single-row Jatropha and kikuyu (SR), and double-row Jatropha and kikuyu (DR) were used. Treatments had asymmetrical radiation distribution across tree-crop (T-C) interfaces and different radiation interception by trees (JO: 27 %, SR: 11 %, DR: 8 %). Soil water varied among treatments and was asymmetrically distributed showing no consistent trend towards trees. Evapotranspiration was higher (p < 0.05) in SR than DR (13-65 %) and JO (16-37 %) for most part of the season. Estimated fine tree roots distribution was symmetrical in DR but not JO and SR. Total roots in SR were concentrated in the top 0.2 m (91 %) and beneath tree row (30 %), and varied inconsistently with distance from trees. Grass yields increased farther from tree rows and were higher in SR (8. ) also increased with distance from trees but irradiance correlated with grass yields poorly (R 2 < 0.32) despite high rainfall and no nutrient limitation. Considering total productivity and evapotranspiration, DR was better tree arrangement than SR. Water availability dictated T-C interactions and intercrop yield more than radiation. It was possible to optimize radiation and water distribution and intercrop growth by manipulating tree arrangement without changing density. KeywordsEfficient agroforestry design Growth Radiation use efficiency Silvopasture Tree-crop interactions INTRODUCTIONProduction of food crops and pastures in South Africa faces deterioration and limited arability of land and relatively low and erratic rainfall. Moreover, yields and food security are compromised by low agricultural production technologies practices and low inputs in resource-poor communities. One of such regions is the Coast Hinterland Thornveld region, which is classified as Bioresource Group 17 (Camp, 1997). This warm temperate region with annual rainfall (according to the Köppen classification) has an area of 113 367 ha and is characterized by severely degraded natural resources due to continuous burning to enhance fresh growth and selective overgrazing, poor water supply, frequent droughts and only 33% arable land. Vegetation in the area is wooded grasslands, woodlands and bushed grasslands dominated by secondary Acacia species and Aristida junciformis grass, which is an inedible by livestock (Everson et al. 2012). The potential exists for agroforestry to 1 be implemented a resource-efficient production system to rehabilitate the land, produce fodder to reduce pressure on the natural grasslands, and generate additional income by employing species that are tolerant to poor soils and not excessive water users.To ascertain sustainability of agroforestry systems, understanding factors and interactions involved is essential (Berlyn and Cho 2000;Ong et al 2000). Tree-crop (T-C) inte...

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The vertical distribution of fine roots of five tree species and maize in Morogoro, Tanzania

Cited by 95 publications

References 8 publications

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A study of water use in leucaena-grass systems

Optimizing resource distribution and crop productivity in hedgerow intercropping by manipulating tree arrangement

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