Efficacy of Selected Herbicides as Influenced by Soil Properties

1990 ◽  
Vol 4 (2) ◽  
pp. 279-283 ◽  
Author(s):  
Michael R. Blumhorst ◽  
Jerome B. Weber ◽  
Len R. Swain

Field experiments were conducted on six loam and sandy loam soils to study the influence of various soil parameters on atrazine, cyanazine, alachlor, metolachlor, and pendimethalin efficacy. Herbicidal activity was highly correlated to the soil organic content. Humic matter content was equally or better correlated (r = 0.70 to 0.91) with herbicide bioactivity than was organic matter content (r = 0.66 to 0.84). Regression equations were determined which allow herbicide rate recommendations for 80% weed control to be calculated based on soil humic matter or organic matter levels.

1987 ◽  
Vol 1 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Jerome B. Weber ◽  
M. Ray Tucker ◽  
Robert A. Isaac

Percent soil organic matter content, as determined by standard chromic acid oxidations, was highly (r = 0.89) correlated with soil humic matter content, as determined by NaOH/DTPA (diethylenetriaminepenta-acetic acid)/alcohol extraction of 201 U.S. soils. Humic matter content of the soils was equally or better correlated (r = 0.89 to 0.97) with herbicide bioactivity, as measured in field experiments, than was percent organic matter content (r = 0.87 to 0.92). Regression equations provided allow herbicide rate recommendations for 80% weed control to be calculated based on soil humic matter or soil organic matter levels.


2020 ◽  
Vol 12 (1) ◽  
pp. 143-153
Author(s):  
Risikat N. AHMED ◽  
Sesan M. SOBA ◽  
Mercy O. BAMIGBOYE ◽  
Kamoldeen A. AJIJOLAKEWU

The present research aimed at screening various soils within Ilorin metropolis for antibiotic producing actinomycetes. The objectives of the study were to determine physiochemical parameters of soils, the occurrence of actinomycetes in soils, antibacterial potentials and identity of isolates. Soil parameters such as pH, temperature, moisture, organic matter and soil type were evaluated following standard procedures. Selective isolation to determine the occurrence of actinomycetes was performed by soil dilution using pour plate technique on starch casein agar. Preliminary antibacterial screening against 10 clinical test bacteria was performed using cross streak method. All isolates were initially identified based on morphological and biochemical characteristics, while the most bioactive isolates were further identified by molecular means. The soils were alkaline, with temperatures between 29 °C and 31 °C, moisture was in range of 0.72 ± 0.07c and 6.62 ± 0.42b. Highest organic matter content was 32.13 ± 0.20a with soil types mostly loamy and sandy loam. Ten actinomycetes (SM1 - SM10) were isolated, with the most frequently occurring isolate being SM3 and SM5 (16.7%). SM5 was the most active, inhibiting 9 out of 10 tests, with the highest inhibition against Staphylococcus aureus 25923 (24 mm ± 0.15a). All isolates were identified as Streptomyces by morphology and biochemical tests. Based on nucleotide similarity searches and phylogeny, two bioactive Streptomycetes were suggested as novel strains and thus named as Streptomyces bottropensis UIL RNA (SM5) and S. flavoviridis UIL RNA(SM7), which may serve as promising sources of antibiotics. Actinomycetes from Ilorin metropolis demonstrated broad spectrum of antibacterial activity against clinical test bacteria.


1976 ◽  
Vol 56 (3) ◽  
pp. 129-138 ◽  
Author(s):  
A. J. MACLEAN

The Cd concentration in 10 plant species grown in a neutral surface soil (0.65 ppm Cd) varied from 0.18 ppm in potato tubers to 0.99 ppm in soybean roots on a dry matter basis. Addition of 5 ppm Cd increased the concentrations in the plants markedly and they were particularly high in lettuce (10.36 ppm) and tobacco leaves (11.57 ppm). Cd concentrations tended to be lower in the edible portion (seed, fruit, tubers) than in other plant parts. Added Cd affected yields in only a few instances. But in another experiment, Cd added at a rate of 5 ppm to five soils decreased the yield of lettuce in most instances. In a comparison of results for two similarly managed sandy loam soils, nearly neutral in reaction but differing in organic matter content (2.17 vs. 15.95% organic C), the concentration of Cd was lower in lettuce grown in the soil with the higher amount of organic matter. The Cd content of the lettuce was reduced by liming some of the acid soils. Addition of Cd increased the concentration of Zn in the plants appreciably, but added Zn did not affect Cd uptake. In an incubation experiment comprising five soils, DTPA (diethylenetriamine-pentaacetic acid) extractable Cd decreased with liming of three Cd-treated acid soil samples. In comparisons of two sandy loam soils and of surface and subsoil layers of a sand, extractable Cd increased with higher amounts of soil organic matter.


