Cotton Root Growth Research Articles

In‐Row Subsoiling and Potassium Placement Effects on Root Growth and Potassium Content of Cotton

AbstractOne method of correcting K deficiencies in cotton (Gossypium hirsutum L.) is by in‐row deep placement of K fertilizer. At present, the mechanisms involved in cotton yield response to deep placement of K have not been elucidated. A field study was conducted in 1990 and 1991 to evaluate root development and dry matter yield of cotton as affected by in‐row subsoiling and placement of K fertilizer. The experiment was located in central Alabama on a Norfolk fine sandy loam (fine‐loamy, siliceous, thermic Typic Kandiudult). Five treatments were compared: (i) check, without in‐row subsoiling; (ii) check, with in‐row subsoiling; (iii) 84 kg K ha−1 surface‐applied, without in‐row subsoiling; (iv) 84 kg K ha−1 surface‐applied, with in‐row subsoiling; and (v) 84 kg K ha−1 deep‐placed, in‐row. Penetrometer readings taken in 1991 demonstrated that the soil has a well‐developed traffic pan at a depth of approximately 15 to 38 cm. In‐row subsoiling disrupted the pan up to 25 cm away from the in‐row position. Root density measurements taken in‐row showed that root growth at depths > 20 cm was improved by in‐row subsoiling and K fertilization. Cotton root growth at depths > 20 cm was generally better for the treatment receiving the deep applied K. However, broadcast K in combination with in‐row subsoiling resulted in the highest productivity and K accumulation per plant. Results of this study suggest that, for cotton production in Alabama, deep placement of K is not superior to broadcast applications of K.

Cotton root growth as affected by changes in soil water distribution and their impact on plant tolerance to drought

The capability of mature cotton plants (Gossypium hirsutum L.) to adjust to progressive drying of their root zone by promoting root growth to adjacent wetted zones, and the implications of this process on irrigation design were investigated. Field grown plants that developed shallow root systems in response to a drip irrigation management of daily, surface soil wettings were exposed 85 days after emergence (DAE), while in the flowering stage, to a sudden change in water distribution in the form of deep soil wetting (DSW) followed by termination of irrigation. The shallow rooted plants (SRP) failed to respond to further surface soil wetting and the progressive drying of the profile by rapid root growth to the deeper-wetted zones; consequently, the SRP suffered from water deficiency for at least two weeks, evidenced by a gradual decrease in their leaf water potential (Lψw). Potted plants responded similarly. Daily irrigations of the pot surface with water amounts similar to those lost by evapotranspiration led to the development of a system in which most of the roots and available water became concentrated at the pot's upper section. A transition to irrigation from the bottom of the pot led to a reversed soil-water content gradient and failed to promote rapid root spreading to the deeper-wetted layers, in spite of the accelerated drying of the upper zone. The slow deepening of the root system was accompanied by water-stress symptoms as indicated by a considerable reduction in dry matter production. The root shoot ratio in these plants was not much greater than in non-stressed plants in which the surface wetting was continued. This indicated that preferential root growth relative to the shoot did not occur in response to the progressive drying of the shallow root zone. Rewetting of the root zone after a long period of soil water deficiency failed to promote rapid recovery of the root system in the form of root regrowth in this zone. It was concluded that the capability of mature cotton plant roots to adjust their growth to large changes in water distribution in the soil, is slow and that this should be taken into account when determining an irrigation regime in which the depth at which water is applied is changed during the growing season.

Cotton root growth as affected by P fertilizer placement

Growth chamber studies were conducted to evaluate root growth and P uptake by cotton (Gossypium hirsutum L.) as affected by the proportion of the soil volume that is treated with fertilizer P. Cotton seedlings were grown in a Dewey silty clay loam (Typic Paleudult) and a Marvyn loamy sand (Typic Paleudult). The Dewey soil had a low-P status and the Marvyn soil had a high-P status (7 and 44 mg kg−1 Mehlich I extractable P, respectively). Phosphorus was added at a constant or base rate which was added to decreasing proportions of the soil volume (i.e. 1.0, 0.5, 0.25 and 0.125). The addition of the same amount of P to decreasing proportions of the soil volume resulted in a stimulation of root growth in the P-fertilized soil volume relative to the nonfertilized soil. The degree of stimulation was similar for the two soils which differed in P status. Phosphorus uptake reached a maximum when 0.25 and 0.50 of the soil volume was treated with P on the Marvyn and Dewey soils, respectively.

