Dissipation and Phytotoxicity of Dicamba

Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 3-8 ◽  
Author(s):  
R. R. Hahn ◽  
O. C. Burnside ◽  
T. L. Lavy

Dissipation of 2-methoxy-3,6-dichlorobenzoic acid (dicamba) was greater in Sharpsburg silty clay loam soil than in Anselmo sandy loam soil and was faster in the topsoil than in the subsoil. Breakdown increased with increasing soil incubation temperatures. Phytotoxicity of dicamba and 3-amino-2,5-dichlorobenzoic acid (amiben) in aqueous solutions decreased upon exposure to sunlight. Amiben was more susceptible to photodecomposition than was dicamba. Aqueous dicamba solutions exposed to sunlight for 16 days decreased growth of cucumber (Cucumis sativus L.) seedlings, while amiben solutions caused no growth reduction after 2 days' sunlight exposure. Dicamba solutions exposed to 60 C showed increased phytotoxicity while amiben solutions were unaffected. Dicamba was most phytotoxic to corn (Zea mays L.) seedlings at pH 4 and to cucumber seedlings at pH 5. Dicamba solutions were taken up by both shoots and roots of corn and cucumber seedlings; however, root uptake resulted in greater growth reductions.

2019 ◽  
Vol 65 (No. 2) ◽  
pp. 97-103
Author(s):  
Marek Kołodziejczyk ◽  
Andrzej Oleksy ◽  
Bogdan Kulig ◽  
Andrzej Lepiarczyk

The cultivation of plants under the covers made of synthetic polymers brings many benefits, however, it is associated with the need to utilize or recycle these materials after the period of their use. Such problems are not caused by the covers made of natural polymers. The aim of the study carried out in the years 2013–2014 was to determine an effect of covers made of biopolymers and synthetic polymers on thermal conditions and potato yield. Field study was carried out under sandy loam and silty clay loam soils conditions. The temperature of silty clay loam soil under the covers was on average by 2.9°C higher than in the unprotected area, whereas sandy loam soil had the temperature higher by 2.5°C under biodegradable foil and by 2.7°C under standard foil. Temperature increase under non-woven fabrics was lower than under foils. The highest increase in marketable tuber yield after 40 days from emergence and in full maturity of potato plants was found after at application of standard non-woven fabric P17 (7.2 and 7.4 t/ha, respectively) and the lowest, i.e., 3.0 and 3.4 t/ha, respectively, under biodegradable foil. Cover type had no effect on the number of tubers formed on the first harvest date, whereas a significantly higher number of tubers was recorded in the full maturity of plants in the year characterized by a longer growing period of potato under non-woven P17 on sandy loam soil, and under biodegradable foil on silty clay loam soil conditions. A significant influence of cover on the average tuber weight on the first harvest date was found only on sandy loam soil under non-woven fabrics in 2013, as compared to full maturity of plants under biodegradable covers on sandy loam soil in 2013 and on silty clay loam soil under all covers in 2014.


Weed Science ◽  
1993 ◽  
Vol 41 (2) ◽  
pp. 246-250 ◽  
Author(s):  
Eleni Kotoula-Syka ◽  
Ilias G. Eleftherohorinos ◽  
Athanasios A. Gagianas ◽  
Achilleas G. Sficas

A pot bioassay, based on root growth of pregerminated corn, was used to evaluate factors influencing field persistence of chlorsulfuron, metsulfuron, triasulfuron, and tribenuron, which were applied preemergence at 0, 10, 20, and 40 g ai ha−1to wheat grown in three soils that differed in texture (sandy loam, sandy clay loam, and silty clay loam) and pH (7.9, 4.7, and 7.6). Residual activity and leaching of all herbicides in all soils increased with increasing rate of application, with the exception of tribenuron which showed practically no residual activity and leaching in sandy clay loam soil. Sunflower sown 4 mo after tribenuron application in all soils was not injured by any rate used but was significantly affected by the other herbicides. Lentil and sugarbeet also were affected by all herbicides in all soils. These three crops sown 8 mo after herbicide application were not affected by any herbicide used in the sandy clay loam soil but were injured by chlorsulfuron, triasulfuron, and metsulfuron in the sandy loam soil. Only lentil and sugarbeet were injured by chlorsulfuron in the silty clay loam soil.


Author(s):  
Mohammed Aajmi Salman ◽  
Jawad A. Kamal Al-Shibani

Beneficial microorganisms play a key role in the availability of ions minerals in the soil and use Randomized Complete Block Desing ( R.C.B.D ). The objective of this paper to the study effect of the of biofertilizer and miniral treatments on availability of NPK for crop corn zea mays L.Two types of biofertilizer are Bacterial Bacillus subtilis and Fungal Trichoderma harianum. Three levels of potassium fertilizer are (2.9533, 0.4000 and 2.9533). A field experiment in fall season of 2018 Has been conducted in silty clay loam soil. The experimental Results indicated that Bacillus and Trichoderma inoculation separately or together Have made a significant effect to increase in the availability of N P K in the soil compare to other treatments. The grain yield is where (2.9533, 0.4000 and 2.9533) of bacterial and fungal bio-fertilizer and potassium fertilizers respectively as compared to the control.


