The effect of soil compaction and fumigation on poor early growth of wheat under direct drilling

1989 ◽  
Vol 40 (2) ◽  
pp. 221 ◽  
Author(s):  
KY Chan ◽  
JA Mead ◽  
WP Roberts ◽  
PTW Wong
Keyword(s):  
Soil Compaction ◽  
Conventional Treatment ◽  
Shoot Growth ◽  
Dry Weight ◽  
Early Growth ◽  
Soil Fumigation ◽  
Biological Factors ◽  
The Poor ◽  
Direct Drilling ◽  
Micro Organisms

Poor early growth of wheat was studied in a tillage experiment at Cowra, N.S.W., in the 1986 season to determine the involvement of soil physical and biological factors in this problem. A compaction treatment to achieve bulk density and shear strength comparable with those detected in the direct-drilled soils was imposed on the conventionally cultivated soil. Soil fumigation was used to investigate the significance of biological factors in causing poor early growth. In the absence of fumigation, the dry weight per plant 98 days after sowing for the direct-drill treatments was approximately a third of the conventional treatment. The fumigation treatment was effective in completely eliminating the poor early growth observed in the direct-drilled soils. No significant reduction in shoot growth was detected as a consequence of the compaction treatment, despite a reduction in root growth to the level detected in the nil fallow. The results suggest that poor early growth was caused by micro-organisms present in the direct-drilled soils.

Reduced early growth of direct drilled wheat in southern New South Wales: causes and consequences

1987 ◽  
Vol 27 (6) ◽  
pp. 869 ◽  
Author(s):  
PS Cornish ◽  
JR Lymbery
Keyword(s):  
Water Use ◽  
Shoot Growth ◽  
New South ◽  
New South Wales ◽  
Dry Weight ◽  
Early Growth ◽  
Plant Population ◽  
Root Extension ◽  
South Wales ◽  
Direct Drilling

In five experiments with wheat over 4 years on a red earth soil in southern New South Wales, direct drilling reduced plant population by an average of 15% and individual plant dry weight at 10- 11 weeks by an average maximum of 33% compared with sowing into a cultivated seed bed. The maximum reduction in dry weight per unit area averaged 44% (at tillering), but compensatory growth reduced this to 17% by anthesis. Time to emergence was not reduced and differences in plant weight soon after emergence were very small, which suggests that the effect on plant growth occurred only after emergence. Effects of direct drilling on soil surface (0- 10 cm) temperature and water content were not important factors reducing plant population or early growth but high soil strength seemed the most likely cause of reduced root extension in the direct drilled seedbed (0-1 5 cm). Reduced root extension had no direct effect on plant water relations or nitrogen concentration in leaves, but there was a small effect on phosphorus concentration. Reduced root growth appears to reduce shoot growth but the mechanisms require further study. The reduced shoot growth led to reduced preanthesis water-use. After anthesis direct drilled crops generally used more water and had higher leaf water potentials than crops in cultivated soil, leading to yield increases in 2 of the years with dry spring conditions. Only in a drought year (1982) was there evidence of direct drilling reducing the maximum depth of rooting and therefore reducing total water-use resulting in lower grain yield (8%). Overall, direct drilling increased grain yields by 2.4% (2.514 v. 2.576 t/ha) compared with conventional tillage, despite the large reduction in early growth.

Poor Early Growth of Wheat Under Direct Drilling

1987 ◽  
Vol 38 (4) ◽  
pp. 791 ◽  
Author(s):  
KY Chan ◽  
JA Mead ◽  
WP Roberts
Keyword(s):  
Shear Strength ◽  
Root Growth ◽  
Biological Properties ◽  
Early Growth ◽  
Undisturbed Soil ◽  
Growth Difference ◽  
Physical Measurements ◽  
The Poor ◽  
Direct Drilling ◽  
Chemical Fallow

