Review of Quantitative Root Length Data in Agriculture

Noordwijk, Meine van; Brouwer, G.

doi:10.1016/b978-0-444-89104-4.50071-2

Cited by 50 publications

(31 citation statements)

References 37 publications

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“…2d). The mean SRL of 98 m g ±1 for the total root system was in the typical range for field-grown dicotyledonous plants, while the values for f-roots were close to those reported for fibrous roots of grasses (Van Noordwijk and Brouwer, 1991). Roots with high SRL maximize their surface area and, thus, the volume of soil that can be explored by a given investment in root biomass.…”

Section: Resultsmentioning

confidence: 53%

Root morphology of Thlaspi goesingense Hálácsy grown on a serpentine soil

Himmelbauer¹,

Puschenreiter

Schnepf

et al. 2005

Z. Pflanzenernähr. Bodenk.

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The contribution of root morphology to enhanced uptake of heavy metals by hyperaccumulating plants is not well understood. The objective of this study was to describe root-morphological characteristics of the natural nickel (Ni) hyperaccumulator Thlaspi goesingense Hµlµcsy. Plant samples were collected from a serpentine site near Redlschlag (East Austria), characterized by large soil Ni concentrations. Roots were evaluated for mass, length, surface area, diameter, and related ratios using an image-analysis approach. Results showed that on the indigenous site, T. goesingense Hµlµcsy developed a fine-branched root system, confined within a shallow soil depth. Coarse roots (>1 mm) accounted for about 60% of the total root mass (fresh and dry), while their contribution to the surface area and especially to the length of the system was small. Conversely, fine roots (<1 mm) represented 99% of the total root length and 88% of the surface area. The largest proportion of root length and area was found in the smallest diameter class of 0.0 to 0.5 mm. Shootbiomass production per unit root was high, in spite of the adverse soil conditions. Roots accounted for 8% of the total plant mass and about 4% of the total Ni accumulation. We conclude that the root system of natively grown T. goesingense Hµlµcsy exhibits a potential for enhanced Ni extraction from soil, since it mainly consists of very fine roots with extended absorptive area.

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Section: Resultsmentioning

confidence: 53%

Root morphology of Thlaspi goesingense Hálácsy grown on a serpentine soil

Himmelbauer¹,

Puschenreiter

Schnepf

et al. 2005

Z. Pflanzenernähr. Bodenk.

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“…Moreover, roots with a smaller diameter will have a better nutrient uptake as demonstrated by Itoh and Barber (1983a) Richards and Greacen (1986), fine roots are also less affected by high mechanical impedance, even though in very compacted homogeneous soil (penetrometer resistance 4.2 MPa) there is a positive correlation between root diameter and elongation (Materechera et al 1991). Noordwijk et al (1993) found, however, no relation between root-soil contact and root diameter or roundness.…”

Section: Efficiency Of Root Systemmentioning

confidence: 67%

“…To a depth of 30 cm the root length density of carrot fibrous roots (0.5-1 cm cm 3 per plant) was in the range of other dicotyledonous species (Noordwijk and Brouwer 1991) (Xu and Juma 1994), the carrot fibrous root length followed a similar trend as root dry weight. In loose fine sand at the depth of 15-25 cm, however, the root dry weights were relatively slightly lower than the root length.…”