1998 ◽  
Vol 49 (5) ◽  
pp. 775 ◽  
Author(s):  
Ajit K. Sarmah ◽  
Rai S. Kookana ◽  
A. M. Alston

The sulfonylurea herbicides comprise a group of compounds designed to control broad-leaved weeds and some grasses in a variety of crops. The herbicides have become popular because of their low application rates (10-40 g/ha), low mammalian toxicity, and unprecedented herbicidal activity. We present a review of the fate and behaviour of these herbicides in soils with particular reference to alkaline soils of Australia. The review shows that the low application rates of sulfonylurea herbicides continue to present an analytical challenge, although in recent years a number of new methods capable of detecting them at very low concentrations have been developed. A range of analytical methods is available, including high performance liquid chromatography, gas chromatography, immunoassay, and bioassay. However, analytical sensitivity required to detect trace levels of these herbicides continues to pose problems in routine detection of herbicide residues in soils. The review reveals that there are no reports of studies of the behaviour of sulfonylureas in soils with pH >8·2. This is of particular significance to Australian conditions because a number of Australian soils are even more alkaline, and the pH(water) in subsoils can be as high as 10· 2. Sorption of sulfonylureas is pH-dependent and has a strong negative correlation with pH. At pH >8·0 sorption is very low. In acid soils, however, sorption of chlorsulfuron, metsulfuron-methyl, and triasulfuron is strongly influenced by the soil temperature, clay content, and, particularly, organic matter content. The principal modes of degradation of the herbicides are acid hydrolysis and microbial degradation with the latter being the only major pathway in alkaline soils. Hydrolysis of the sulfonylureas is more rapid under acidic conditions (pH 4{7), and the data suggest that hydrolysis is likely to be very slow in alkaline soils. Data from other countries suggest that the half-life of chlorsulfur on increases exponentially with pH, and that it is also influenced by variations in the temperature and water content of the soil. Being acidic in nature, the herbicide molecules become anionic at high pH and can move to a considerable depth in the soil profile by leaching. Movement of the sulfonylureas in soil is largely influenced by organic matter content and soil pH and the reviewed data show that sulfonylureas have substantial leaching potential in the sandy alkaline soils of Australia. This is likely to result in increased persistence in alkaline subsoils lacking in organic matter and biological activity. Computer models to predict the persistence and movement of the sulfonylureas are available; however, additional input parameters are required to predict accurately the behaviour of specific herbicides in alkaline soils under Australian conditions. Since new herbicides with chemistry similar to existing sulfonylureas are increasingly likely to be available for use, there is a need to develop comprehensive understanding of their fate, behaviour, and impact on Australian cropping and ecological systems.


2019 ◽  
Vol 78 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Beata Bosiacka ◽  
Helena Więcław ◽  
Paweł Marciniuk ◽  
Marek Podlasiński

Abstract The vegetation of protected salt meadows along the Baltic coast is fairly well known; however, dandelions have been so far treated as a collective species. The aim of our study was to examine the microspecies diversity of the genus Taraxacum in Polish salt and brackish coastal meadows and to analyse soil property preferences of the dandelion microspecies identified. In addition, we analysed the relations between soil properties and vegetation patterns in dandelion-supporting coastal meadows (by canonical correspondence analysis). The salt and brackish meadows along the Polish Baltic coast we visited were found to support a total of 27 dandelion microspecies representing 5 sections. Analysis of vegetation patterns showed all the soil parameters (C:N ratio, organic matter content, pH, concentration of Mg, P, K, electrolytic conductivity of the saturated soil extract ECe) to explain 32.07% of the total variance in the species data. The maximum abundance of most dandelion microspecies was associated with the highest soil fertility, moderate pH values and organic matter content, and with the lowest magnesium content and soil salinity. The exceptions were T. latissimum, T. stenoglossum, T. pulchrifolium and T. lucidum the occur-rence of which was related to the lowest soil fertility and the highest salinity. In addition, several microspecies (T. leptodon, T. gentile, T. haematicum, T. fusciflorum and T. balticum) were observed at moderate C:N ratios and ECe. Four other microspecies (T. infestum, T. cordatum, T. hamatum, T. sertatum) occurred at the lowest pH and organic matter content. The information obtained increases the still insufficient body of knowledge on ecological spectra of individual dandelion microspecies, hence their potential indicator properties.


Weed Science ◽  
1979 ◽  
Vol 27 (4) ◽  
pp. 456-459 ◽  
Author(s):  
A. Loh ◽  
S. J. Parka ◽  
R. Albritton ◽  
C. C. Lin

The rate of herbicide required to reduce growth of grain sorghum (Sorghum vulgare, Per. ‘Pioneer 8417′) by 50% (GR50) and soil adsorption coefficients (Ka) were determined for the experimental herbicide, fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone}, in 14 soils. A linear correlation analysis was conducted between GR50values and the chemical and physical properties and fluridone absorption coefficient (Ka) for 14 soils. The GR50values were significantly correlated to soil organic matter and Ka. A stepwise regression analysis suggests that Kaor organic matter content can be used to predict the rate of fluridone application required for herbicidal activity.