Poor early growth of wheat under direct drilling on a hardsetting duplex soil was studied in the light of a range of soil physical and biological properties. Two systems of direct drilling were included in the study: one with a short fallow maintained by herbicide (chemical fallow), and another in which a fallow period was absent and herbicide was applied 1 week before sowing (nil fallow). Plant measurements indicated that the poor early growth observed under both direct drilled systems, as compared to that under conventional cultivation, was not due to poor germination or poor emergence. Rather, it was shown to be a consequence of reduced growth after establishment. Weight per plant measured 64 days after sowing for the conventional, chemical and nil fallow treatments was found to be in the ratio of 3.2: 1.8 : 1.0, respectively. Soil physical measurements during the 9 weeks from sowing indicated that moisture availability was unlikely to be an important factor affecting the observed growth difference for the particular season. Much higher bulk density (1.66 versus 1.35 Mg/m3 at 50-100 mm) and vane shear strength values were found in the undisturbed soil between the drill rows in the top 100 mm of the two direct drilled treatments. Vane shear strength measured in the top 50 mm layer of the direct drilled plots was up to 2.9 times higher between the drill rows than in the drill rows. The poor vegetative growth on the chemical fallow plots was probably caused by restricted root growth in the denser and stronger 0-100 mm depth of undisturbed soil. The poor early vegetative and root growth of wheat in the nil fallow could not be fully explained by the soil physical properties, but indicated the presence of other root inhibitory factors. Our results suggest that one such factor is the presence of inhibitory Eacteria on the roots.

Tillage-induced differences in the growth and distribution of wheat-roots

1992 ◽  
Vol 43 (1) ◽  
pp. 19 ◽  
Author(s):  
KY Chan ◽  
JA Mead
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Root Distribution ◽  
Shoot Growth ◽  
Surface Soil ◽  
Root Length Density ◽  
Soil Layer ◽  
Soil Conditions ◽  
The Poor ◽  
Direct Drilling

Root growth and distribution of wheat under different tillage practices was studied in a 4-year-old tillage experimental site at Cowra, N.S.W. Tillage affected root density as well as distribution. Up to 98 days after sowing, root length density was lower (P < 0.05) in the 0.05-0.10 m layer of the direct-drilled soil than the conventionally cultivated soil. Poor root growth found in direct-drilled soils, which was significantly related to the poor shoot growth, was not caused by soil physical conditions, viz. higher bulk density and soil strength. Rather, biological factors were involved because fumigation completely eliminated the poor shoot growth and significantly increased root length density of the direct drilled soils. Compared to a compaction treatment, roots grown under direct drilling, in addition to having lower density, also had impaired function. Under conventional cultivation, significantly lower root length density was found in the surface soil layer (0-0.05 m) and maximum root length density was found in the 0-05-0.10 m layer. Fumigation did not change the root distribution pattern. This tillage-induced difference in root distribution reflected less favourable surface soil conditions as a result of cultivation, e.g. seedbed slumping, compared to the soil under direct drilling.

Direct drilling effects on early growth of wheat: studies in intact soil cores

1994 ◽  
Vol 34 (2) ◽  
pp. 223 ◽  
Author(s):  
RA Fischer ◽  
Y Kono ◽  
GN Howe
Keyword(s):  
Shoot Growth ◽  
Maximum Growth ◽  
Soil Disturbance ◽  
Early Growth ◽  
Soil Cores ◽  
Disturbed Soil ◽  
Eastern Australia ◽  
Direct Drilling ◽  
Intact Soil Cores ◽  
Intact Soil

Tillage experiments with wheat (Triticum aestivum L.) were conducted at 2 sites in south-eastern Australia: one cool and wet (Murrumbateman), the other warmer and drier (Yanco). Following crop residue removal, direct drilling treatments with complete surface disturbance to 3 cm depth of the medium-textured topsoils (D), or with disturbance only in the narrow seeding slots (DN), were compared with drilling into a surface prepared by cultivating to about 7 cm depth (control). At the 4.5 leaf stage, seedlings from D and DN treatments had less shoot dry weight than the control except at Murrumbateman under very wet post-seeding conditions. Simulation of the above tillage treatments in intact soil Cores from both sites kept under controlled temperature and moisture conditions confirmed that DN treatment, with only 11% of the volume of soil disturbance of the control, reduced early growth, especially at Yanco and if post-sowing conditions were drier. Reduced shoot growth was associated with relatively larger effects on the extent of root exploration. Treatment D, with 43% of the volume of disturbed soil, did not reduce shoot growth relative to the control under any circumstances. Although results suggest a minimum volume of disturbed soil for maximum growth, interactions with biotic stresses as reported recently cannot be ruled out.

scholarly journals 598 Response of Apple Rootstocks to Soil Compaction

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 500A-500
Author(s):  
David C. Ferree
Keyword(s):  
Bulk Density ◽  
Soil Compaction ◽  
Significant Interaction ◽  
Shoot Growth ◽  
Dry Weight ◽  
Soil Bulk Density ◽  
Shoot Length ◽  
Apple Rootstocks ◽  
Compacted Soil ◽  
Different Levels

