Plant Root Distribution Research Articles

Spatial and Temporal Fine‐Root Distribution in Three Louisiana Forest Soils

AbstractThe distribution of fine plant roots (≤3‐mm diam.) in three northern Louisiana forest soils was investigated. Two upland mixed pine‐hardwood sites and one bottomland hardwood site were sampled periodically for a year. Fine‐root biomass and surface area were determined on root samples extracted using wet sieving of soil corings. Both fine‐root biomass and surface area decreased abruptly with increasing depth on all sites, with 60 to 64% of the biomass and 63 to 70% of the fine‐root surface area occurring in the top 20 cm of soil. Prolonged soil wetness or dryness during the growing season caused reductions in fine‐root‐biomass concentrations. A contradictory increase in fine‐root surface area occurred, however, during prolonged soil saturation in the bottomland site, suggesting a possible change in fine‐root morphology during inundation. Total fine‐root biomass was similar on the three sites, averaging 8.4 and 10.5 Mg ha−1 on the two upland sites, and 9.9 Mg ha−1 on the bottomland site. Total fine‐root surface area was much higher on the bottomland site, however, averaging 1.48 × 105 m2 ha−1 vs. 9.5 × 104 and 7.0 × 104 m2 ha−1 on the upland sites. These data indicate that fine‐root concentrations in these forest soils decrease rapidly in response to unfavorable soil environmental conditions such as prolonged saturation or drying. These data also indicate that maximum root concentrations generally occur in the spring and early summer, with minimums during late summer, fall, and winter.

FLOODING AND DRIP IRRIGATION FREQUENCY EFFECTS ON TOMATOES IN SOUTH FLORIDA

ABSTRACT Flooding from large rainfall events is a major risk to fresh market tomato production in south Florida. Field experiments were conducted during two crop seasons to investigate the effects of flooding and irrigation frequency on plastic-mulched and staked drip irrigated tomatoes (Lycopersicum esculentum Mill.) grown on sandy soil. The (2x2) factorial experiment had two irrigation treatments, 1) more frequency (three times per day), and 2) less frequency (one time per day). Each irrigation treatment was subjected to flood and non-flood conditions. The water table was maintained at a depth greater than 0.9 m from the soil bed surface except during a five- and eight-day flooding period when the water table was raised to within 0.2 m of the top of the plant bed. During the flooding period, canopy temperatures were monitored, and soil oxygen diffusion rates were measured. Plant dry matter and root distribution were measured prior to and after flooding. Through each crop season, plant heights were measured, and final yield and grade of fruit were compared. Flooding and drip irrigation frequency treatments did not affect total yields for tomatoes grown on a sandy soil. Drip irrigation with fertigation may reduce the risk of crop damage due to a high water table following heavy rain.

A review: Radiotracer methods to determine root distribution

This paper reviews radiotracer techniques that have been used to determine plant root distribution. General methods of radionuclide solution preparation, injection, sampling, and sample counting are described. The techniques provide qualitative information on whether living, functional roots of a specific plant are present at a particular location around the plant, but not on root density or biomass. The soil injection technique has been used to determine the volume of functional roots or the maximum lateral spread at various depths, including maximum depth. The plant stem injection technique has been used, with less success, to determine the distribution of living roots, including those that are dormant.

Long-term effects of irrigation and date-palm production on Torripsamments, Saudi Arabia

