Restricted growth of lupin and wheat roots in the sandy A horizon of a yellow duplex soil

1993 ◽  
Vol 44 (6) ◽  
pp. 1273 ◽  
Author(s):  
M Dracup ◽  
PJ Gregory ◽  
RK Belford
Keyword(s):  
Root Growth ◽  
Crop Yields ◽  
Frictional Resistance ◽  
Mechanical Impedance ◽  
High Strength ◽  
Root Penetration ◽  
Good Growth ◽  
Wheat Roots ◽  
Poor Growth ◽  
Local Soil

Yellow duplex soils are the dominant soil type in the cropping region of Western Australia, but crop yields on these soils are often variable and below potential. We are seeking to understand the causes of the spatially variable crop growth, and a preliminary study conducted in 1988 at a site east of Beverley indicated that variable shoot growth was associated with variable early (< 6 weeks after sowing) root growth in the sandy A horizon. The present study aimed to identify the constraints to early root growth by locating the position in the A horizon where root growth becomes restricted and measuring the local soil properties. In poor growth areas, root penetration slowed markedly at about 15 cm (about 2 weeks after sowing), while in the good growth areas roots continued to grow downwards at about 8 mm day-1 for lupin and 4 mm day-' for wheat. The soil was a particularly difficult environment for root growth, with generally low pH, low K and B, low porosity and aeration and high strength. Roots in poor growth areas appeared to experience greater mechanical impedance than in the good areas, most likely due to much lower clay contents leading to higher frictional resistance to particle movement or less stability of soil pores created by past roots or fauna.

Constraints to root growth of wheat and lupin crops in duplex soils

1992 ◽  
Vol 32 (7) ◽  
pp. 947 ◽  
Author(s):  
M Dracup ◽  
RK Belford ◽  
PJ Gregory
Keyword(s):  
Root Growth ◽  
Western Australia ◽  
Crop Production ◽  
Chemical Properties ◽  
Mechanical Impedance ◽  
Lupinus Angustifolius ◽  
Rooting Depth ◽  
Wheat Roots ◽  
High Ph ◽  
Penetrometer Resistance

Duplex soils constitute about 60% of the cropping region of Western Australia and are usually cropped with wheat or lupins. Extensive and deep root growth is particularly important to crop production on these soils, because the nutrient- and water-holding capacities of the A horizon are frequently low. However, properties of the soils and the Mediterranean-type climate impose several constraints to root growth. Physical and chemical properties of duplex soils are spatially variable, leading to pronounced variation (from metres to tens of metres) in the growth of roots and shoots. Both the A and B horizons often impede root growth mechanically, with bulk density and penetrometer resistance frequently exceeding 1.8 Mg/m3 and 2 MPa, respectively. Also, saturated conductivities of the B horizon are often <0.01 m/day, leading to waterlogging. Topsoil acidity is often a problem in lighttextured A horizons, with pH declining about 0.1 unit each decade in yellow duplex soils near Beverley, Western Australia, where pH is already usually <4.8. Conversely, in the B horizon of red-brown earths and, sometimes, yellow duplex soils, pH >7 restricts growth of roots of Lupinus angustifolius. Major constraints to root growth often occur together (e.g. waterlogging with acidity, salinity, or mechanical impedance), and this exacerbates problems of root growth and necessitates identification and amelioration of the particular combination of constraints to improve root growth. Although L. angustifolius is often grown on duplex soils, its roots are not suited to these soils. Rooting depth is restricted, and unlike wheat roots, those of L. angustifolius are poorly adapted to ramifying through the soil for efficient water and nutrient extraction. Lupinus angustifolius is also particularly sensitive to high pH, salinity, and, probably, waterlogging. Other species of lupin which are more tolerant of high pH (e.g. L. pilosus) and waterlogging (e.g. L. luteus) may be more appropriate on duplex soils.

