Soil drainage

The MTG regulations require that granular soil drainage materials must5... 

To calculate the required flow rate, Q, in granular soil drainage designs based on MTG values ... 

U.S. EPA specifies that the minimum detection time for the leachate entering the LDS of an LDCR system is <24 h. Response time calculations are based on velocity in the geonet and/or granular soil drainage layer. Darcy s law is used to calculate flow velocity in the geonet, and a true velocity must be used for granular soil. 

Berrow M.L., Burridge J.C., Reith J.W.S. Soil drainage conditions and related plant trace element contents. J Sci Food Agric 1983 34 53-54. 

Ecosystem functioning Free metal ion concentration in soil solution re-calculated to total dissolved metal concentration in soil drainage water (in view of effects on soil microorganisms, plants and invertebrates) 1.7-20.4 1.3-3.2 ... 

Critical Loads of Heavy Metals Depending on ERA Endpoints The ecosystem characteristics of case study plots in various natural forests of the European part of Russia are shown in Table 4. Critical loads in an occasion of human health and ecotoxicological effects on biota (endpoints) have been accounted. Corresponding critical limits of HM concentration in soil drainage waters are presented in Table 1. 

Mendelssohn, I. A., and Seneca, E. (1980). The influence of soil drainage on the growth of salt marsh cordgrass, Spartina alternijlora, in North Carolina. Estuar. Coastal Mar. Sci. 11, 27—40. 

Destroy infected plants or leaves and thin remaining plants to increase air movement. Prevent problems by working lots of compost into the soil before planting, and plant lettuce in raised beds to improve soil drainage. Spray plants with compost tea every 2 weeks to help suppress diseases. 

Tree stunted and bears yellow leaves. Causes Crown rot blackline. If the trunk near the soil line is diseolored or oozing sap. suspect crown rot, a disease caused by too much water and poor soil drainage. Improved drainage may help. If you find small holes or cracks at the graft union, remove some bark around the area and look for a black line. Blackline virus infects English walnuts grafted onto J. hindsii rootstocks. There is no cure. 

Know the general conditions of occurrence and stability of the major clay mineral groups, including the roles played by parent mineralogy, temperature, precipitation rate, soil drainage, and soil maturity in clay occurrence. 

Fig. 6. Mean concentrations of total dissolved solids in different types of waters, in relation with soil drainage intensity.

For the sesquioxides, the problem could be different. Throughfall and runoff waters, with near-neutral pH, are undersaturated in SiO2, with respect to quartz (concentration below 10 mol/1, i.e. 6 mg/1 see Tardy, 1969), but soil drainage and spring waters are saturated or oversaturated (see Table II). 

Stream water is soil drainage plus surface runoff. Natural drainage waters contain relatively low concentrations of the essential ions. This slow and steady input from drainage waters supports what is generally regarded as a natural and desirable aquatic population in streams and lakes. 

Alkali and alkaline earth cations, halides, sulfate, and silica ions tend to remain in solution, rather than precipitate as secondary minerals. Despite the soil s ability to retain ions, these ions under normal soil drainage conditions eventually reach the sea. The K, Mg, and Si move more slowly than do Na, Ca, halides, and sulfate. Under arid to semiarid conditions, much Ca precipitates as lime CaC03 and some as gypsum CaSC>4 2H20. 

Another example of weathering reversal is salt accumulation due to impeded soil drainage or seawater inundation. Weathering under these conditions reverses in the sense that the secondary minerals formed are chemically similar to igneous and sedimentary rock minerals and are unstable under well-drained, oxidative conditions. The chemistry of soil development deals with the degradation of parent minerals and the formation of secondary minerals over a wide range of chemical conditions. 

Super Wet [WA. Qeary] Ntmionic wetting ent for penetration to compacted soil and thatch, imnnoting soil drainage and pesticide tv fertilizer rffi-ciency. 

In 1993 cropped land accounted for 19 per cent of the total land area of developing countries of the region. This indicates that significant inroads have already been made into land with low production potential, which include unirrigated areas with arid and semi-arid climates, or unreliable rainfall, areas with steep slopes or poor soil drainage or a combination of these features. Such areas tend to be ones where environmental degradation is most severe. 

Super Wet [W.A. Qeary] Nonicmic wetting agent for penetratkm to compacted soil and thatch, promoting soil drainage and pesticide or fertilizer efficiency. 

A number of factors can affect the availability of molybdenum (Mo) to crops. The most important ones include the nature of the parent rock, soil pH, the organic matter in the soil, drainage, interactions with other nutrients, and plant species, plant part, and stage of plant growth at sampling. This chapter attempts to review the information available on the soil and plant factors that affect Mo uptake by plants in different parts of the world. 

Figure 11.14 Section through the wall of a corrugated F VC pipe, of diameter 150 mm, for soil drainage.

Kirkham, D., Zeeuw de, J.W. (1952). Field measurements for tests of soil drainage theory. 

A high water level is defined as when the water level is 300 mm beneath the formation level and is consistent with effective sub-soil drainage a low water level is when the water level is 1 m below the formation level. Good construction conditions result in subgrades never getting wetter than their equilibrium moisture contents beneath the finished road. A thick pavement is 1200 mm deep, including a 650 mm capping layer, and is typical of motorway construction a thin pavement is 300 mm deep. For pavements of intermediate thickness founded on plastic soils, an equilibrium value of GBR may be interpolated (Powell et al. 1984). 

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