scholarly journals The effect of seed size and depth of seeding on the emergence of grassland plants

1962 ◽  
Vol 34 (1) ◽  
pp. 18-25
Author(s):  
K. Multamäki
Keyword(s):  
Seed Size ◽  
Growth And Development ◽  
Soil Surface ◽  
Considerable Proportion ◽  
Initial Growth ◽  
Grassland Plants ◽  
Heavy Clay ◽  
Valuable Characteristic ◽  
Different Depths ◽  
Growing Conditions

The seeding of grasslands in Finland fails relatively often owing to the difficult growing conditions for the young seedlings. As a result, the stands are in many cases rather thin and must sometimes be ploughed up without giving any yield at all. One of the factors hampering the initial growth and development of grassland plants is unsuitable sowing. Thus, for instance, a considerable proportion of the seed may be sown at too great a depth, which prevents the seedlings from emerging. On the other hand, the seeds scattered upon the soil surface will also meet difficulties in their germination stage, especially in dry periods. Hence, a valuable characteristic for a grassland plant seedling would be the ability to surmount the various obstacles arising from deficient seeding measures. The object of the present investigation is to study the emergence capacity of some grassland plants, the majority of which are grown extensively in Finland. For this purpose, seeds of the plants to be studied were sown on soil surface as well as at different depths. The influence of seed size in this connexion was examined, too. All the studies concerned were carried out in the greenhouse. The soil used as substrata in these experiments was heavy clay, representing the valuable arable soil type occurring fairly commonly, especially in Southwest Finland.

LYSIMETERS WITH RAINFALL AND SOIL WATER CONTROL

1971 ◽  
Vol 2 (2) ◽  
pp. 79-92 ◽  
Author(s):  
K. J. KRISTENSEN ◽  
H. C. ASLYNG
Keyword(s):  
Soil Moisture Content ◽  
Soil Depth ◽  
Irrigation System ◽  
Drainage System ◽  
Soil Surface ◽  
Trickle Irrigation ◽  
Water Control ◽  
Radiation Equipment ◽  
Different Depths ◽  
Growth Experiments

The lysimeter installation described comprises 36 concrete tanks each with a soil surface of 4 m2. The installation is useful for plant growth experiments under natural conditions involving different treatment combined with various controlled water supplies. The ground installation is at least 20 cm below the soil surface and tillage can be done with field implements. The lysimeter tanks are provided with a drainage system which can drain the soil at the bottom (100 cm depth) to a tension of up to 100 cm. A constant ground-water table at less than 100 cm soil depth can also be maintained. The soil moisture content at different depths is determined from an underground tunnel by use of gamma radiation equipment in metal tubes horizontally installed in the soil. Rainfall is prevented by a movable glass roof automatically operated and controlled by a special rain sensor. Water is applied to the soil surface with a special trickle irrigation system consisting of a set of plastic tubes for each lysimeter tank and controlled from the tunnel. Fertilizers in controlled amount can be applied with the irrigation water.

Effect of tiller age and time of nitrogen stress on seed production of Paspalum plicatulum

1973 ◽  
Vol 81 (2) ◽  
pp. 219-229 ◽  
Author(s):  
P. A. Chadhokar ◽  
L. R. Humphreys
Keyword(s):  
Ammonium Nitrate ◽  
Seed Size ◽  
Seed Yield ◽  
Growth And Development ◽  
Nitrogen Nutrition ◽  
Development Stage ◽  
Nitrogen Supply ◽  
Nitrogen Stress ◽  
Floral Initiation ◽  
Final Maturation

SummaryPaspalum plicatulum was grown at Brisbane in boxes of sand receiving basal nutrients and frequent irrigation; weekly levels of ammonium nitrate application were varied according to growth and development stage.The rate of tiller appearance increased to a maximum 40–50 days after sowing and almost ceased thereafter. Tiller leaf number, survival, fertility, inflorescence branching, seeds per raceme and seed size were positively related to tiller age. Young tillers were more sensitive to variations in nitrogen supply than old tillers.Adequate nitrogen nutrition during the vegetative phase from sowing to floral initiation (93 days) increased tiller and hence inflorescence density; increased inflorescence branching was compensated by fewer seeds per raceme. Good nitrogen nutrition during the phase from floral initiation to inflorescence exsertion (142 days) increased survival of late-formed tillers and hence inflorescence density; inflorescence branching, seeds per raceme and seed size were also increased. Nitrogen stress during the final maturation phase did not affect seed yield.

scholarly journals Initial growth and development of southern sandbur based on thermal units