Spatial and Temporal Aspects of Growth in the Primary Root of Cotton Seedlings: Effects of NaCl and CaCl2

Seedlings of cotton (Gossypium hirsutum L. cv. Acala SJ-2) were grown in modified Hoagland nutrient solution with various combinations of NaCl and CaCl2. Marking experiments and numerical analysis were conducted to characterize the spatial and temporal patterns of cotton root growth at varied Na/Ca ratios. At 1 mol m−3 Ca, 150 mol m−3 NaCl reduced overall root elongation rate to 60% of the control, while increasing Ca to 10 mol m−3 at the same NaCl concentration restored the elongation rate to 80% of the control. Analysis of the spatial distribution of elongation revealed that the presence of 150 mol m−3 NaCl in the medium shortened the growth zone by about 2 mm from the approximate 10 mm in the control and also reduced the relative elemental elongation rate (i.e. the longitudinal strain rate, defined as the derivatives of displacement velocity of a cellular particle with respect to position on root axis). Supply of 10 mol m−3 Ca at the high salt condition restored partially the relative elemental elongation rate, but not the length of the growth zone. Compared to the control, the growth trajectories showed that at 1 mol m−3 CaCl2 it took more time for a cellular particle to move through the growth zone at 150 mol m−3 NaCl, while at 10 mol m−3 CaCl it took less time and there was no difference between the NaCl treatments

Cotton root and rhizosphere responses to free‐air CO2enrichment

Plant responses to above-ambient levels of CO{sub 2} have been summarized in several excellent reviews of recent origin, each with its own special intent. Very little is known of how root and rhizosphere processes are affected by additional CO{sub 2}. To help fill this gap in our knowledge base we have begun work in this area. Herein, we describe the early results of a first ever study of cotton growing in an open filed enriched with CO{sub 2}. Data suggest that elevated atmospheric CO{sub 2} stimulates cotton root proliferation. It may be inferred that other below ground processes impacted by root proliferation could also shift. Both root length density and root weight density appear to increase, especially in the upper layers of the soil profile. Enhanced growth of cotton roots resulted in a more thorough exploration of the soil volume occupied, possibly increasing water and nutrient availability. Increased rooting induced by CO{sub 2} enrichment could become very important for seedling establishment, especially for a crop under stress. For agronomic conditions where water and nutrients are essentially unlimited, denser root patterns may have less significance than under the limiting circumstances of more primitive or sustainable agricultural systems, or in natural ecosystems.more » A more thorough understanding of the implications of CO{sub 2}-enhanced root growth must await further experimentation. 43 refs., 2 figs., 10 tabs.« less

Temperature effects on cotton root hydraulic conductance

Soil temperatures on the Texas High Plains are below the optimum for cotton root growth and function. Cool root-zone temperatures reduce the water absorption and hydraulic conductance of roots. Our objective was to determine the response of cotton ( Gossypium hirsutum L.) root hydraulic conductance to temperature and the ability to acclimate to cool root-zone temperatures. Plants were grown in hydroponic culture in a greenhouse with root-zone temperature controlled at 30°C. Root-zone temperature was decreased to 18°C for a 14-day acclimation period at 36 days after planting. At 2-day intervals during the acclimation period the hydraulic conductance of a plant root system was measured at temperatures ranging from 30 to 7°C using a pressure chamber. Root conductance declined as temperature decreased from 30°C, declining at a slower rate at lower temperatures. Conductance at 18°C averaged 43% and at 7°C averaged only 18% of that at 30°C. Conductance of all plants responded similarly to temperature, indicating that there was no apparent acclimation of conductance to the 18°C temperature.