2020 ◽  
Author(s):  
Belén Oliva-Urcia ◽  
Ana Moreno ◽  
Blas Valero-Garcés

<p>Paleoenvironmental reconstructions from three mountaineous lakes located in northern Iberia are compared and completed with classical magnetic analyses in order to detect the influence of different processes on the record and preservation of magnetic properties. The lakes are located in the Cantabrian Mountains, Enol Lake, and in the Pyrenees, the Marboré Lake and Basa de la Mora Lake and share a similar composition of their catchment areas, dominated by limestones. They present other different characteristics, such as in the organic matter content, being Enol the one with the highest organic carbon values. Redox indicator (Mn/Fe) is higher and more variable in Basa de la Mora Lake, whereas in Enol and Marboré Lakes steadily increases towards the top of the sequences. New and revisited results from sedimentary cores unravel the significance of the magnetic changes respect to the geochemical and sedimentological variations found in the geological record.</p><p>The magnetic mineralogy present after analyses done in discrete samples (less than 500 mg) is magnetite in all samples, due to a sharp decrease at 120 K (Verwey crystallographic transition) and 580ºC (Curie temperature of magnetite) in the thermomagnetic curves performed in the MPMS and the Curie balance respectively. No indication of neither pyrrhotite (phase transition at 35 K) nor siderite is observed. The high temperature thermomagnetic analyses show the presence and creation of magnetite during heating, see an increasing of induced magnetization forming a broad peak above 450ºC in the heating curve. In addition, a subtle change in the induced magnetization is observed at around 300ºC. All analyses related with coercivity indicate the predominance of low coercitive minerals (“soft”) as magnetite is.</p><p>The combination of geochemical, sedimentological and magnetic proxies suggest that in Enol Lake the magnetic signal may be dominated by the formation of new minerals in relation to redox processes favored by the higher presence of organic matter (6%organic content), whereas in Marboré Lake, the increase of the magnetic signal toward the top of the sequence seems related to the oxic environment and the preservation of magnetite, since this lake is ultra-oligotrophic. In Basa de la Mora Lake, the source rock seems to play a role in the magnetic signal of the sequence.</p><p>These results indicate that diagenesis and changes in the redox conditions alter the concentration of magnetic minerals during the Late Pleistocene and Holocene and underlines their value as environmental and paleoclimate archives.</p><p><strong>Acknowledgements</strong></p><p>Funding for this research was provided by the Spanish Inter-Ministry Commission of Science and Technology through MEDLANT (CGL2016-76215-R) and DINAMO 3 (Ref CGL2015-69160-R) projects and by the European Commission (EFA056/15 REPLIM). The Institute for Rock Magnetism (IRM), the Instrumentation and Facilities program of the National Science Foundation of the Earth Science Division and the University of Minnesota are acknowledged for supporting visits and the free use of the facilities at the IRM, together with the both easy-going and expert guidance from the IRM staff.</p>


1982 ◽  
Vol 62 (1) ◽  
pp. 165-175 ◽  
Author(s):  
C. R. DE KIMPE ◽  
M. BERNIER-CARDOU ◽  
P. JOLICOEUR

Twenty-one topsoils, with texture varying from sandy loam to clay and organic matter content ranging from 1.6 to 11.9%, were submitted to compaction and settling at different moisture contents where dry bulk density was determined. Under compaction, the density curve went through a maximum while a minimum was observed in the case of settling. Optimum moisture contents corresponding to these two characteristic densities were almost the same. The most important physical properties affecting soil behavior under compaction and settling were found to be water retention properties at low matric potential which themselves depended primarily on organic matter content. Samples submitted to compaction had saturated hydraulic conductivities less than 1 cm/h, while after settling, Ksat measurements ranged from 0.8 to 234 cm/h. Organic matter played an important role in reducing the effects of compaction, and moisture content alone was not sufficient to predict the best conditions for workability in the fields.


Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 880
Author(s):  
Mohammad Reza Chaichi ◽  
Marcus Turcios ◽  
Mina Rostamza

Non-ionic surfactants have been well researched as a tool to ameliorate water repellent conditions. However, few studies have evaluated the risks and benefits of non-ionic surfactant applications in wettable soil. The objective of this study was to evaluate the effects of a surfactant in modifying the wetting pattern in soils of different textures and organic matter contents. The experimental treatments consisted of (1) four different soil textures including sandy, sandy loam, sandy clay loam and silt loam, (2) four different organic matter contents (0.2, 0.7, 1.2 and 1.7% by weight), and (3) irrigation water treatments with or without surfactant (IrrigAid Gold). The experiment was carried out in Plexiglas boxes with one drip emitter under the soil surface. The results demonstrated the superiority of surfactant application on increasing water distribution in the soil profile for all soil textural classes. Silt loam texture had the highest side wetted area and wetting depth 45min after the initiation of irrigation. Upward capillary water movement and top wetted area significantly decreased in the surfactant treatment across all soil textures except in sandy soil. As organic matter content increased, top wetted area decreased. These findings clarified the potential ability of surfactant in increasing water infiltration in non-repellent soil in an in vitro system.


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