Specimens of soil profiles from four date-palm orchards under irrigation for periods ranging from 10 to 230 years, were compared with one another and with a profile from the nearly barren desert. Soil properties were recorded through field and laboratory observations. Distribution and mass of plant roots in each layer to a depth of 135 cm were also measured, as was the quality of the irrigation water used in each orchard. The data indicate changes in several characteristics of the soils after they were put under irrigation. Some differences were also observed among the profiles in the orchards in relation to their ages. Differences were found in the amounts and distribution of calcium carbonate, the levels of organic matter, the values of strength and bulk density, and possibly in the amounts and distribution of the clay fraction. Total amounts of carbonates are several times larger in profiles from the older orchards than in the one from the desert. Most of that difference is in carbonates of claysize. The largest amounts of carbonates occur in the same layers as where the greatest mass of plant roots is found. Levels of organic matter are two to three times as high in the profiles in the orchards as in that in the desert, with the biggest difference between the barren profile and that in the orchard of 10 years old. Amounts of the clay fraction are greater in the profiles under irrigation, with a tendency for the amounts to increase with time. Greater amounts of clay are attributed chiefly to precipitation of carbonates in that fraction. The profiles in the orchards developed increasing strengths and decreasing bulk densities over time. Differences among the profiles thus indicate not only that pathways of genesis have been altered under irrigation but that some effects become evident in a short space of time and are gradually enhanced over longer periods.

Uptake of potassium and nitrogen by pasture from urine-affected soil

Abstract A field experiment was carried out to determine the depth of soil from which pasture plants growing in urine-affected soil recover urine potassium (K) and nitrogen (N). A comparison of the amounts of K and N taken up by the herbage with the decline in soil K and N levels showed that K and N were absorbed mainly from the 0–12 cm depth of soil. This coincides with the distribution of plant roots within the soil profile, as 86% of the roots in the 0–30 cm depth of soil were found in the top 15 cm. The experiment also showed that immediately after a dairy cow urination event in mid winter (July), up to 59% of the urine K moved preferentially through a network of soil macropores to below a soil depth of 14.5 cm. A simulation of the field trial in the glasshouse confirmed that preferential flow of the urine could result in large losses of urine K. Fortyeight percent of the urine-N was also unaccounted for by soil analysis immediately after the urination event, and is considered to have been lost prefer...

Mobility and Uptake by Plants of Elements Placed Near a Shallow Water Table Interface

AbstractThe water table interface is the transition between unsaturated, usually aerated, soil and water‐saturated, often anaerobic soil. Plant roots may approach this transition zone and absorb elements soluble in and below the transition zone. To examine this possibility, we studied elements that differ in solubility as a function of oxidation‐reduction potential. Barley (Hordeum vulgare cv. Conquest) was grown in field lysimeters, and treatments included various elements (iron, technetium and uranium plus phosphorus), element placement depths, and water table regimes. Measurements included plant uptake of each element, plant root distribution, and soil profiles of total and extractable amounts of each study element and related elements. The transition from aerobic to anaerobic conditions occurred −10 cm above the water table interface. The mobility of the elements decreased in the order Tc > U > P ≥ Fe. The redox gradient markedly modified the mobility of Tc and U. The Fe was more soluble in the reducing environment than in the oxidizing environment, but no migration of Fe was detected. The plant roots were almost entirely confined to the oxidized layers of soil. The plants absorbed no treatment Fe, very little treatment P and U (from the shallow placement only), but substantial amounts of Tc. A fluctuating water table further restricted plant uptake. The water table interface markedly changed the mobility of some of the study elements but the effect on rooting depth was more profound. Thus, the water table interface did not present a unique condition for plant roots to absorb elements as the elements diffused upward from the reducing environment.

The water balance of post-monsoonal dryland crops

SUMMARYSix dryland crops (mungbean, cow pea, soya bean, groundnut, maize and sorghum) and two rice cultivars (C·171·136 and IR 36) were grown under rainfed and irrigated conditions on a dryland site with a clay loam soil at the International Rice Research Institute, Philippines. After the first 30 days of growth there was no effective rain, and the rainfed crops encountered different water deficits. Crop productivity, leaf area, plant water status, root distribution, and soil water use were measured.Neither rice cultivar yielded seed under rainfed conditions, but all other crops did. With mungbean and cow pea there was little difference between the yields under rainfed and irrigated conditions, but groundnut, soya bean, sorghum and maize gave higher yields under irrigation.The rainfed crops extracted different amounts of stored soil water, ranging from 100 mm for IR 36 to 250 mm for groundnut. The different amounts were associated with different growth durations, rooting depths and rates of soil water depletion from within the root zone. Biological productivity of the six rainfed crops with the C 3 photosynthetic pathway was linearly related to transpiration, which was estimated from soil water extraction and soil evaporation. Biological productivity per unit of transpiration for the two crops with the C 4 pathway was 2·2 times higher than for those with the C 3 pathway. The different seed yields of the rainfed crops were due to differences in harvest index and the chemical composition of seeds, as well as to biological productivity.The results are discussed in relation to the potential for growing dryland crops after rice in rice-based cropping systems.