Soil Ca, Al, acidity and penetration resistance with subsoiling, lime and gypsum treatments

Abstract. Crop growth on strongly weathered soils is often limited by soil compaction in addition to aluminium toxicity and/or calcium deficiency. This study examines the effects of subsoiling, lime and gypsum on penetrometer resistance, acidity, aluminium and calcium levels and cotton (Gossypium hirsutum L.) root growth on soils transitional between Cecil and Appling series (clayey, kaolinitic, thermic Typic Hapludults) in the Piedmont region of Georgia, USA. The main plots were subsoiled to depths of 0.35 or 0.80 m or untreated. Dolomitic limestone (0 or 4.03 t per hectare on subplots) and phosphogypsum (0 or 10 t per hectare on sub‐subplots) were incorporated into the surface soil (0.15 m). Deep subsoiling (0.80 m depth) decreased penetrometer resistance at 0.3–0.5 m depth and increased yield in two of three years, but there was no response to shallow subsoiling (0.35 m depth). Lime increased yield when surface soil water pH prior to amendment was less than a Cate‐Nelson critical value of 4.6. Gypsum moved downward much more rapidly than lime, increasing soil solution calcium ion activity to a depth of 0.8 m within 5 months of application. There were differences in clay content between replicate plots and calcium movement was faster where the clay content was less. Yield responses to gypsum in 1986 were attributed to increased root growth below 0.2 m resulting from the increased calcium ion activity. Yield response to gypsum in limed sub‐subplots was significant only in 1986.

Changes in the physical properties of a vertisol following an irrigation of cotton as influenced by the previous crop

Structural degradation of Vertisols depresses cotton lint yield by extending the period of waterlogging following irrigation or heavy rainfall. Break crops such as wheat and safflower are often grown without irrigation to improve the macroporosity of degraded Vertisols, by encouraging deep cracking, after several years of cotton production. Investigations were made into the effects of cultivated fallow, wheat and safflower on soil structure, and the growth of a subsequent cotton crop. The tests reported in this paper, done over a 12-day period following irrigation, were: soil water content and potential, core and clod bulk density, air-filled porosity, an index of macropore continuity using Rhodamine dye, and penetration resistance. The results, when compared with established limits of aeration and penetration resistance to cotton root growth, indicate that soil physical conditions at 0.25 m should have impeded root growth regardless of water content. However, cotton roots continued to extract water in this hostile soil environment; this favourable performance was attributed to the better conditions for root growth in the interaggregate fissures than those within aggregates. Apart from water content, all indicators of soil structure were able to differentiate consistently between the three crop treatments to a depth of 0.25 m. Below 0.8m, the cropped plots, particularly safflower, had lower water contents than the fallow plots.

Cotton Root Growth and Soil Water Extraction

AbstractThe inherent productivity of many fine‐textured soils depends on timely extraction of water stored deep in the profile. Growth of crop roots and their ability to extract water are of central importance to efficient utilization of these soil resources. We observed the rate at which the soil volume was explored and water was extracted by cotton (Gossypium hirsutum L. ‘GP3774’) roots in a fine‐textured soil in a subhumid environment. Measurements of root growth and water extraction were made for 2 yr in a 2.3 m deep weighing lysimeter, 3.0 m2 in area and containing an intact core of a Frio taxadjunct silty clay loam (fine, montmorillonitic, thermic Cumulic Haplustoll). Water extraction was measured with neutron probes at 10 or 11 soil depths in the lysimeter at approximately 5‐d intervals. Root length density [Lv, cm root (cm3 soil)−1 = cm−2] was estimated at 7‐d intervals by counting roots visible against clear observation tubes installed horizontally in the lysimeter every 0.2 m between 0.5 and 2.1 m. Depth of rooting increased up to 35 mm d−1 for part of the season. Maximum Lv at 0.5 m was 1.5 and 0.8 cm−2 in 1984 and 1985, respectively; at 2.1 m comparable values were 0.24 and 0.04 cm−2. When the lysimeter surface area was divided into six 0.5‐m2 regions of soil, the coefficient of variation in Lv among the regions reached 100% both early and late in the season and both at 0.5 and 2.1 m. Crop rows did not affect the spatial distribution of Lv at depths measured. Growth of the root system required about 90 kg ha−1 d−1 for part of the season. Maximal water uptake rate per length of root was approximately 5 mm3 water (mm root)−1 d−1 and occurred at 1.7 to 1.9 m. Redistribution of dry matter invested in roots near the soil surface to deeper in the profile would probably increase total water extraction by the crop.

