Measurement of Soil‐grown Roots in a Rhizotron<sup>1</sup>

Taylor, H. M.; Huck, M. G.; Klepper, Betty; Lund, Z. F.

doi:10.2134/agronj1970.00021962006200060039x

Cited by 75 publications

(47 citation statements)

References 4 publications

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“…Under moist conditions it is not the average concentration of inorganic N in the soil solution which is likely to limit uptake, but the proportion of roots which have access to it (Burns, 1980). Tomato plants utilize only a small fraction of the available soil inorganic N because of their low rooting density (Jackson and Bloom, 1990;Taylor et al, 1970). Determinant cultivars of processing tomatoes develop smaller root systems under field conditions than semideterminant fresh market tomatoes (Widders and Lorenz, 1979).…”

Section: Discussionmentioning

confidence: 99%

The effect of nitrogen source and crop rotation on the growth and yield of processing tomatoes

Cavero

Plant

Shennan

et al. 1996

Nutr Cycl Agroecosyst

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Four crop rotation and management systems were studied in 1994 and 1995 in relation to growth and yield of irrigated processing tomatoes (Lycopersicon esculentum Mill.). The four treatments were three four-year rotation systems [conventional (conv-4), low input and organic] and a two-year rotation system [conventional (conv-2)]. The four-year rotation was tomato-safflower-corn-wheat(or oats+vetch)/beans, and the two-year rotation was tomatowheat. Purple vetch (Vicia sativa L.) was grown as a green manure cover crop preceeding tomatoes in the low input and organic systems. Nitrogen was supplied as fertilizer in the conventional systems, as vetch green manure plus fertilizer in the low input system and as vetch green manure plus turkey manure in the organic system. Tomato cv. Brigade was direct-seeded in the conventional systems and transplanted to the field in the low input and organic systems. In both years the winter cover crop was composed of a mixture of vetch and volunteer oats with N contents of 2.2% in 1994 and 2.7% (low input) or 1.8% (organic) in 1995. In 1994 yields were higher in conventionally grown tomatoes because a virus in the nursery infected the transplants used in the low input and organic systems. In t995 tomatoes grown with the low input and conv-4 systems had similar yields, which were higher than those of tomatoes grown with the conv-2 and organic systems. N uptake by the crop was greater than 200 kg N ha-1 for high yield (> 75 t ha -1) and uptake rates of 3 to 6 kg N ha -I day -l during the period of maximum uptake were observed. The lower yield with the organic system in 1995 was caused by a N deficiency. The main effect of the N deficiency was a reduced leaf area index and not a reduction of net assimilation rate (NAR) or radiation use efficiency (RLrE). Nitrogen deficiency was related to low concentration of inorganic N in the soil and slow release of N from the cover crop + manure. A high proportion of N from the green manure but only a low proportion of N from the manure was mineralized during the crop season. In the conventional systems, the estimated mineralized N from the soil organic matter during the crop season was around 85 kg ha-I. A hyperbolic relationship between N content and total dry weight of aboveground biomass was observed in processing tomatoes with adequate N nutrition. Lower yields with the cony-2 than with the conv-4 system were due to higher incidence of diseases in the two year rotation which reduced the NAR and the RUE. Residual N in the soil in Oct. (two months after the incorporation of crop residues) ranged between 90 and 170 kg N ha-z in the 0-90 cm profile.

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Section: Discussionmentioning

confidence: 99%

The effect of nitrogen source and crop rotation on the growth and yield of processing tomatoes

Cavero

Plant

Shennan

et al. 1996

Nutr Cycl Agroecosyst

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“…Root-length density was calculated by dividing the length of fine roots observed in each video frame by the soil volume observed (182 mm# frame areaia depth of field of 2.5 mm) and converting to mm −$ . The 2.5-mm depth of field, midway between previously used values of 2 mm (Taylor et al, 1970) and3 mm (Itoh, 1985), was chosen because it resulted in average minirhizotron root-biomass densities which matched those determined by root coring. To determine rootbiomass density (g m −$ ), root-length density was divided by specific root lengths of 11.72 m g −" for 0-1-mm fine roots and 2.31 m g −" for 1-2-mm fine roots, which were empirically determined from root cores next to the minirhizotron tubes.…”

Section:  mentioning

confidence: 99%

Elevated CO₂ and conifer roots: effects on growth, life span and turnover

2000

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 Elevated CO# increases root growth and fine (diam. 2 mm) root growth across a range of species and experimental conditions. However, there is no clear evidence that elevated CO # changes the proportion of C allocated to root biomass, measured as either the root : shoot ratio or the fine root : needle ratio. Elevated CO # tends to increase mycorrhizal infection, colonization and the amount of extramatrical hyphae, supporting their key role in aiding the plant to more intensively exploit soil resources, providing a route for increased C sequestration. Only two studies have determined the effects of elevated CO # on conifer fine-root life span, and there is no clear trend. Elevated CO # increases the absolute fine-root turnover rates ; however, the standing crop root biomass is also greater, and the effect of elevated CO # on relative turnover rates (turnover : biomass) ranges from an increase to a decrease. At the ecosystem level these changes could lead to increased C storage in roots. Increased fine-root production coupled with increased absolute turnover rates could also lead to increases in soil organic C as greater amounts of fine roots die and decompose. Although CO # can stimulate fine-root growth, it is not known if this stimulation persists over time. Modeling studies suggest that a doubling of the atmospheric CO # concentration initially increases biomass, but this stimulation declines with the response to elevated CO # because increases in assimilation are not matched by increases in nutrient supply.

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“…Similar assumptions were made also and may not be valid either. It was assumed that the visible distance, was' 3 mm in this case, that is I.S times the value postulated by TAYLOR et al (1970). As the root concentration can be 3 times higher in the 2 mm soil layer immediately behind the mini-rhizotron window (BOHM, 1979), BOHM et al (1977) concluded that the mini-rhizotron should not be used for rooting density studies.…”

mentioning

confidence: 95%

“…TAYLOR et al (1970) measured the root length on the window and attempted to calculate the rooting density in bulk soil assuming that all roots within 2 mm of the observation panel were visible. It was also assumed that the rooting density in the soil near the observation panel was not high compared with that of the bulk soil.…”

mentioning

confidence: 99%

In situMeasurement of Rooting Density by Micro-Rhizotron

Itoh

1985

Soil Science and Plant Nutrition

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Measurement of Soil‐grown Roots in a Rhizotron¹

Cited by 75 publications

References 4 publications

The effect of nitrogen source and crop rotation on the growth and yield of processing tomatoes

The effect of nitrogen source and crop rotation on the growth and yield of processing tomatoes

Elevated CO₂ and conifer roots: effects on growth, life span and turnover

In situMeasurement of Rooting Density by Micro-Rhizotron

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Measurement of Soil‐grown Roots in a Rhizotron1

Cited by 75 publications

References 4 publications

The effect of nitrogen source and crop rotation on the growth and yield of processing tomatoes

The effect of nitrogen source and crop rotation on the growth and yield of processing tomatoes

Elevated CO2 and conifer roots: effects on growth, life span and turnover

In situMeasurement of Rooting Density by Micro-Rhizotron

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Product

Resources

About

Measurement of Soil‐grown Roots in a Rhizotron¹

Elevated CO₂ and conifer roots: effects on growth, life span and turnover