Efficacy of downy brome herbicides as influenced by soil properties

1994 ◽  
Vol 74 (1) ◽  
pp. 177-183 ◽  
Author(s):  
R. E. Blackshaw ◽  
J. R. Moyer ◽  
G. C. Kozub
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Bromus Tectorum ◽  
Edaphic Factors ◽  
Downy Brome ◽  
Winter Cereals ◽  
Highly Correlated

Controlled environment experiments were conducted to determine the effect of various edaphic factors on the efficacy of metribuzin, BAY SMY 1500, cinmethylin, and napropamide to control downy brome (Bromus tectorum L.). Experiment 1 determined the effects of soil organic matter, pH and texture and experiment 2 determined the effect of soil water contents ranging from −0.03 to −1.5 MPa on herbicide efficacy on downy brome. Metribuzin, BAY SMY 1500, cinmethylin, and napropamide efficacy on downy brome was highly correlated with soil organic matter and soil water content. Phytotoxicity of these herbicides was decreased up to two- to threefold as organic matter increased and soil water content decreased. Metribuzin and BAY SMY 1500 efficacy on downy brome increased as soil pH increased. Cinmethylin was more efficacious in sandy soils. This information may aid in determination of precise herbicide rates for various soil types to allow growers to achieve consistent control of downy brome without injuring winter cereals. Key words: Edaphic factors, cinmethylin, BAY SMY 1500, metribuzin, napropamide, Bromus tectorum L.

A numerical approach for understanding the main parameters and processes influencing the soil organic matter decay in wildfire events

2020 ◽  
Author(s):  
Sebastián A. Aedo ◽  
Carlos A. Bonilla
Keyword(s):  
Thermal Conductivity ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
High Temperatures ◽  
Pore Radius ◽  
Radiative Energy ◽  
Soil Response

<p>High temperatures reached at topsoil during wildfires can induce changes in physical, chemical, and biological soil properties. In the end, these changes are related to the loss of soil organic matter (SOM) and control the post-fire soil management decision. Therefore, the objectives of this study were: (1) to develop a numerical model to predict the SOM decay during wildfires, and (2) to study which are the main parameters that control the soil response. The model couples the energy balance for soil heating, and the species conservation for water and SOM using high temperature-induced vaporization and combustion kinetics. Fluid flow was neglected; however, radiative energy conducted through pores was included as a function of the volumetric pore radius. The soil thermal evolution showed values of r<sup>2</sup>>0.92 when the radiative term in the thermal conductivity was neglected, and r<sup>2</sup>>0.98 when the volumetric pore radius was adjusted. The results showed that the main parameters that control the soil response were soil texture, soil water content, volumetric pore radius, and oxygen availability. Also, soil response depends on the surface temperature and exposure time. Soil water content enhances the thermal properties and determines the amount of heat consumed during vaporization because of the high enthalpy of this endothermic reaction. On the other hand, neglecting oxygen flux leads to restricted oxidation, limiting the SOM decay. In terms of texture, silty soils showed the lower soil response, clay and loamy soils an intermediate response, and sandy soils had a higher response. Also, the volumetric pore radius enhances the soil thermal conductivity at high temperatures, leading to higher temperatures near the soil surface. These results suggest that the normalized SOM decay does not depend on the initial SOM content.</p>

Adsorption and Diffusion of Dinitroaniline Herbicides in Soils

Weed Science ◽  
1979 ◽  
Vol 27 (4) ◽  
pp. 450-455 ◽  
Author(s):  
G. L. Jacques ◽  
R. G. Harvey
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
The Other ◽  
Silt Loam ◽  
Relative Mobility ◽  
Water Saturated ◽  
And Diffusion ◽  
Dinitroaniline Herbicides

Adsorption of benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline], oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), profluralin [N-(cyclopropylmethyl)-α,α,α-tri-fluoro-2,6-dinitro-N-propyl-p-toluidine], and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) was studied in 10 Wisconsin soils. Ratios of the quantity of each herbicide adsorbed and quantities remaining in the soil solution at equilibrium (Kd value) on a Piano silt loam (Typic Argiudoll fine-silty, mixed, mesic) remained relatively constant over a range of concentrations. Herbicide adsorption by the soils was related more closely to soil organic matter than to the other soil chemical and physical properties. Diffusion of the herbicides in Piano silt loam was affected by soil water. Diffusion of trifluralin, profluralin and benefin decreased as soil water increased. Diffusion of dinitramine and fluchloralin did not change significantly with change in water content. Diffusion of oryzalin increased at the highest soil water content. None of the herbicides moved more than 10 mm in the soil during a 17-day period. In unsaturated Piano silt loam, relative mobility of the herbicides was trifluralin ≥benefin>profluralin>fluchloralin>dinitramine≥oryzalin. Oryzalin reached highest mobility in water-saturated soil.