SOIL LIMITATIONS TO CROP PRODUCTIVITY IN CANADA

1983 ◽  
Vol 63 (1) ◽  
pp. 23-32 ◽  
Author(s):  
M. H. MILLER
Keyword(s):  
Water Stress ◽  
Root Growth ◽  
Management Practices ◽  
Crop Yields ◽  
Nutrient Deficiency ◽  
Mechanical Impedance ◽  
Crop Productivity ◽  
Light Interception ◽  
Physiological Factor ◽  
Water Holding

The highest crop yields obtained in a region are usually much lower than the potential yields estimated from light interception. The roles of soil characteristics and soil-root interrelations as causes of the failure to achieve the potential yields are discussed. It is concluded that, on our best soils, it is possible to overcome all limitations with the exception of soil temperature and possibly some mechanical impedance to root growth. It is suggested that some physiological factor other than light interception is responsible for the failure to obtain the potential yields. Many soils possess characteristics which do restrict yields. Occurrences of acidity, poor aeration, nutrient deficiency, and water stress due to poor soil structure in various regions of Canada are discussed. It is concluded that the most difficult limitations to overcome are those associated with fine-textured soils with compact, poorly structured subsoils. These soils are frequently wet in the spring delaying planting operations, and/or causing crop losses due to poor aeration. In the summer, crops on these soils may suffer from water stress because of low available water holding capacity and restricted root growth. Although management practices can overcome many limitations, improper management may also lead to loss in productivity. Increases in salinity and soil erosion are serious problems in Canada.Key words: Root-soil interactions, root growth, nutrient absorption, soil acidity, soil aeration, soil-plant water relations.

Effects of organic matter and time of incorporation on root development of tropical maize seedlings

2008 ◽  
Vol 56 (2) ◽  
pp. 169-178
Author(s):  
U. Sangakkara ◽  
S. Nissanka ◽  
P. Stamp
Keyword(s):  
Organic Matter ◽  
Root Growth ◽  
Rice Straw ◽  
Organic Materials ◽  
Gliricidia Sepium ◽  
Quality Parameters ◽  
Control Treatment ◽  
Poor Growth ◽  
Time Of Application ◽  
The Impact

Smallholders in the tropics add different organic materials to their crops at different times, based on the availability of materials and labour. However, the time of application could have an effect on the establishment and early growth of crops, especially their root systems, which has not yet been clearly identified. This paper presents the results of a study conducted under greenhouse conditions using soils from a field treated with three organic materials at 4 or 2 weeks before or at the planting of maize seeds, corresponding to the times that tropical smallholders apply these materials. The organic materials used were leaves of Gliricidia sepium and Tithonia diversifolia or rice straw, incorporated at a rate equivalent to 6 Mt ha −1 . A control treatment where no organic matter was added was used for comparison. The impact of the treatments on soil properties at the planting of maize seed and detailed root analysis based on root lengths were carried out until the last growth stage (V4). The addition of organic matter improved the soil characteristics, and the impact of adding Gliricidia leaves was most pronounced when incorporated 2 weeks before planting. The benefits of leaves of Tithonia or rice straw on soil quality parameters were clearly evident when added 4 weeks before planting. Organic matter enhanced the root number, root length, root growth rate and branching indices. All the organic materials suppressed the growth of maize roots when applied at planting, suggesting the existence of allelopathic effects, which could result in poor growth. The most benefits in terms of root growth were observed with Tithonia .

scholarly journals Imaging local soil kinematics during the first days of maize root growth in sand

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Floriana Anselmucci ◽  
Edward Andò ◽  
Gioacchino Viggiani ◽  
Nicolas Lenoir ◽  
Chloé Arson ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Shear Strain ◽  
Root System ◽  
Capillary Rise ◽  
Image Correlation ◽  
Root Tip ◽  
Soil System ◽  
Local Soil ◽  
Initial Soil

AbstractMaize seedlings are grown in Hostun sand with two different gradings and two different densities. The root-soil system is imaged daily for the first 8 days of plant growth with X-ray computed tomography. Segmentation, skeletonisation and digital image correlation techniques are used to analyse the evolution of the root system architecture, the displacement fields and the local strain fields due to plant growth in the soil. It is found that root thickness and root length density do not depend on the initial soil configuration. However, the depth of the root tip is strongly influenced by the initial soil density, and the number of laterals is impacted by grain size, which controls pore size, capillary rise and thus root access to water. Consequently, shorter root axes are observed in denser sand and fewer second order roots are observed in coarser sands. In all soil configurations tested, root growth induces shear strain in the soil around the root system, and locally, in the vicinity of the first order roots axis. Root-induced shear is accompanied by dilative volumetric strain close to the root body. Further away, the soil experiences dilation in denser sand and compaction in looser sand. These results suggest that the increase of porosity close to the roots can be caused by a mix of shear strain and steric exclusion.