Container-grown apple trees on a range of rootstocks were exposed to different levels of soil compaction created by changing soil bulk density. In 1998, with soil bulk densities of 1.0, 1.2, and 1.4, there was no interaction of rootstock and soil compaction for shoot growth of `Melrose' trees on 7 rootstocks. However, in 1999, with soil bulk densities of 1.0 and 1.5, a significant interaction on shoot growth did occur with six rootstocks. Shoot length of trees on M.9, M.7, and G.30 were less influenced than G.16, M.26 and MM.106. A bulk density of 1. 5 caused a decrease in dry weight of shoots, leaves, and roots of trees on all rootstocks. Compacted soil resulted in a decrease in leaf concentration of K and B and an increase in Mg and Mn.

scholarly journals Effect of Repeated Short Interval Flooding Events on Root and Shoot Growth of Four Landscape Shrub Taxa

2011 ◽  
Vol 29 (4) ◽  
pp. 220-222
Author(s):  
Kathryne J. Jernigan ◽  
Amy N. Wright
Keyword(s):  
Shoot Growth ◽  
No Reduction ◽  
Southeastern United States ◽  
Short Interval ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Flooding Event ◽  
Root And Shoot Growth ◽  
Size Index ◽  
Flooding Events

Abstract Research was conducted to screen four landscape shrub taxa for tolerance to repeated flooding events. Plants of Fothergilla × intermedia ‘Mt. Airy’ (dwarf witchalder), Ilex verticillata ‘Winter Red’ (winterberry), Clethra alnifolia ‘Ruby Spice’ (summersweet), and Viburnum nudum Brandywine™ (possumhaw) were flooded repeatedly over six weeks for 0 (non-flooded), 3, or 6 days with a draining period of 6 days between each flooding event. The experiment was repeated for a total of two runs. With the exception of F. × intermedia ‘Mt. Airy’, all taxa showed good visual quality and no reduction in root growth in either run, and effects on shoot growth were minimal. Size index of Clethra alnifolia ‘Ruby Spice’ was 27% higher in plants flooded for 0 or 3 days than in plants flooded for 6 days in run 1 only. Shoot dry weight of Ilex verticillata ‘Winter Red’ was actually 11% higher in plants flooded 6 days days than in plants flooded for 0 or 3 days in run 2. Size index of Viburnum nudum Brandywine™ increased with increasing flood length, and plants flooded for 6 days had a 9% higher SI than plants flooded for 0 days in run 1. With the exception of Fothergilla × intermedia L. ‘Mt. Airy’, all taxa appeared tolerant of and even thrived during flooding and would be appropriate shrub selections for a southeastern United States rain garden.

scholarly journals Emergence and Shoot Growth of Cosmos and Marigold from Paclobutrazol-treated Seed

2001 ◽  
Vol 19 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Wallace G. Pill ◽  
James A. Gunter
Keyword(s):  
Growth Medium ◽  
Shoot Growth ◽  
Dry Weight ◽  
Tagetes Patula ◽  
Shoot Height ◽  
Shoot Dry Weight ◽  
Grade 5 ◽  
Treated Seed ◽  
Emergence Percentage ◽  
And Control

Abstract This study was conducted to determine whether treating seeds of ‘Sensation Mixed’ cosmos (Cosmos bipinnatus Cav.) and ‘Bonanza Gold’ marigold (Tagetes patula L.) with paclobutrazol (PB) could suppress seedling growth. Seeds were soaked in solutions of 0, 500 or 1000 mg PB/liter (ppm PB) for 16 hours at 25C (77F) or they were primed [−0.5 MPa (−5 bars) for 7 days at 20C (68F)] in Grade 5 exfoliated vermiculite moistened with 0, 500 or 1000 ppm PB solltuions. Soaked and primed seeds were dried for 1 day at 19C (65F) and 25% relative humidity. These seeds and control (non-treated) seeds were sown into plug cells containing peat-lite. Increasing PB concentration decreased cosmos shoot height at 32 days after planting (DAP), but decreased emergence percentage, responses that were more pronounced with priming than with soaking. A 1 ppm PB growth medium drench [30 ml/cell(0.2 mg PB/cell)] and, to a greater extent a 10 mg PB/liter (ppm PB) shoot spray [2 ml/shoot (0.02 mg PB/shoot)], both applied at 10 DAP, resulted in greater cosmos shoot height suppression at 32 DAP than treatment of seeds with 1000 ppm PB. Soaking marigold seeds in 1000 ppm PB failed to decrease shoot height below those of plants from non-treated seeds at 32 DAP. However, exposure to 1000 ppm PB during priming of marigold seeds resulted in a similar shoot height suppression (13%) as the growth medium drench, and similar shoot dry weight reduction (21%) as the shoot spray. Suppression of shoot growth by this seed treatment was short-term since by five weeks after transplanting into 15 cm (6 in) pots, only marigold plants that had received the growth medium drench or shoot spray were smaller than those of control plants. Treating marigold seeds with 1000 mg ppm PB used about one-fifth the PB used to drench the growth medium.