Effects of Ecological Projects on Grassland Soil Physicochemical Properties in Three-River Headwater

2013 ◽  
Vol 807-809 ◽  
pp. 843-847
Author(s):  
Xu Dong Zhao ◽  
De Gang Zhang ◽  
Li Na Shi ◽  
Yong Shun Yang
Keyword(s):  
Organic Matter ◽  
Physicochemical Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Available Phosphorus ◽  
Soil Physicochemical Properties ◽  
Total N ◽  
Effective Measure ◽  
Artificial Grassland

The depth variations of soil physicochemical properties in the degraded native grasslands and the artificially restored grasslands were studied in the Three-river headwater areas of Qinghai-Tibetan plateau, China. The results showed: (1) With the increase of the gradient of restoration years, soil water content, total chemical properties, total potassium, phosphorus, available phosphorus and potassium were increased thereafter in the artificial grasslands. (2) With the increase of grassland degradation gradient, soil water content was gradually reduced, and the total N, K, the organic matter didnt gradually reduced also. (3) Both restoration years and degradation degree didnt influence the nutrient distribution in soil. (4) The organic matter, total N and K of degraded grassland were increased by artificial grassland construction. Therefore, artificial grassland construction canbe used as an effective measure of ecological projects in the Three-river headwater area.

Distribution of carbon and nutrients and fluxes of mineral nitrogen after clear-felling a Pinusradiata plantation

1990 ◽  
Vol 20 (9) ◽  
pp. 1490-1497 ◽  
Author(s):  
P. J. Smethurst ◽  
E. K. S. Nambiar
Keyword(s):  
Organic Matter ◽  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
N Mineralization ◽  
Soil Depth ◽  
Mineral N ◽  
Southeastern Australia ◽  
Nutrients Fluxes

The effects of clear-felling and slash removal on the distribution of organic matter and nutrients, fluxes of mineral N, and soil water and temperature were studied in a 37-year-old Pinusradiata D. Don plantation, on a sandy Podzol in southeastern Australia. Slash, litter, and the top 30 cm of soil combined contained 1957 kg N•ha−1, of which slash and litter contained 12 and 25%, respectively. Therefore, loss of slash and litter due to burning or other intensive site preparation practices would substantially reduce the N capital at the site. During the first 18 months after clear-felling, soil water content in the clear-felled area was up to 50% higher than in the uncut plantation, but there were only minor differences in soil temperature. Slash removal decreased the water content of litter, but had little effect on the water content or temperature of the soil. In the uncut plantation, N mineralized in litter and soil was completely taken up by the trees. Following clear-felling, rates of N mineralization increased in litter after 4 months, and in soil after 12 months, but changes were less pronounced with slash removal. After clear-felling, increased mineralization and the absence of trees (no uptake) led to increased concentrations of mineral N in both litter and soil, 64–76% of which was leached below the 30 cm soil depth prior to replanting. Despite leaching, concentrations of mineral N after clear-felling remained higher than those in the uncut plantation for at least 3 years.

scholarly journals Evaluation of Improved Model to Accurately Monitor Soil Water Content

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3441
Author(s):  
Jingyu Ji ◽  
Junzeng Xu ◽  
Yixin Xiao ◽  
Yajun Luan
Keyword(s):  
Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Irrigation Management ◽  
Clay Fraction ◽  
Organic Matter Content ◽  
Matter Content ◽  
Improved Model

The accurate monitoring of soil water content during the growth of crops is of great importance to improve agricultural water use efficiency. The Campbell model is one of the most widely used models for monitoring soil moisture content from soil thermal conductivities in farmland, which always needs to be calibrated due to the lack of adequate original data and the limitation of measurement methods. To precisely predict the water content of complex soils using the Campbell model, this model was evaluated by investigating several factors, including soil texture, bulk density and organic matter. The comparison of the R2 and the reduced Chi-Sqr values, which were calculated by Origin, was conducted to calibrate the Campbell model calculated. In addition, combining factors of parameters, a new parameter named m related to soil texture and the organic matter was firstly introduced and the original fitting parameter, E, was improved to an expression related to clay fraction and the organic matter content in the improved model. The soil data collected from both the laboratory and the previous literature were used to assess the revised model. The results show that most of the R2 values of the improved model are >0.95, and the reduced Chi-Sqr values are <0.01, which presents a better matching performance compared to the original. It is concluded that the improved model provides more accurate monitoring of soil water content for water irrigation management.

scholarly journals Long-Term Soil Water Content and Exchangeable Ca Interact to Stabilize Organic Matter

2020 ◽  
Author(s):  
Itamar Shabtai ◽  
Srabani Das ◽  
Thiago Inagaki ◽  
Johannes Lehmann
Keyword(s):  
Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Exchangeable Ca
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