Effect of soil moisture and fertilizer application on clonal growth and reproduction in a tristylous weed, Lythrum salicaria

1997 ◽  
Vol 75 (1) ◽  
pp. 46-60 ◽  
Author(s):  
Tarun K. Mal ◽  
Jon Lovett-Doust ◽  
Lesley Lovett-Doust
Keyword(s):  
Soil Moisture ◽  
Clonal Growth ◽  
Spatial Separation ◽  
Field Studies ◽  
Fertilizer Application ◽  
Lythrum Salicaria ◽  
Relative Mass ◽  
Total Length ◽  
Proportional Allocation ◽  
Growth And Reproduction

Clonal growth and reproduction in tristylous Lythrum salicaria L. were examined experimentally, using cloned genotypes of each of the three flower morphs, in field studies involving four moisture and three nutrient treatments. Clonal growth was measured in terms of diameter of clones, number of ramets per clone, and total length of ramets, and an index of reproduction was recorded as the total length of infructescence per clone. Neither clonal growth nor reproduction differed significantly among flower morphs, but both differed significantly as a consequence of both moisture and nutrient treatments. The pattern of seasonal growth indicates that ramet production was restricted mainly to the beginning of the season following vigorous vegetative growth. Although flowering began in June, it was restricted to plants in drier treatments in the water-gradient experiment. Characters intrinsic to tristyly (such as lengths of styles and stamens, and allocation of biomass to stamens and pistil) differed significantly among morphs. Soil moisture levels but not fertilizer treatments significantly affected the size of floral structures and biomass. Although absolute levels of biomass allocation to whole flowers and to attractive structures did not differ significantly among morphs, relative allocation to stamens increased progressively from long morph to mid-morph to short morph, with a corresponding decrease in relative mass of pistil. Although proportional allocation differed significantly among morphs, it was unaffected by moisture treatment, suggesting tight genetic control of herkogamy (spatial separation between anther and stigma). This should maintain the floral polymorphism in different ecological conditions. Key words: Lythrum salicaria, nutrient and water gradients, heterostyly, floral morphometry, floral allocation, clonal growth, sexual reproduction.

Morph frequencies and floral variation in a heterostylous colonizing weed, Lythtum salicaria

1997 ◽  
Vol 75 (7) ◽  
pp. 1034-1045 ◽  
Author(s):  
Tarun K. Mal ◽  
Jon Lovett-Doust
Keyword(s):  
Clonal Growth ◽  
Significant Interaction ◽  
Spatial Separation ◽  
Lythrum Salicaria ◽  
Purple Loosestrife ◽  
Frequency Of Occurrence ◽  
Floral Variation ◽  
Morphometric Analyses ◽  
Herbaceous Perennial ◽  
Morph Frequency

Lythrum salicaria (purple loosestrife) is an exotic weed that arrived in North America from Europe during the early 1800s. It is a herbaceous perennial with a trimorphic breeding system. Seventy-four populations of L. salicaria were surveyed from Windsor, Ontario, to the Gaspé Peninsula in Quebec. Fifty of the populations were significantly anisoplethic (i.e., unequal frequencies of the three flower morphs), including 10 populations that were nontrimorphic. Populations with fewer than 100 plants tended to have one or even two morphs missing. Although larger populations rarely lacked a morph, they did show significantly skewed morph frequencies. Indices of clonal size, such as number of ramets per genet and genet diameter, differed significantly among sites, and clonal growth also showed significant interaction between morph and site. One-way analyses of variance indicated that morphs differed in terms of either number of ramets per genet or genet diameter in 16% of populations. Morphometric analyses of flowers from 49 populations showed significant variability in floral traits among genets, flower morphs, and sites. Results indicated frequent reduction in herkogamy (spatial separation between anther and stigma), with variant flowers having very little or no stigma–anther separation. Mean stigma–anther separation was lowest in the mid-morph individuals, followed by the short and long morphs. Correspondingly, the frequency of variant flowers was greatest in mid-morph individuals and least in long-morph individuals. Isoplethic and anisoplethic populations did not differ, for any morph, in the frequency of occurrence of these variant flowers. Key words: Lythrum salicaria, purple loosestrife, isoplethy, morph frequency, heterostyly, variant flowers, stigma–anther separation.