2008 ◽  
Vol 88 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Hafida Zaher ◽  
Jean Caron

The slaking process after rapid wetting is a key factor controlling soil structural stability in dry soil, and an understanding of the relative importance of the different mechanisms involved in slaking may help in the design of management strategies aimed at maintaining a stable surface soil structure. Slaking has been linked to, among other factors, rapid pressure build-up in aggregate, and previous work has emphasized the role of organic matter to hamper that pressure build-up, possibly due to hydrophobicity, reducing rapid water entry within aggregates and hence the build-up. This study emphasizes this latter aspect linked to slaking. The evolution of the intra-aggregate pressure, the matter lost by slaking and the expelled air after rapid wetting of two soils of different textures (clay loam soil and silty-clay loam soil) amended with different types of paper sludge were studied. Hydrophobicity effects were also studied using a tensio-active solution. The results of these experiments showed that when aggregates were submitted to sudden wetting, those treated with paper sludge had an improved resistance to the destructive action of rapid wetting. The lower pressures measured in the aggregates from the amended soils and having less slaking resulted most likely from slow water entry and reduced swelling. Detailed investigation on the link between hydrophobicity and water entry revealed that the true hydrophobic effect (modification of contact angle) was non-existent for the silty-clay loam and minor for the clay loam. This study, rather, suggests that changes in the water potential at the wetting front following organic matter addition and aggregate immersion most likely depend on pore occlusion and on changes in pore surface roughness. Key words: Aggregate stability, organic matter, slaking, pressure, swelling, wettability


Weed Science ◽  
1974 ◽  
Vol 22 (6) ◽  
pp. 600-603 ◽  
Author(s):  
W. L. Barrentine

The competitive effects of common cocklebur (Xanthium pensylvanicumWallr.) on soybeans[Glycine max(L.) Merr. ‘Lee 68′] were studied on Dundee silty clay loam soil from 1970 to 1972. Full-season competition by common cocklebur at 3,300, 6,600, 13,000, and 26,000 plants/ha reduced the 2-year average soybean seed yields 10, 28, 43, and 52%, respectively. Competition from common cocklebur at 100,000 plants/ha for 4, 6, 8, 10, 12, and 16 weeks after soybean emergence reduced soybean seed yields 10, 36, 40, 60, 80, and 80%, respectively. A reduction in soybean stand occurred after 12 or more weeks competition, and an increase in soybean plant height occurred after 10 or more weeks competition. When common cockleburs were removed during the first 4 weeks after soybean emergence, no further removal was required to obtain maximum soybean yield. Bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] at 1.1 to 2.2 kg/ha applied over-the-top of common cockleburs and soybeans was as effective as hand removal in terminating competition provided common cocklebur plants were not flowering.


2016 ◽  
Vol 11 ◽  
Author(s):  
Angela Libutti ◽  
Massimo Mucci ◽  
Matteo Francavilla ◽  
Massimo Monteleone

Biochar incorporation into agricultural soils has been proposed as a strategy to decrease nutrient leaching. The present study was designed to assess the effect of biochar on nitrate retention in a silty clay loam soil. Biochar obtained from the pyrogasification of fir wood chips was applied to soil and tested in a range of laboratory sorption experiments. Four soil treatments were considered: soil only (control), soil with 2, 4 and 8% of biochar by mass. The Freundlich sorption isotherm model was used to fit the adsorbed amount of nitrate in the soil-biochar mixtures. The model performed very well in interpreting the experimental data according to a general linear regression (ANCOVA) statistical approach. Nitrate retention in the soil-biochar mixtures was always higher than control, regardless the NO<sub>3</sub><sup>-</sup> concentration in the range of 0-400 mg l<sup>-1</sup>. Different sorption capacities and intensities were detected depending on the biochar application rate. The highest adsorption capacity was observed in the soils added with 2 and 4% of biochar, respectively. From the results obtained is possible to infer that nitrate retention is higher at lower biochar addition rate to soil (2 and 4%) and at lower nitrate concentration in the soil water solution. These preliminary laboratory results suggest that biochar addition to a typical Mediterranean agricultural soil could be an effective management option to mitigate nitrate leaching.


1986 ◽  
Vol 50 (6) ◽  
pp. 1494-1499 ◽  
Author(s):  
R. S. Thomas ◽  
S. Dakessian ◽  
R. N. Ames ◽  
M. S. Brown ◽  
G. J. Bethlenfalvay

Soil Research ◽  
2017 ◽  
Vol 55 (4) ◽  
pp. 389 ◽  
Author(s):  
Iman Ahmadi

One of the most important soil degradation agents in agriculture is compaction. To rehabilitate compacted fields, farmers usually use subsoilers to break compacted layers. Moreover, the required draft force of a subsoiler dictates the amount of energy needed to operate it. Therefore, measurement, calculation or prediction of the draft force of this machine is vital for designing an efficient subsoiler. In the present study, an analytical model was developed to calculate the subsoiler draft force. To verify the model developed herein, model outputs regarding the draft force of a subsoiler were compared with corresponding results from the American Society of Agricultural Engineers (ASAE) standard, as well as the results of literature studies. Moreover, the output of the model was compared with the measured draft force of subsoiling a silty clay loam soil. Furthermore, the results obtained regarding the quantitative effect of model inputs on the draft force of a subsoiler were checked from the viewpoint of compatibility with the expected trends or observed results in other studies. The data obtained from the developed model were compatible with those of the ASAE standard. Moreover, the draft force of a single-shank subsoiler was almost 10 kN, which is approximately 14% higher than the result obtained by the model (8.73 kN). Therefore, the model developed herein can be used to calculate the subsoiler draft force with reasonable accuracy. Of the machine parameters, subsoiler wingspan had an adverse effect on the specific draft of this machine. Moreover, for the range of working depths between 30 and 50cm, the minimum values of specific draft took place.


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