mentioning

confidence: 66%

Effect of soil compactness on the growth and quality of carrot

Pietola¹

1995

AFSci

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Field experiments were performed in Southern Finland on three soil types: fine sand (1989-1991), clay (1989) and mull (1990-1991). The following soil mechanical treatments were applied to autumn ploughed land: soil loosening by ridge preparation (ridge distance 45 cm), rotary harrowing (to a depth of 20 cm, clay 15 cm), and soil compaction track by track by a tractor weighing 3 Mg (1 or 3 passes, wheel width 33 cm) before seed bed preparation. One plot was untreated. These treatments were set up in April (on clay in May) under moist soil conditions. Sprinkler irrigation (one application of 30 mm) was applied to clay and fine sand when soil moisture in top soil had decreased to around 50% of plant-available water capacity. PVC cylinders (r = 15 cm, h = 60 cm) were fixed in the experimental areas during the growing periods. At harvest, these cylinders were removed for specific analysis of tap and fibrous roots of carrot. Length and width of fibrous roots were quantified by image analysis in the USA. The impacts of soil loosening and partial compaction were determined by measuring soil physical parameters to a depth of 25 cm in mineral soils, and to greater depths in organic soil. Dry bulk densities of the plough layers increased with increasing tractor passes by 8%, 10% and 13% for fine sand, mull and clay soils, respectively. The lowest dry soil bulk density in the plough layer was obtained by rotary harrowing to a depth of 20 cm. Comparison of gamma ray transmission and gravimetric analysis indicated that dry soil bulk density was slightly lower when determined by gravimetric analysis. Increased soil bulk densities were reflected by increased water retention capacity (matric suction ≤ 10 kPa) and greater penetrometer resistance. Relatively similar increases in bulk density increased the penetrometer resistance much less in mull than in fine sand. In contrast, greater bulk densities in the mull soil affected soil air composition adversely by decreasing the O2 content to 10% when the subsoil had high wetness. In other soils, the lowest soil oxygen contents of 16-18% were recorded in early summer (compacted clay) and during periods of vigorous plant growth (fine sand) when soil water contents were high. Even though the highest degree of soil compactness (D) in a plough layer approached 93 (gravimetric) in all soils, only clay soil was compacted to a soil macro-porosity below 10% (pore diameter > 30 μm). Soil compaction promoted crop establishment and early growth as compared with loose soil beds. Optimum soil compactness for carrot yield (D = 82) was observed only in clay field where excess loosening or compaction affected yield quantity adversely at different stages of growth. During biomass accumulation, excessive penetrometer resistances limited tap root growth in compacted fine sand without irrigation. Water applications promoted shoot growth, but did not affect final shoot and tap root yield. Among the three soil types tested in this study, compaction of mull soil had the least effect on carrot growth and external quality. This paper presents evidence that the internal quality of carrots is only slightly affected by changes in soil physical properties, while the adverse effects of soil compaction on carrot external quality (short, deformed and conical tap roots with greater maximum diameters) are clear. Even though compacted clay soil greatly limited the biomass accumulations in the tap root, which had a high crude fibre content, the carotene (10 mg/100 g carrots) and sugar contents (5%) reached acceptable levels. The lowest carotene contents (4 mg/100 g carrots) were observed in loose mull, following a cool late summer in 1990. The effect of irrigation on carotene content varied from one year to another. High sugar and carotene contents appeared to respond to the high below-ground absorption surface. The fibrous root system of carrots, consisting of mostly very fine roots (diameter 0.15 mm), had total lengths of 150 m in loose fine sand at a soil depth of 0-50 cm (rotary harrowed), 200 m and 300 m in fine sand and mull soils subjected to 3 passes by a tractor wheel. The maximum dry weight (60 μg), length (1.2 cm) and surface area (0.05 cm2) of the fibrous root system per soil volume (cm3) were observed in compacted or irrigated soil to a depth of 30 cm, and also in relation to tap root dry weight. This suggests a capacity of carrot plant for high below-ground absorption potential and optimal biochemial maturation of tap root tissue even when surface soils are compacted. This is supported by higher leaf area, as the early shoot growth was promoted by partial soil compaction. Soil compaction affected the soil physical properties and carrot external quality in agreement with previous studies. Carotene and sugar contents appeared to be unaffected or were slightly increased in riper and firmer carrots of compacted soils. This is consistent with the earlier information about the internal quality of carrot which is shown to be highly dependent on genetic factors and developmental stage of carrot. The present study emphasizes the surface area of carrot fibrous root system as a beneficial factor for maintaining high levels of carotene and sugar contents in tap roots after partial soil compaction.

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“…Root distribution of field crops (Van Noordwijk and Brouwer, 1991) as well as other plant communities have been summarized in sufficient detail to allow for some general conclusions on subsoil resource use, but this level of information is not yet available for tree-based cropping systems. In this publication tree-based cropping * FAX No: systems are defined as all land-use systems where trees play an important part in the production.…”

Section: Introductionmentioning

confidence: 99%