2014 ◽  
Vol 32 (2) ◽  
pp. 335-343 ◽  
Author(s):  
E.C.R. Machado ◽  
R.S.O. Lima ◽  
A.P.P. Silva ◽  
B.S. Marques ◽  
M.F. Gonçalves ◽  
...  
Keyword(s):  
Growth And Development ◽  
Dry Matter ◽  
Integrated Management ◽  
Base Temperature ◽  
Initial Growth ◽  
Agricultural Systems ◽  
Degree Days ◽  
Flowering Stage ◽  
Weed Biology ◽  
Best Fit

Availability of basic information on weed biology is an essential tool for designing integrated management programs for agricultural systems. Thus, this study was carried out in order to calculate the base temperature (Tb) of southern sandbur (Cenchrus echinatus), as well as fit the initial growth and development of the species to accumulated thermal units (growing degree days - GDD). For that purpose, experimental populations were sown six times in summer/autumn conditions (decreasing photoperiod) and six times in winter/spring condition (increasing photoperiod). Southern sandbur phenological evaluations were carried out, on alternate days, and total dry matter was measured when plants reached the flowering stage. All the growth and development fits were performed based on thermal units by assessing five base temperatures, as well as the absence of it. Southern sandbur development was best fit with Tb = 12 ºC, with equation y = 0,0993x, where y is the scale of phenological stage and x is the GDD. On average, flowering was reached at 518 GDD. Southern sandbur phenology may be predicted by using mathematical models based on accumulated thermal units, adopting Tb = 12 ºC. However, other environmental variables may also interfere with species development, particularly photoperiod.

Ethylene: A Witchweed Seed Germination Stimulant

Weed Science ◽  
1975 ◽  
Vol 23 (5) ◽  
pp. 433-436 ◽  
Author(s):  
Robert E. Eplee
Keyword(s):  
United States ◽  
Seed Germination ◽  
Clay Soil ◽  
Soil Surface ◽  
Field Studies ◽  
The United States ◽  
Major Contributor ◽  
Single Treatment ◽  
Striga Asiatica ◽  
Heavy Clay

Ethylene gas (C2H4) was found to stimulate the germination of witchweed [Striga asiatica(L.) O. Kuntze] seeds. Ethylene diffuses greater than 120 cm horizontally from point of injection and more than 90 cm below the soil surface. Rates of 0.42 kg/ha induced germination of witchweed seeds in sandy soil; but 1.1 kg/ha is required on a heavy clay soil. Witchweed seeds respond to ethylene after a period of preconditioning that is necessary to break dormancy. Under field conditions in the Carolinas, maximum response of seeds to ethylene occurs between late April and late July. Field studies indicate a 90% reduction in viable witchweed seeds occurs where a single treatment with ethylene has been applied. The use of ethylene appears now to be a major contributor toward the eventual eradication of witchweed from the United States.

scholarly journals Does seed size affect the germination rate and seedling growth of peanut under salinity and water stress?

2019 ◽  
Vol 49 ◽  
Author(s):  
Fábio Steiner ◽  
Alan Mario Zuffo ◽  
Aécio Busch ◽  
Tiago de Oliveira Sousa ◽  
Tiago Zoz
Keyword(s):  
Water Stress ◽  
Seed Size ◽  
Seedling Growth ◽  
Germination Rate ◽  
Stress Conditions ◽  
Medium Size ◽  
Dry Matter Accumulation ◽  
Initial Growth ◽  
Sowing Time ◽  
Important Indicator

ABSTRACT Seed size is an important indicator of physiological quality, since it may affect seed germination and seedling growth, especially under stress conditions. This study aimed to investigate the effects of seed size on germination and initial seedling growth, under salinity and water stress conditions. The treatments were arranged in a completely randomized design, in a 3 × 3 factorial scheme: three seed size classes (small, medium and large) and three stress treatments (control, saline or water stress), with four replicates. Water and salt stresses do not reduce the germination rate of medium and large seeds; however, the germination rate of small seeds is reduced under salt stress conditions. Drought stress drastically reduces the shoot growth of seedlings regardless of seed size, whereas root growth is higher in seedlings from medium and large seeds under water stress conditions. Under non-stressful environments, the use of large seeds is preferable, resulting in more vigorous seedlings with a greater dry matter accumulation. Medium-size seeds are more adapted to adverse environmental conditions and, therefore, should be used under conditions of water shortage and salt excess in the soil at sowing time. Seedlings are more tolerant to salinity than to water stress during the germination stage and initial growth under laboratory conditions.