Laboratory and field studies on the degradation of fipronil in a soil

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1095 ◽  
Author(s):  
Guang-Guo Ying ◽  
Rai Kookana
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Field Studies ◽  
Transformation Product ◽  
Laboratory Studies ◽  
The Third ◽  
High Soil Moisture ◽  
Sulfone Derivatives

Degradation of a new insecticide/termiticide, fipronil, in a soil was studied in the laboratory and field. Three metabolites of fipronil (desulfinyl, sulfide, and sulfone derivatives) were identified from soils after treatment. Laboratory studies showed that soil moisture content had a great effect on the degradation rate of fipronil and products formed. High soil moisture contents (>50%) favored the formation of a sulfide derivative of fipronil by reduction, whereas low soil moisture (<50%) and well-aerated conditions favored the formation of fipronil sulfone by oxidation. Microorganisms in soil accelerated the degradation of fipronil to sulfide and sulfone derivatives. The third transformation product, a desulfinyl derivative, was formed by photodecomposition of fipronil in water and on the soil surface under sunlight. The desulfinyl derivative degraded rapidly in field soils with a half-life of 41–55 days compared with an average half-life of 132 days for fipronil. The half-life of the 'total toxic component' (fipronil and its metabolites) in field soil was 188 days on average.

The use of annual legume green-manure crops as a substitute for summerfallow in the Peace River region

1993 ◽  
Vol 73 (2) ◽  
pp. 243-252 ◽  
Author(s):  
W. A. Rice ◽  
P. E. Olsen ◽  
L. D. Bailey ◽  
V. O. Biederbeck ◽  
A. E. Slinkard
Keyword(s):  
Soil Moisture ◽  
Green Manure ◽  
Field Studies ◽  
Dinitrogen Fixation ◽  
Annual Legumes ◽  
Peace River ◽  
Nitrate N ◽  
River Region ◽  
Green Manure Crops ◽  
Legume Green Manure

Field studies were conducted on a Landry clay-loam soil (Black Solod) to evaluate the effects of green manuring Tangier flatpea (Lathyrus tingitanus 'Tinga'), lentil (Lens culinaris 'Indianhead') and alfalfa (Medicago sativa 'Moapa') on subsequent barley (Hordeum vulgare 'Galt') crops. Each trial consisted of separate legume phases planted in 1984, 1985 and 1986 and barley phases in each of the subsequent years. The flatpea and lentil were incorporated (green manured) in late July or in late August to early September. The alfalfa was incorporated in late August to early September. The 3-yr mean dry matter (DM) yields of lentil and Tangier flatpea varied from 1047 to 2308 kg ha−1, with considerable variability from year to year. Alfalfa, used as an annual legume, produced 812 kg DM ha−1. Dinitrogen fixation by the annual legumes, as assayed by acetylene reduction was 16 kg N ha−1 or less. Soil moisture measurements following the legumes showed 2–3 cm less water in the profile to a depth of 120 cm following alfalfa and late-incorporated Tangier flatpea than following summerfallow and early-incorporated lentil and Tangier flatpea. Ammonium-N levels in the soil were similar following the various legume green-manure treatments. Nitrate-N levels following the legumes were variable, but the levels of nitrate-N in the plots following legume incorporation generally followed the order: fallow > early incorporation > late incorporation. The grain and N yield of barley following early-incorporated lentil and flatpea were equal to or only slightly less than the yield following fallow, suggesting that annual legumes have a good potential as green-manure crops in place of fallow in Black Solod soils of the Peace River region. Key words: Legume plow-down, soil conservation, dinitrogen fixation, soil moisture, nitrate-N

Quackgrass (Agropyron repens) Interference on Corn (Zea mays)

Weed Science ◽  
1984 ◽  
Vol 32 (2) ◽  
pp. 226-234 ◽  
Author(s):  
Frank L. Young ◽  
Donald L. Wyse ◽  
Robert J. Jones
Keyword(s):  
Zea Mays ◽  
Soil Moisture ◽  
Leaf Tissue ◽  
Nutrient Status ◽  
Growing Season ◽  
Field Studies ◽  
Growth And Yield ◽  
Limiting Factors ◽  
Corn Yield ◽  
Agropyron Repens

Field studies were conducted to evaluate the effect of quackgrass [Agropyron repens(L.) Beauv. ♯ AGRRE] density and soil moisture on corn (Zea maysL.) growth and yield. Quackgrass densities ranging from 65 to 390 shoots/m2reduced corn yield 12 to 16%. A quackgrass density of 745 shoots/m2reduced corn yields an average of 37% and significantly reduced corn height, ear length, ear-fill length, kernels/row, rows/ear, and seed weight. In the soil moisture study, quackgrass was shorter than corn throughout the growing season, and analyses of corn leaf tissue indicated that quackgrass did not interfere with the nutrient status of the corn. In 1979, soil moisture was not limiting and corn yields were similar in all treatments regardless of irrigation or the presence of quackgrass. In 1980, soil moisture was limited and irrigation increased the yield of quackgrass-free corn. Irrigation also increased the yield of quackgrass-infested corn to a level similar to irrigated corn. When light and nutrients are not limiting factors, an adequate supply of soil moisture can eliminate the effects of quackgrass interference on the growth, development, and yield of corn.