Root growth of lupins is more sensitive to waterlogging than wheat

2011 ◽  
Vol 38 (11) ◽  
pp. 910 ◽  
Author(s):  
Helen Bramley ◽  
Stephen D. Tyerman ◽  
David W. Turner ◽  
Neil C. Turner
Keyword(s):  
Root Growth ◽  
Oxygen Deficiency ◽  
Triticum Aestivum L ◽  
Wheat Root ◽  
Lupinus Luteus ◽  
Apical Region ◽  
Basal Region ◽  
Yellow Lupin ◽  
Wheat Roots ◽  
Root Death

In south-west Australia, winter grown crops such as wheat and lupin often experience transient waterlogging during periods of high rainfall. Wheat is believed to be more tolerant to waterlogging than lupins, but until now no direct comparisons have been made. The effects of waterlogging on root growth and anatomy were compared in wheat (Triticum aestivum L.), narrow-leafed lupin (Lupinus angustifolius L.) and yellow lupin (Lupinus luteus L.) using 1 m deep root observation chambers. Seven days of waterlogging stopped root growth in all species, except some nodal root development in wheat. Roots of both lupin species died back progressively from the tips while waterlogged. After draining the chambers, wheat root growth resumed in the apical region at a faster rate than well-drained plants, so that total root length was similar in waterlogged and well-drained plants at the end of the experiment. Root growth in yellow lupin resumed in the basal region, but was insufficient to compensate for root death during waterlogging. Narrow-leafed lupin roots did not recover; they continued to deteriorate. The survival and recovery of roots in response to waterlogging was related to anatomical features that influence internal oxygen deficiency and root hydraulic properties.

Interpopulation variation in male parr maturation of anadromous brown trout (Salmo trutta) in Norway

1990 ◽  
Vol 68 (9) ◽  
pp. 1983-1987 ◽  
Author(s):  
Jan Henning L'Abée-Lund ◽  
Arne Johan Jensen ◽  
Bjørn Ove Johnsen
Keyword(s):  
Fresh Water ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Mature Male ◽  
Good Growth ◽  
Effective Population ◽  
Poor Growth ◽  
Total Length ◽  
Mature Male Parr ◽  
Smolt Age

We studied male parr maturation in anadromous brown trout in nine Norwegian rivers. Mean age at maturity increased from 1.5 years in southern populations to 5.2 years in northern populations, but the latitudinal correlation was not significant. Mean age of male parr at maturity was negatively correlated with mean total length of 0- and 1-year-old parr. The proportion of mature male parr varied between 0.06 and 0.6 among populations, and was positively correlated with mean total length of 0- and 1-year-old parr. The proportion of mature male parr decreased significantly with increasing mean smolt age of males. This indicates that in populations with relatively poor growth in fresh water (i.e., high smolt age) males mainly spawn as sea-run migrants, whereas in populations with relatively good growth in fresh water the mature male parr potentially contribute twice to the genetic makeup of the population, further increasing the effective population size.

Effects of subsoil calcium on the root growth of some lucerne genotypes (Medicago sativa L.) in acidic soil profiles

1977 ◽  
Vol 28 (4) ◽  
pp. 629 ◽  
Author(s):  
JR Simpson ◽  
A Pinkerton ◽  
J Lazdovskis
Keyword(s):  
Root Growth ◽  
Lower Layer ◽  
Dry Weight ◽  
Solution Culture ◽  
Acidic Soil ◽  
Root Penetration ◽  
Soil Calcium ◽  
Medicago Sativa L ◽  
Total Dry Weight ◽  
Final Harvest

The root growth of lucerne was examined in an acidic soil profile modified by varying additions of calcium carbonate to different layers of the subsoil. Root growth responded strongly to changes in the concentration of exchangeable soil calcium. Symptoms of thickening, distortion and poor lateral formation occurred under low calcium treatments. The results were in agreement with the interacting effects of calcium (at 0.5–5.0mM) and aluminium ions (at 0–20,µM) on lucerne in separate solution culture experiments. Differences in root penetration were observed between three lucerne clones selected from the cultivars Hunter River and Siro Peruvian. At the first harvest, the magnitude of these differences was increased by the addition of lime to the profiles. The three genotypes produced similar total dry weight yields, but differed in their distribution of growth between shoots and roots. This distribution was not affected by the addition of lime to the subsoil. However, the length of roots in the lower layer of the profile ( > 60 cm depth) was more responsive to subsoil treatment than was total dry weight. At the final harvest, the shoot yields of two genotypes were affected by lime treatments, but that of the deepest-rooted genotype was not. The results suggest that improved genotypes could be selected from Australian lucernes for establishment in areas with acidic subsoils, but that selection on root penetration alone would not necessarily lead to increased shoot yields.