Traffic-soil-plant (maize) relations

Twenty-five treatments consisting of three vehicle contact pressures, 62, 41 and 31 kPa (0.63, 0.42, 0.32 kg/cm 2), four numbers of tractor passes (1, 5, 10, 15,) before and after seeding groups, and a control of zero traffic were used to study the effect of soil compaction on corn plant root growth and distribution in a Ste. Rodalie clay soil. The average dry bulk density values for 0–20 cm depths measured during the season varied from a minimum of 0.89 g/cm 3 to a maximum of 1.12 g/cm 3 depending on the severity of the treatment. Root distribution maps were obtained for all the treatments by field measurements coupled with root washing methods. An average root density of 5.7 mg/g of soil in an uncompacted control plot was reduced to less than 2 mg/g in a plot with 15 passes of 0.63 kg/cm 2 contact pressure. Soil penetration resistance values in various plots were compared, and a statistical model was obtained in terms of the traffic treatments, soil moisture content and depth. Yield reductions and penetration resistance were compared to root distrubution density results.

Plant root distribution and water use patterns of some pasture and crop species

Abstract During a summer of lower-than-average rainfall, yield, root distribution, and soil moisture tension were measured for perennial ryegrass, white clover, ryegrass-clover mixture, cocksfoot, wheat, maize, and lucerne growng on a deep free-draining soil. In all species most roots occurred in the top 20 cm of soil, root numbers decreasing down to 100 cm, with smaller variable numbers at the maximum depth sampled. Cocksfoot and perennial ryegrass had the highest root numbers in the top 40 cm, cocksfoot roots continuing to be more numerous to 140 cm. The effective depth of the soil exploited for water by all species except lucerne was approximately 130 cm. Lucerne extracted water from at least 210 cm. Lucerne, maize, and cocksfoot produced at least twice as much dry matter as ryegrass and white clover, both of which had stopped growing by the final harvest. Maize which was not sown until late spring did not begin to deplete the soil water until the pasture species had used much of that which was available. Lucerne depleted the soil water uniformly at all levels of the profile to 150 cm, whereas all other plots showed depletion first near the surface and only later at greater depths This could be significant in maintaining nutrient availability under drying conditions.

Water Movement in Bare and Cropped Soil Under Isolated Trickle Emitters: II. Analysis of Cropped Soil Experiments

AbstractSoil moisture and plant root distributions were evaluated when plots of summer squash (Cucurbita pepo var. Zucchini) were trickle irrigated with two contrasting frequencies of water application. Replicated plots receiving the same total volumes of water were irrigated three times daily and once weekly, with irrigation volumes adjusted according to evapotranspiration and tensiometric data. In the presence of actively growing zucchini, weekly irrigations produced a greater movement of water both laterally and vertically downward than daily irrigations. Plant roots were distributed according to the wetted volume of soil, with roots of weekly irrigated plots being more evenly distributed than in daily irrigated plots where roots were concentrated beneath the emitter. The imposition of a water stress demonstrated a marked increase in root density beneath the emitters as a result of proliferation of fine root material.Zucchini yields in the outer ring of weekly irrigated plants (100 cm from emitter radially) were 30% higher than the most productive daily irrigated plot. Furthermore, total green matter and dry matter yields were greater in weekly irrigated plots.

Sistema radicular do morangueiro (Fragaria híbridos), em duas fases do ciclo vegetativo

São apresentados os resultados do estudo do desenvolvimento do sistema radicular do morangueiro (Fragaria híbridos), variedade Campinas IAC-2712, com 105 e 201 dias de plantio das mudas, em Latossolo Vermelho Amarelo série Barão, do município de Campinas. O morangueiro apresentou, a 5 cm de profundidade do solo, 73% e 90% em peso de suas raízes, respectivamente nas idades de 105 e 201 dias. A profundidade máxima atingida pelas raízes nas duas idades estudadas foi de 55 cm.