Cotton root growth as influenced by phosphorus nutrition and vesicular–arbuscular mycorrhizas

SUMMARYCotton, Gossypium hirsutum L., was grown in the greenhouse in sand‐nutrient culture at five phosphorus (P) concentrations, and root systems were examined after 10 and 20 days. Extension rates of primary laterals and numbers of secondary laterals increased with increasing P. Cotton was grown for 6 weeks in environment cabinets in soils of three P concentrations with and without mycorrhizas. Increased P and mycorrhizas both stimulated plant growth (f. wt shoot d. wt), but however specific root length (cm root g' root f. wt) of mycorrhizal plants was reduced.

Effects of NaCl and CaCl2 on Ion Activities in Complex Nutrient Solutions and Root Growth of Cotton

Sodium displaces Ca(2+) from membranes (GR Cramer, A Läuchli, VS Polito Plant Physiol 1985 79: 207-211) and this can be related to the (Ca(2+))/(Na(+))(2) activity ratio in the external solution (GR Cramer, A Läuchli 1986 J Exp Bot 37: 321-330). Supplemental Ca(2+) is known to mitigate the adverse effects of salinity on plant growth. In this report we investigated the effects of NaCl (0-250 millimolar) and Ca(2+) (0.4 and 10 millimolar) on the ion activities in solution and on root growth of cotton (Gossypium hirsutum L.). Ion activities were analyzed using the computer program, GEOCHEM. Most ion activities in a 0.1 modified Hoagland solution were significantly reduced by both NaCl and supplemental Ca(2+). Ion-pair formation and precipitation were significant for some ions, especially phosphate. Root growth of 6-day-old seedlings was stimulated by low NaCl concentrations (25 millimolar). At higher NaCl concentrations, root growth was inhibited; the concentration at which this occurred depended on the Ca(2+) concentration and the growth index used. Supplemental Ca(2+) mitigated the inhibition of root growth caused by NaCl. There was a curvilinear relationship between root growth and the (Ca(2+))/(Na(+))(2) ratio in the nutrient solution. The mechanisms by which Na(+) and Ca(2+) may affect root growth are discussed.

Planting pattern effects on yield, water use and root growth of cotton

Abstract Several skip-row planting systems, designed to make soil water from fallowed rows available to plants in adjacent planted rows, are used in many of the cotton growing regions of the United States and the world. Three planting designs were established in 1980 and 1981 by planting every row (solid), two of three rows (2×1), or two of four rows (2×2) to determine the effectiveness of skip-row planting systems for cotton development and yield. Soil water extraction from planted and fallow rows was determined by neutron scattering, while soil cores were used to determine root length density (RLD) in planted and fallowed beds. Cotton in the 2×2 and 2×1 patterns yielded 71 and 47% more lint than the solid design when determined on a planted area basis. No differences in yield, however, were detected on a total area basis. Cotton in the solid pattern had significantly higher micronaire, while the skip-row designs resulted in greater staple length. Seasonal water extraction was similar for the planted rows of all designs and for the fallowed row of the 2×1 pattern. Fallowed rows of the 2×2 pattern exhibited the least water removal. Water use efficiency (WUE) was not influenced by pattern in 1980, with all designs having values of about 3.0 kg lint ha−1 mm−1 water. Water use efficiency decreased to 2.1 for the solid and 2×1 patterns and to 1.6 kg ha−1 mm−1 for the 2×2 design in 1981. Cotton in the solid design generally exhibited the greatest RLD at 0–150 mm. No significant differences between treatments were observed at lower soil depths. Root length density tended to decrease between sampling dates in this study. Rooting activity was significantly correlated with water use. Based on yields, fiber characteristics, and WUE, skip-row systems were not more efficient than planting every row.

