Applications soil type

Dichloropropene is released into the air and in wastewater during its production and use as a soil fumigant and chemical intermediate. 1,3-Dichloropropene may also leach into groundwater. Considerable variation in the amounts of 1,3-dichloropropene lost by volatilization and degradation can be expected depending on the method of application, soil type, moisture and temperature. It has been detected in low levels in ambient air and drinking-water (United States National Library of Medicine, 1997). 

A recent review of research on phosphorus input to surface waters from agriculture highlights the variability of particulate and dissolved phosphorus contributions to catchments. The input varies with rainfall, fertilizer application rates, the history of the application of the fertilizer, land use, soil type, and between surface and sub-surface water. The balance struck between export of nutrients from the catchment and recipient-water productivity is the primary factor which controls its quality. 

Plant uptake is one of several routes by which an organic contaminant can enter man s food chain. The amount of uptake depends on plant species, concentration, depth of placement, soil type, temperature, moisture, and many other parameters. Translocation of the absorbed material into various plant parts will determine the degree of man s exposure—i.e., whether the material moves to an edible portion of the plant. Past experience with nonpolar chlorinated pesticides suggested optimal uptake conditions are achieved when the chemical is placed in a soil with low adsorptive capacity e.g., a sand), evenly distributed throughout the soil profile, and with oil producing plants. Plant experiments were conducted with one set of parameters that would be optimal for uptake and translocation. The uptake of two dioxins and one phenol (2,4-dichlorophenol (DCP)) from one soil was measured in soybean and oats (7). The application rates were DCP = 0.07 ppm, DCDD 0.10 ppm, and TCDD = 0.06 ppm. The specific activity of the com-... 

O2 availability, water content. Structural - soil type, porosity, clay content, fertility. Agricultural - Fertilizer addition, herbicide pesticide application, tillage, cropping systems etc. 

For studies involving test substance application to soil, there may be a requirement for more soil information than for studies where applications are made to foliage of established crops. The study protocol should describe any specific requirements relative to soil type selection and how to confirm the soil characteristics for the study. Most studies simply require that the soil be identified by its name (e.g., Keystone silt loam) and composition (e.g., percent sand, silt, and clay). This information can typically be acquired from farm records, a soil survey of the local area, or a typical soil analysis by a local soil analysis laboratory. In some instances, a GLP compliant soil analysis must be completed. The study protocol must clearly define what is needed and how it is to be obtained. Unless specified in the protocol, non-GLP sources are adequate to identify the soil and its characteristics. The source of the soil information should be identified in the field trial record. 

The sampling of a suction lysimeter is initiated by applying a vacuum (approximately 40-50 cm of mercury) through the vacuum/pressure line with a hand pump or electric pump. The valve on the sampling line must be closed. A constant vacuum may be maintained on the lysimeter using an electric pump. The time required before collecting a sample from a lysimeter will depend on the method of vacuum application, the moisture content of the soil, and the soil type. 

In more recent applications, several types of ET cover designs also have incorporated synthetic materials, such as geomembranes, which are used to enhance the function of minimizing water into the waste. For example, the Operating Industries Inc. Landfill in California has incorporated a soil layer with a geosynthetic clay liner in the design. The cover system for this site will reduce surface gas emissions, prevent oxygen intrusion and percolation, and provide for erosion control.68... 

Choice of soil type and adsorption constants are less critical than choice of application dates. 

Stored solid manures acts as a source of N20 production/consumption and emission. Covering heaped manure shows reduction in NH3 emissions but has no effect on N20 emission, while other studies showed that both were reduced. The addition of chopped straw reduced N20 emission by 32% from the small scale of cattle manure. [54], Slurry or liquid manure with no cover showed negligible N20 release, while slurry with straw cover might act as a source of emission [55]. N20 emission occurs following manure application to soil [56], Various factors that affect N20 release from soil include (i) type of manure, (ii) soil type, (iii) manure composition, (iv) measurement period, (v) timing of manure application, (vi) amount of manure applied, and (vii) method of application. 

On the basis of this comparison study, at present, it is still difficult to adopt a universal selective sequential dissolution procedure, which may be used everywhere and be suitable for all soils with diversified physical, chemical and mineralogical properties. The application of the SSD procedure must consider individual soil characteristics, such as soil type and properties. The two typical SSD procedures were developed to address soils formed in two climates. The Rehovot procedure was developed to be suitable for the calcareous soils in arid and semi-arid zone soils, whereas the Bonn procedure was created to primarily handle the acid and neutral soils in humid zones. In general, the Bonn procedure appears to be unsuited for calcareous soils in arid and semi-arid zones. The Rehovot procedure has limitations in handling acid and neutral soils, especially forest soils with higher content of organic matter. 

Effect of pH, soil type, and application rate on carbofuran degradation in soils... 

Sensitive terrestrial plants die when soil zinc levels exceed 100 mg/kg or when plant zinc content exceeds 178 mg/kg DW (Table 9.5). The phytotoxic zinc level for barley (Hordeum vulgare) is not known, but zinc content of barley leaf rarely exceeds 100 mg/kg DW (Chang et al. 1983). Uptake of zinc from soils by plants depends on soil type for example, uptake is lower in coarse loamy soils than in fine loamy soils (Chang et al. 1983). Zinc uptake by barley leaf is greater with increasing rate of sludge application, but the relation is not proportional (Table 9.5). 

Table 12.2 Effect of pH, Soil Type, and Application Rate on Carbofuran Degradation in Soils... 

Soil Type pH Initial Application Rate of Carbofuran (mg/kg) Carbofuran Remaining after 3 Weeks (%)... 

Nitrous oxide emissions are generally induced by fertiliser application. Emission strength varies with soil type, temperature and moisture and is substantially crop specific. There is a considerable difference between woody species and cereals. While the Intergovernmental Panel on Climate Change (IPCC) general N20 emission value is set to 1.25% of the nitrogen applied an average of 0.8 to 1.0% could be found from sandy soils. 

For conventional food crops there are several fertilising rate recommendations, based on soil type, intended yield and nutrient content in the harvested crops. The recommended mean application rates in Germany for N range in... 

Walters and Guiseppe-Elle [108] studied the sorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin to soils from aqueous methanol mixtures and evaluated the applicability of the cosolvent theory to such sorption. Sorption kinetics were influenced by the fraction of methanol in the liquid phase and the soil type. Linear equilibrium sorption isotherms were... 

Table 2 is a slightly different view of the applicability of the remediation process. It is broadly divided into organic and inorganic contaminants, and considers the ease of applying a specific technology to a soil type. The categories and assumptions in Table 2 are very broad, and... 

Disulfoton was translocated from a sandy loam soil into asparagus tips. Disulfoton sulfoxide, disulfoton sulfone, disulfoton oxon sulfoxide, and disulfoton oxon sulfone were recovered as metabolites (Szeto and Brown, 1982 Szeto et al., 1983). Disulfoton sulfoxide and disulfoton sulfone were also identified in spinach plants 5.5 months after application (Menzer and Dittman, 1968). Menzer et al. (1970) reported that degradation of disulfoton in soil degraded at a higher rate in the winter months than in the summer months. They postulated that soil type, rather than temperature, had a greater influence on the rate of decomposition of disulfoton. Soils used in the winter and summer months were an Evesboro loamy sand and Chillum silt loam, respectively. The half-life in soil is approximately 5 d (Jury et al., 1987). 

Further studies are necessary to define the field parameters which afford maximum activity of the enzyme (e.g., soil type, amount of moisture, whether or not multiple applications of enzyme are needed). 

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