Plant Growth and Root Distribution in Layered Sand Columns1

AbstractGrowth of tomato plants in relation to moisture retention in uniform and layered sand columns was investigated in growth chamber environment. Fourteen acrylic plastic columns were filled with alternating coarse‐ and fine‐textured sand in seven different layering arrangements, each replicated twice. Tomato plant growth and root distribution within the layered columns were correlated with moisture retention of the respective layers. Implications of results to field irrigation management are discussed.

Estimation of the Distribution of Plant Roots in Soil

THE difficulty of measuring the distribution of living roots in soil is an obstacle to quantitative studies of the performance of root systems in natural conditions. Even the most careful procedures for separating roots from soil are subject to limitations1. Errors occur especially in estimates of the distribution of the finer lateral roots, which may be of major interest because they can account for a considerable fraction of the total nutrient uptake2. It is, moreover, often impossible to distinguish living from dead roots. An alternative approach to this problem is the injection into plant shoots of radioactive tracers which become reasonably uniformly distributed throughout the root systems. Racz et al.3 and Halstead and Rennie4 injected phosphorus-32 into plant shoots and estimated the distribution of living roots from measurements of phosphorus-32 in soil samples. The low penetrating power, however, of the beta radiation from phosphorus-32 makes it possible to assay only small soil samples, and the quantities of tracer (for example, 300 µc./plant) which are convenient for measurement4 can cause the concentration in roots to be within the range which may induce radiation injury5. A tracer which emits gamma radiation of reasonable energy would have obvious advantages and the use of rubidium-86 was therefore investigated.

Erratum

Six plant communities occurring within the ponderosa pine (Pinus ponderosa) and white fir (Abies concolor) zones were identified east of the Cascade Mountains in south—central Oregon. These units, listed in order of increasing effective moisture and increasing elevation, are as follows: (1) Pinus ponderosa/Purshia tridentata, (2) Pinus ponderosa/Purshia tridentat/Festuca idahoensis, (3) Pinus ponderosa/Purshia tridentata—Arctostaphylos parryana var. pinetorum, (4) Pinus ponderosa/Ceanothus velutinus—Purshia tridentata, (5) Pinus ponderosa/Ceanothus velutinus, and (6) Abies concolor/Ceanothus velutinus. The Pinus/Purshia/Festuca association is restricted to areas of Shanahan coarse study loam, while the remaining five units all occur on Lapine loamy coarse sand. Both series are Regosols developed on aeolian pumice deposits. Lapine profile characteristics influencing plant root distribution, such as thickness of the gravelly C1 horizon and amount of mixing of C2 material with the buried soil, showed some ap...

Soil‐Vegetation Relationships within the Ponderosa Pine Type in the Central Oregon Pumice Region