scholarly journals Evaluation of a Substrate-applied Humectant to Mitigate Drought Stress in Young, Container-grown Plants

2015 ◽  
Vol 33 (3) ◽  
pp. 137-141
Author(s):  
Bruce R. Roberts ◽  
Chris Wolverton ◽  
Samantha West
Keyword(s):  
Drought Stress ◽  
Root Growth ◽  
Shoot Growth ◽  
Dry Weight ◽  
Root:Shoot Ratio ◽  
Xylem Water Potential ◽  
Bedding Plants ◽  
Shoot Dry Weight ◽  
Soilless Substrate ◽  
Absorbing Roots

The efficacy of treating soilless substrate with a commercial humectant was tested as a means of suppressing drought stress in 4-week-old container-grown Zinnia elegans Jacq. ‘Thumbelina’. The humectant was applied as a substrate amendment at concentrations of 0.0, 0.8, 1.6 and 3.2% by volume prior to withholding irrigation. An untreated, well-watered control was also included. The substrate of treated plants was allowed to dry until the foliage wilted, at which time the plants were harvested and the following measurements taken: number of days to wilt (DTW), xylem water potential (ψx), shoot growth (shoot dry weight, leaf area) and root growth (length, diameter, surface area, volume, dry weight). For drought-stressed plants grown in humectant-treated substrate at concentrations of 1.6 and 3.2%, DTW increased 25 and 33%, respectively. A linear decrease in ψx was observed as the concentration of humectant increased from 0.0 to 3.2%. Linear trends were also noted for both volumetric moisture content (positive) and evapotranspiration (negative) as the concentration of humectant increased. For non-irrigated, untreated plants, stress inhibited shoot growth more than root growth, resulting in a lower root:shoot ratio. For non-irrigated, humectant-treated plants, the length of fine, water-absorbing roots increased linearly as humectant concentration increased from 0.0 to 3.2%. Using humectant-amended substrates may be a management option for mitigating the symptoms of drought stress during the production of container-grown bedding plants such as Z. elegans.

scholarly journals Seedling Developmental Stage at Transplanting Affects Growth and Flowering of Medallion Flower and Globe Amaranth

2015 ◽  
Vol 33 (2) ◽  
pp. 53-57 ◽  
Author(s):  
G.J. Keever ◽  
J.R. Kessler ◽  
G.B. Fain ◽  
D.C. Mitchell
Keyword(s):  
Shoot Growth ◽  
Growth Index ◽  
Dry Weight ◽  
Development Stage ◽  
Seedling Development ◽  
Bedding Plants ◽  
Shoot Dry Weight ◽  
Flower Growth ◽  
Root Restriction ◽  
Experimental Runs

A study was conducted to determine how seedling development stage at transplanting from plug flats into small pots affected growth and flowering of two commonly grown bedding plants. Seeds of Showstar® medallion flower and ‘Las Vegas Pink’ globe amaranth were sown in 392-cell flats on five dates for each of two experimental runs before transplanting into 8.9 cm (3.5 in) cubic pots. At transplanting of both species, plant height, node count and shoot dry weight increased as days from sowing to transplanting increased and there was no visible cessation in shoot growth due to root restriction. Time to first flower from transplanting decreased linearly with both species in both runs, except with medallion flower in the second run, as time from sowing to transplanting increased. In contrast, time to flower of both species from sowing increased linearly as time from sowing to transplanting increased. However, the magnitude of the increase or decrease in time to flower differed between the two runs indicating that other factors, most likely light intensity and duration, besides node counts were affecting time to flower. Globe amaranth height and growth index and medallion flower growth index at first flower decreased as time from sowing to transplanting increased, whereas medallion flower height was not affected by time from sowing to transplanting.

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