Field dissipation of S-metolachlor in organic and mineral soils used for sugarcane production in Florida

2019 ◽  
Vol 34 (3) ◽  
pp. 362-370
Author(s):  
Jose V. Fernandez ◽  
D. Calvin Odero ◽  
Gregory E. MacDonald ◽  
Jason A. Ferrell ◽  
Brent A. Sellers ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Linear Trend ◽  
Organic Matter Content ◽  
Field Studies ◽  
Matter Content ◽  
Organic Soils ◽  
Sugarcane Production ◽  
Mineral Soils ◽  
Moisture Conditions

AbstractDissipation of S-metolachlor, a soil-applied herbicide, on organic and mineral soils used for sugarcane production in Florida was evaluated using field studies in 2013 to 2016. S-metolachlor was applied PRE at 2,270 g ha−1 on organic and mineral soils with 75% and 1.6% organic matter, respectively. The rate of dissipation of S-metolachlor was rapid on mineral soils compared with organic soils. Dissipation of S-metolachlor on organic soils followed a negative linear trend resulting in half-lives (DT50) ranging from 50 to 126 d. S-metolachlor loss on organic soils was more rapid under high soil-moisture conditions than in corresponding low soil-moisture conditions. On mineral soils, dissipation of S-metolachlor followed an exponential decline. The DT50 of S-metolachlor on mineral soils ranged from 12 to 24 d. The short persistence of S-metolachlor on mineral soils was likely attributed to low organic matter content with limited adsorptive capability. The results indicate that organic matter content and soil moisture are important for persistence of S-metolachlor on organic and mineral soils used for sugarcane production in Florida.

Evaluation of the magnetite as a magnetic tracer of eroded sediment from ephemeral gullies: conditioning factors of magnetic susceptibility

2020 ◽  
Author(s):  
Elena Zubieta ◽  
Juan Larrasoaña ◽  
Rafael Giménez ◽  
Alaitz Aldaz ◽  
Javier Casalí
Keyword(s):  
Magnetic Susceptibility ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Surface ◽  
Field Capacity ◽  
Field Studies ◽  
Silty Clay ◽  
Magnetic Signal ◽  
Conditioning Factors ◽  
Detection Depth

&lt;p&gt;In gully erosion, the soil detached by the action of the erosive flow can be transported over long distances along the drainage network of the watershed. In this long way, the eroded material can be redistributed and/or deposited on the soil surface, and then eventually buried by eroded material from subsequent erosion events. Likewise, the variability of the soil (i.e., in texture and moisture content) over which this material moves can be considerable. The presence of the eroded material could be detected through magnetic tracers attached/mixed with the eroded soil. In this experiment, the degree to which the magnetic signal of the magnetite is conditioned by (i) the burying tracer depth, (ii) the texture and moisture content of the soil covering the tracer and (iii) the tracer concentration was evaluated.&lt;/p&gt;&lt;p&gt;The study was carried out in the lab in different containers (0.5 x 0.5 x 0.3 m&lt;sup&gt;3&lt;/sup&gt;). Each container was filled with a given soil. In the filling process, a 0.5-cm layer of a soil-magnetite mixture of a certain concentration was interspersed in the soil profile at a certain depth. Overall, 3 different soil:tracer concentrations (1000:1, 200:1, 100:1), 4 tracer burying depths (0 cm, 3 cm, 5 cm and 10 cm from soil surface), and &amp;#160;2 contrasting soils (silty clay and sandy clay loam) were used. In each case, the magnetic susceptibility was measured with a magnetometer (MS3 by Bartington Instruments). Experiments were repeated with different soil moisture contents (from field capacity to dry soil).&lt;/p&gt;&lt;p&gt;If the tracer is located under the soil surface a minimum soil:tracer concentration of 200:1 is required for its correct &amp;#160;detection from the surface using a magnetometer. The intensity of the magnetic signal decreases dramatically with the vertical distance &amp;#160;of the tracer from the soil&amp;#160; surface (burying depth). The maximum detection depth of the tracer magnetic signal is strongly dependent on the natural magnetic susceptibility of the soil which hides the own tracer signal. Variation in soil moisture content does not significantly affect the magnetic signal. For extensive field studies the soil-tracer volume to be handled would be very high. Therefore, it is necessary to explore new tracer application techniques.&lt;/p&gt;

scholarly journals Effect of Preplant Irrigation, Nitrogen Fertilizer Application Timing, and Phosphorus and Potassium Fertilization on Winter Wheat Grain Yield and Water Use Efficiency