Sensitivity of agricultural ecological system models and implications for vulnerability to toxic chemicals

AbstractPublished results of sensitivity experiments on agricultural models by international authors are analyzed with a simple univariate sensitivity index. Values for system parameter and response‐effects at ratios greater than 2.0 or 3.0 are presented for different crop plants, ecosystem components and processes. Responses are ranked according to their level of sensitivity to direct and indirect changes that conceivably could be imposed by manufactured chemicals. Of several hundred agricultural modeling publications, only 8.5% was found to contain results from sensitivity analysis experiments performed by their original authors. This low proportion means that environmental interactions and biological species other than those for which such results are published might be of equal or greater sensitivity and importance if comprehensive sensitivity analyses were available across all crops and ecological processes.Results imply that hydrological flows, soil nutrient losses, and pesticide losses might all be quite vulnerable to disruption if indirect effects could be transferred through ecosystems by changes in weather and climate. Below‐ground primary production processes in agroecosystems such as cotton, semiarid range pastureland, perennial ryegrass and sugar yield of sugar beets might be vulnerable to potential, direct, sublethal effects of chemical substances. If climatic processes were changed, indirect effects could be expected in cotton and pasture root growth, and potato yields. Results also indicate that vegetative growth of corn, alfalfa, soybean and perennial ryegrass might all be extremely vulnerable to any indirect effects from chemically induced climatic changes. Reproductive parts that could be especially vulnerable to possible potential direct effects from chemical substances include seed yield of annual semiarid pastures, fruit quality of hardwood trees and, specifically, apple fruit production. If any indirect effects are possible, it appears that grain sorghum and grain corn yields, and apple fruit yields might be very vulnerable. All these results are limited to the particular designs of the models used and the response variables on which data are available from simulations.

Corn and Cotton Root Growth in Response to Soil Impedance and Water Potential

AbstractThe equation dL/dt = C · L, which relates root elongation rate (dL/dt) to root length capable of growth (L), was tested on split root systems of corn and cotton under controlled laboratory conditions. Evidence is presented for the validity of the equation for the various parts of the root system when the growth period was up to 50 days. While the equation held, C, the specific root growth rate, was affected by soil impedance and water potential (ψ), varying between 0.02 and 0.15 per day for the cotton and between 0.03 and 0.28 per day for corn. When the various parts of the root system were under the same soil density (d) and different ψ, C varied with ψ according to a bell‐shaped relationship. When d was different, C decreased monotonically with increasing d values.The flux of water uptake by cotton and corn had a peak at a matric potential between −0.13 and −0.20 bar and was about 0.02 and 0.03 ml cm−1 root day−1, respectively.

Pathogenicity and Population Increase of Paratrichodorus Minor as Influenced By Some Environmental Factors

The relative importance of the effect of soil temperature, soil texture and host species on the increase and the pathogenicity of a population of Paratrichodorus minor from Israel was studied. Populations increased fastest at 26° C, followed by 30°, 22° and 18°, approaching the host-specific equilibrium density after 90 days. In the presence of a host, populations thrived better in sand and sandy loam than in clay, but were obviously sensitive to moisture fluctuations. Host species affected population increase more than soil temperatures and soil types. In fallow, survival was better in clay and sandy loam than in sand. In vitro, P. minor fed vigorously on epidermal cells in the elongation and meristematic zone of wheat and eggplant roots, causing browning and collapse of the epidermis and cessation of growth. After detaching itself from the feeding site, the nematode left a small tube attached to the cell wall. In pathogenicity trials, two good hosts - eggplant and cotton - showed different responses: growth of eggplant was drastically inhibited at an inoculation level of 200 nematodes per plant, while populations of up to 800 nematodes per plant stimulated growth of cotton roots and tops. Infested eggplant seedlings exhibited a severely thinned and shortened lateral root system and stunted tops.

Cotton Root Growth and Uptake of Nutrients: Relation of Phosphorus Uptake to Quantity, Intensity, and Buffering Capacity

AbstractCotton (Gossypium hirsutum var. ‘Stoneville 213’) was grown in greenhouse pots containing Hartsells fine sandy loam. Four rates of P were employed and the crop was harvested on three different dates. Dry matter yield of tops and uptake of P were measured. Roots were recovered and their length determined. These data were used to calculate a rate of P uptake per meter of roots which in turn was related to quantity and intensity of soil P. A parameter that combines the effects of quantity, intensity, and P buffering capacity was derived, and rate of P uptake was found to be related to this parameter. Rate of P uptake increased with rate of root growth.