Six plant communities occurring within the ponderosa pine (Pinus ponderosa) and white fir (Abies concolor) zones were identified east of the Cascade Mountains in south—central Oregon. These units, listed in order of increasing effective moisture and increasing elevation, are as follows: (1) Pinus ponderosa/Purshia tridentata, (2) Pinus ponderosa/Purshia tridentat/Festuca idahoensis, (3) Pinus ponderosa/Purshia tridentata—Arctostaphylos parryana var. pinetorum, (4) Pinus ponderosa/Ceanothus velutinus—Purshia tridentata, (5) Pinus ponderosa/Ceanothus velutinus, and (6) Abies concolor/Ceanothus velutinus. The Pinus/Purshia/Festuca association is restricted to areas of Shanahan coarse study loam, while the remaining five units all occur on Lapine loamy coarse sand. Both series are Regosols developed on aeolian pumice deposits. Lapine profile characteristics influencing plant root distribution, such as thickness of the gravelly C1 horizon and amount of mixing of C2 material with the buried soil, showed some apparent correlations with plant communities. The Lapine soil under the Pinus/Purshia and Pinus/Ceanothus—Purshia communities had thickest C1 horizons and the smallest amounts of mixing in the C2. The soil associated with the Pinus/Ceanothus community had the thinnest C1 and a well—mixed C2 horizon. Roots were generally well distributed throughout the C2 horizon in the latter community, whereas in soils possessing a thick C1 and little mixing in the C2 roots are restricted largely to the A1, AC, and D horizons. Soil—moisture measurements indicated that depth and time of onset of soil drought are important factors in controlling the distribution of plant communities in the study area. The A1 horizon under Pinus/Ceanothus and Abies/Ceanothus communities contained appreciably greater quantities of available P, exchangeable Ca, and total N. Organic matter content of the Lapine A1 horizon was considerably higher under the more mesic communities. Carbon—nitrogen ratios of Lapine and Shanahan A1 and AC horizons were not correlated with plant groupings. C/N values were found to be very much higher than those encountered in surface horizons of zonal forested soils, probably due to slow rates of organic matter decomposition.

Studies on Root-Breaking in Certain Crop Plants Caused by the Formation of IcicIe-Layer in the Ground and on Protection Methods against Them : 3. Formation of Ground-Cavity and Its Relation to the Plant Roots

When we observe the profile of frozen soil, we find frequently a cavity formed underneath the root system of a plant. Its profile shows a lenticular shape generally, but sometimes it shows a different one. Under the ridge of rye, cavities are often connected each other and make a long hole like a tunnel along the ridge. Cavities can be found under any kind of crops-rye, wheat, barley, rape, hairy vetch, red clover and orchardgrass, and even under the stubble of plants-maize, millets, soybeans and weeds. The plant roots are found cut by such a cavity formed underneath them. The condition of the cavity varies with the development of the root system. The more vigorous the growth the deeper is the place of its formation under the same kind of plant. When the plant has very poorly developed root system, its roots are cut directly by the icicle layer without forming cavities. Therefore, the formation of cavity is much related to the field practice of crop cultivation. On the inner surface of cavity there are ice crystals, which may be considered as sublimates of vapor from unbrozen part of the soil. The mechanism of cavity formation will be explalined as follows. In the process of icicle-layer formation, it develops spreading horizontally beneath the frozen layer in the soil; but at the parts straightly below the plants, the icicle formation is avoided by the dense distribution of plant roots. With the thickening development of the icicle-layer the frozen surface soil layer is heaved as a whole, and the plant bodies grasp in the latter with their roots are pushed upwards, remaining cavities beneath it, and thus the roots distributed there are stretched and broken finallly (Fig. 2).

Tomato root distribution under furrow irrigation

The root distribution of mature tomato plants in a sandy loam soil under furrow irrigation was studied by measuring the lengths of roots washed from soil samples. Nearly 76 per cent. of the roots measured were found in the top 40 cm. of soil, but appreciable amounts of roots were found in the deepest samples (90-100 cm.). There were more roots half-way between plants in the row than closer to the plant, which suggests that mature root systems overlap when plants are spaced 29 ft. apart in the row. Distribution was compared for plants which had received an application of superphosphate and those which had not. Added phosphorus greatly increased the total length of roots and slightly increased the median root depth without much change in the relative values for these two measures between different lateral positions. In addition, there was some evidence for a local concentration of roots around the band of superphosphate. The relevance of the findings to cultivation and fertilizer practices in tomato culture is briefly discussed.

Plant Root Development and Distribution by Soil Type

Agronomy JournalVolume 24, Issue 1 p. 82-82 Note Plant Root Development and Distribution by Soil Type H. H. Bennett, H. H. Bennett U. S. Dept. of Agriculture, Washington, D. C.Search for more papers by this author H. H. Bennett, H. H. Bennett U. S. Dept. of Agriculture, Washington, D. C.Search for more papers by this author First published: 01 January 1932 https://doi.org/10.2134/agronj1932.00021962002400010008xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume24, Issue1January 1932Pages 82-82 RelatedInformation