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Jacob T. Bushong ◽  
D. Brian Arnall ◽  
William R. Raun
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Grain Yield ◽  
Management Practices ◽  
Fertilizer Application ◽  
N Fertilizer ◽  
Fertilizer Management ◽  
Application Timing ◽  
K Fertilizer ◽  
P Fertilizer

Preplant irrigation can impact fertilizer management in winter wheat. The objective of this study was to evaluate the main and interactive effects of preplant irrigation, N fertilizer application timing, and different N, P, and K fertilizer treatments on grain yield and WUE. Several significant two-way interactions and main effects of all three factors evaluated were observed over four growing seasons for grain yield and WUE. These effects could be described by differences in rainfall and soil moisture content among years. Overall, grain yield and WUE were optimized, if irrigation or adequate soil moisture were available prior to planting. For rain-fed treatments, the timing of N fertilizer application was not as important and could be applied before planting or topdressed without much difference in yield. The application of P fertilizer proved to be beneficial on average years but was not needed in years where above average soil moisture was present. There was no added benefit to applying K fertilizer. In conclusion, N and P fertilizer management practices may need to be altered yearly based on changes in soil moisture from irrigation and/or rainfall.

Methods of rhizobial inoculation and sowing techniques for Trifolium subterraneum L. establishment in a harsh winter environment

1980 ◽  
Vol 31 (4) ◽  
pp. 703 ◽  
Author(s):  
FW Hely ◽  
RJ Hutchings ◽  
M Zorin
Keyword(s):  
Soil Moisture ◽  
Trifolium Subterraneum ◽  
Fertilizer Application ◽  
Low Fertility ◽  
Winter Climate ◽  
Symbiotic Associations ◽  
Commercial Practice ◽  
Spray Inoculation ◽  
Wide Range ◽  
Commercial Inoculant

Placement of Rhizobium trifolii by vertical band spraying of commercial inoculant in suspension with adsorbing clay and fine lime in the soil, above the fertilizer and below the seed of Trifolium subterraneum L., resulted in better seedling nodulation and establishment on low-fertility problem soils over a wide range of soil moisture conditions, when compared with conventional drill-sowing of inoculated, lime-coated seed. Spray inoculation was especially effective in areas where low winter temperature put substantial stress on development of the symbiotic associations. Seed pelleting required favourable soil moisture to permit movement of the bacteria from the pellet to the rhizosphere. The combination of banded spray inoculation with fungicidal seed dusting significantly increased both the numbers and size of nitrogen-fixing nodules on seedlings, and also young plant growth and winter survival. It is concluded that this technique of simultaneous fertilizer application, seed-bed inoculation and sowing of fungicide-dressed seeds greatly increases the options available in commercial practice, particularly in the harsh winter climate of the Southern Tablelands region of New South Wales.

GASEOUS NITROGEN LOSSES FROM CONVENTIONAL AND CHEMICAL SUMMERFALLOW

1985 ◽  
Vol 65 (1) ◽  
pp. 195-203 ◽  
Author(s):  
M. S. AULAKH ◽  
D. A. RENNIE
Keyword(s):  
Soil Moisture ◽  
Field Studies ◽  
Soil Core ◽  
Gaseous Nitrogen ◽  
N Losses ◽  
Factors Affecting ◽  
Major Factors ◽  
Chemical Fallow ◽  
Lower Slope ◽  
Gaseous N Losses

The gaseous losses of N (N2O + N2) measured for 130 days (May-September 1983) from conventional fallow at Yorkton, Oxbow and Weyburn soil sites ranged from 9 to 11, 15 to 31 and 60 to 87 kgN∙ha−1 for upper, middle and lower slope positions, respectively. The corresponding values for chemical fallow were 18–28, 24–51, and 69–98 kgN∙ha−1. In both tillage systems, gaseous N losses increased in the order of upper < middle < lower slope positions and were associated with the variations in soil moisture. The results obtained from additional widely scattered field studies on chernozemic soils further confirmed that the more dense surface soil and relatively higher soil moisture (lower air-filled porosity) were the major factors affecting increased denitrification under chemical fallow. Volumetric soil moisture was the only factor which showed a very highly significant correlation with N2O emmisions. Key words: Acetylene inhibition-soil core technique, chemical fallow, denitrification, nitrification

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