The Effect of Trifluralin on the Growth and Development of Cotton and Safflower Roots

The permanent effect of trifluralin (α,α,α-tr ifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) on the growth and development of cotton and safflower roots was studied. In cotton, increased length of trifluralin treatment resulted in a progressive loss in the ability of the treated roots to grow; after 96 hr of treatment the roots neither elongated nor formed new laterals. However, safflower roots were not permanently injured after 96 hr of treatment. On the contrary, all of the safflower primary roots observed were capable of undergoing renewed growth (after a treatment period of 96 hr). Longer periods of treatment apparently did affect the ability of safflower primary roots to grow, but their capacity to form new lateral roots was unaffected Histological observations demonstrated that in cotton, lateral root initiation is arrested before cell division is completed in the pericycle In safflower no such effect was observed, and well-developed normal primordia were observed in primary roots which had been tr...

Influence of Osmotic Potential, Temperature, and Calcium on Growth of Plant Roots1

AbstractStudies to determine influences of temperature, osmotic potential, and Ca on root growth were conducted. Hourly elongation of pea roots at 27C was a maximum of about 1.0 mm/hr after 64 to 72 hours. Osmotic potentials of −7.8 and −13.1 bars reduced root growth of peas by about 50 and 85%, respectively. Maximum hourly elongation of cotton was about 3.3 mm/hr at 32 to 38 C after 24 to 48 hours. At optimum temperature conditions and salinity levels of −0.8, −6.6, and −12.9 bars, maximum root elongation of cotton averaged 3.3, 1.8, and 0.8 mm/ hr, respectively. Optimum temperature for root elongation of cotton varied from 27 to 38 C depending upon the salinity and Ca levels. At low salinity levels Ca requirement for maximum elongation was low, but at moderate and high salinity levels Ca requirement for maximum elongation was 15 to 20 meq/liter. The stimulatory effect of Ca on root growth of cotton under salinity conditions was greatest at high temperatures (32 to 38 C). However, root growth and vigor was significantly improved by Ca at low temperatures (21 C). Calcium seems to induce root vigor and growth at adverse soil temperatures and salinity conditions. Additions of Ca may promote better stands and higher yields on certain soils.

Effect of Fungicides, Herbicides and Combinations on Root Growth of Cotton1

AbstractWe studied the effect of soil‐applied herbicides and fungicides on cotton (Gossypium hirsutum L.) root growth under ambient greenhouse conditions. Root growth of cotton was not affected by soil treatment with the fungicides 1‐Chloro‐2‐Nitropropane (Lanstan)3 or Pentachloronitrobenzen+ e 5‐Ethoxy‐3‐trichloromethyl‐l‐l‐l,2,4‐thiadiazole (Terraclor Super X)3. Trifluralin (α,α,α, trifluoro‐ 2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) applied at 0.84 kg/ha did not affect cotton roots when applied preplant and incorporated; however, the higher rate (1.68 kg/ha) significantly reduced total root growth. Fluometuron [l,l‐dimethyl‐3‐(α,α,α,‐trifluoro‐m‐tolyl)urea] was not injurious to cotton at the rate evaluated. Root growth of cotton was significantly reduced by treatment with 3.36 kg/ha of prometryne [2‐4‐bis(isopropylamino)‐6‐(methylthio)‐s‐triazine] applied as a preemergence spray. There were no significant interactions between fungicides and herbicides; however, interaction as evidenced by a reduction in total growth did occur between trifluralin and prometryne. Based on pesticides evaluated in this series of experiments, deleterious interactions as have been reported by other researchers to occur between herbicides and insecticides do not occur.

Root Growth of Cotton as Measured by P32 Uptake1

AbstractDevelopment of the root system of cotton (Gossypium hirsutum L.) under irrigated conditions was measured by uptake of P32 variously placed throughout the soil in dissolvable gelatin capsules. Corrections were made for small differences in P32 availability within the soil profile as determined from a greenhouse study. The tap root grew at an average rate of 2.5 cm per day to a depth of 183 cm, the deepest placement. Lateral roots grew at one‐half this rate. The basic framework of the root system was established by the onset of flowering approximately 10 weeks after planting as evidenced by measurable activity at all placements, although twothirds of the total activity on this date was confined to the top 30 cm. Root activity at the lower depths intensified as the season progressed. This resulted in relatively uniform activity through the first 122 cm and significant activity down to 183 cm at the end of the 130 days