Root growth and anchorage by transplanted ‘Tifgreen’ (Cynodon dactylon x C. transvaalensis) turfgrass

2014 ◽  
Vol 41 (3) ◽  
pp. 276
Author(s):  
Jeffrey S. Amthor ◽  
James B. Beard
Keyword(s):  
Root Growth ◽  
Cynodon Dactylon ◽  
Early Spring ◽  
Late Spring ◽  
Loamy Sand ◽  
Root Penetration ◽  
Vertical Force ◽  
Loamy Sand Soil ◽  
Root Anchorage ◽  
Anchoring Strength

Field experiments quantified factors affecting root growth and anchorage by transplanted ‘Tifgreen’ (Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy) sod, a globally important warm-season C4 turfgrass. Vertical force required to detach recently transplanted sod from underlying soil was the measure of root anchoring strength. In early spring, date of sod harvest and transplantation was important to root growth and anchorage measured 30 days after transplantation. Delaying sod harvest/transplantation by about a month after the end of the winter shoot dormancy period increased root anchoring strength 200% and root dry mass 640% during the 30 days after sodding. The strong effect of early-spring sodding date on root anchorage was related to cumulative thermal time before sod harvesting. Root anchoring strength was directly proportional to the number, but not mass, of roots produced by transplanted sod. In late spring, anchoring of sod to very firm traffic-compacted clay was 87% greater than to loamy sand, measured 14 days after sodding. N-P-K fertilisation did not affect late-spring sod anchorage to loamy sand soil, measured 18 days after sodding, but did enhance shoot density and colour. Sod root penetration into a silt loam soil was unaffected by an initially dry surface layer when sufficient irrigation was used. Overall, root anchorage by transplanted Tifgreen sod was similar to, or greater than, values reported for cool-season C3 turfgrasses in similar circumstances.

scholarly journals Looseness Monitoring of Bolted Spherical Joint Connection Using Electro-Mechanical Impedance Technique and BP Neural Networks

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1906 ◽  
Author(s):  
Jing Xu ◽  
Jinhui Dong ◽  
Hongnan Li ◽  
Chunwei Zhang ◽  
Siu Chun Ho
Keyword(s):  
Neural Networks ◽  
Lead Zirconate Titanate ◽  
Back Propagation ◽  
Mechanical Impedance ◽  
High Strength ◽  
Lead Zirconate ◽  
Spherical Joint ◽  
High Strength Bolt ◽  
Space Grid ◽  
Joint Connection

The bolted spherical joint (BSJ) has wide applications in various space grid structures. The bar and the bolted sphere are connected by the high-strength bolt inside the joint. High-strength bolt is invisible outside the joint, which causes the difficulty in monitoring the bolt looseness. Moreover, the bolt looseness leads to the reduction of the local stiffness and bearing capacity for the structure. In this regard, this study used the electro-mechanical impedance (EMI) technique and back propagation neural networks (BPNNs) to monitor the bolt looseness inside the BSJ. Therefore, a space grid specimen having bolted spherical joints and tubular bars was considered for experimental evaluation. Different torques levels were applied on the sleeve to represent different looseness degrees of joint connection. As the torque levels increased, the looseness degrees of joint connection increased correspondingly. The lead zirconate titanate (PZT) patch was used and integrated with the tubular bar due to its strong piezoelectric effect. The root-mean-square deviation (RMSD) of the conductance signatures for the PZT patch were used as the looseness-monitoring indexes. Taking RMSD values of sub-frequency bands and the looseness degrees as inputs and outputs respectively, the BPNNs were trained and tested in twenty repeated experiments. The experimental results show that the formation of the bolt looseness can be detected according to the changes of looseness-monitoring indexes, and the degree of bolt looseness by the trained BPNNs. Overall, this research demonstrates that the proposed structural health monitoring (SHM) technique is feasible for monitoring the looseness of bolted spherical connection in space grid structures.

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