Effect of triapenthenol plant-growth regulator on canola height, yield, side branches and pod density

1992 ◽  
Vol 72 (4) ◽  
pp. 1153-1156 ◽  
Author(s):  
K. J. Kirkland
Keyword(s):  
Brassica Napus ◽  
Plant Growth ◽  
Field Experiment ◽  
Plant Height ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Growth And Development ◽  
Management Tool ◽  
Brassica Napus L ◽  
Growing Conditions

A 3-yr field experiment was conducted at the Scott Experimental Farm to determine the effect of the growth regulator, triapenthenol, on the growth and development of Argentine canola (Brassica napus L.). Triapenthenol reduced plant height 25–45 cm under optimal growing conditions. Increases in yield, branches and total pods were observed. Application at the bud stage was more effective than earlier treatment in the rosette. It was concluded that triapenthenol application to canola could be a useful management tool, particularly under optimal growing conditions.Key words: Canola, growth regulator, RSW-0411, lodging

A spatial analysis of lateral and vertical fluxes of water associated with a perched watertable in a duplex soil

Soil Research ◽  
2000 ◽  
Vol 38 (4) ◽  
pp. 879 ◽  
Author(s):  
J. Eastham ◽  
P. J. Gregory ◽  
D. R. Williamson
Keyword(s):  
Spatial Analysis ◽  
Water Movement ◽  
Soil Surface ◽  
Vertical Movement ◽  
Climatic Conditions ◽  
Clay Layer ◽  
Lateral Movement ◽  
Vertical Fluxes ◽  
Heavy Clay ◽  
Experimental Plots

Rates of lateral and vertical movement of water were investigated when severe waterlogging occurred as a result of a perched watertable over a clay subsoil in a duplex soil on a low (1.6%) slope in Western Australia. The severity of waterlogging and both the lateral and vertical fluxes of water at the 1.4 ha site were very spatially variable. Lateral water movement occurred in response to topographical gradients in the soil surface and the depth of the clay layer. As a result of this lateral redistribution of water, the depth of the watertable was greater in some areas, causing higher rates of vertical water loss (1.6–1.7 mm/day) compared with the rest of the site (1.2–1.5 mm/day). Net gains or losses in water in experimental plots at the site due to lateral flow were 1–2 orders of magnitude smaller than vertical losses. Net lateral losses were less than 0.3 mm/day, but vertical losses ranged from 1.2 to 1.7 mm/day. We conclude that vertical drainage beneath crops growing on a duplex soil with a heavy clay subsoil can be significant when a head of water develops under climatic conditions conducive to waterlogging. In contrast, net lateral movement was generally small because of the low slope at the site (gradient of 0.016), and is likely to be insignificant at this site and other sites with duplex soils on similarly low slopes.

scholarly journals Phytotoxic Potential of the Crude Extract and Leaf Fractions of Machaerium hirtum on the Initial Growth of Euphorbia heterophylla And Ipomoea grandifolia

2019 ◽  
Vol 37 ◽  
Author(s):  
G.R. XIMENEZ ◽  
S.M.O. SANTIN ◽  
M.C. IGNOATO ◽  
L.A. SOUZA ◽  
L.H. PASTORINI
Keyword(s):  
Crude Extract ◽  
Growth And Development ◽  
Leaf Extract ◽  
Morning Glory ◽  
Initial Growth ◽  
Weed Species ◽  
Know How ◽  
Anatomical Analysis ◽  
Crude Leaf Extract ◽  
Root Necrosis

ABSTRACT: Allelopathy is the term used to define any process involving secondary metabolites produced by plants and microorganisms that influence growth and development of agrobiological systems. Currently, it is sought to find allelochemicals of interest and know how to apply them in bio-herbicides to combat weeds. In this study, the effects of the crude leaf extract and fractions of Machaerium hirtum (Vell.) Stellfeld were analyzed on Euphorbia heterophylla L. (wild poinsettia) and Ipomoea grandifolia (Dammer) O’Donell (morning glory), as well as the occurrence of morphoanatomical changes. For this, 0.04 g of the crude extract and fractions were solubilized and diluted (50 mL) to concentrations of 0.1, 0.2, 0.4, and 0.8 g L-1 (m/v). Initial growth tests were performed on Petri dishes containing two paper sheets and seedlings of weed species with the respective treatments, being maintained in a germination chamber for 48 hours at 25 oC. Distilled water was used as a control. Shoot and root length was assessed in the initial growth. The percentage of inhibition was calculated based on the values obtained in the initial growth bioassays. Morphologically altered wild poinsettia seedlings were fixed and sectioned transversely for anatomical analysis. The results indicated significant changes in length, being wild poinsettia seedlings more sensitive when compared to those of morning glory. Morphologically altered seedlings presented root necrosis as the most frequent symptom. Anatomically, parenchymatic cells of the hypocotyl and roots of wild poinsettia seedlings presented smaller and irregularly shaped cells when compared to the control, causing significant reductions in the measured parameters.

Sign in / Sign up

Export Citation Format

Share Document