Farm soils

The following is a general farming classification based on some of the main soil types - clays, sands, loams, calcareons soils, silts, peats and peaty soils. 

These soils have a high proportion of clay and silty material - ustrally over 60%, at least half of which is pttre clay. These so-called heavy soils include the clay, silty clay and sandy clay textirres. It is the clay content which is mainly responsible for their specific characteristics. Particles of clay have very important properties  

Grouping or flocculation of the particles is very important in making clay soils easy to work. Clay particles combined with calcitrm (hme) will flocculate easily, whereas those combined with sodium will not. The adhesive properties of clay are very beneficial to the soil structure when the groups of particles ate small (like cmmbs). Defiocculation can occur when clay soils are Hooded with sea water or worked when wet. If the latter occurs they become puddled and if the weather then becomes dry the clay dries into hard lumps or clods. Frost action, and 

These soils are mainly composed of sand (greater than 70%) with very little clay (less than 15%) or silt. The soil texture is either a sand or loamy sand. Because these soils contain very little clay or organic matter they tend to be very weakly structured. They are very easy to work. No natural restructuring takes place on these soils so any compaction has to be removed using cultivations. As sand is inert the cation exchange capacity of these soils is very low. Because of the large particle size of sand these soils contain a large number of macropores which tend to contain air rather than water. 

Sandy soils are very prone to both wind and water erosion and run-off on slopes, and wind erosion in the spring can destroy a young crop. Various methods are available to reduce the risk of erosion including planting nurse crops, applying organic manures and cultivations. 

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J. Swinnen, J. A. van Veen, and R. Merckx, Carbon fluxes in the rhizosphere of winter wheat and spring barley with conventional vs integrated farming. Soil Biol. Biochem. 27 811 (1995). 

When available land space is insufficient for land farming, soil treatment can be carried out in piles or pits. Typical biopile and biopit constructions are presented in Figure 14.8 and Figure 14.9, respectively. When the soil has relatively low permeability, the pile can be constructed with sequential lifts of soil, approximately 60 cm in thickness, separated by permeable sand layers. These layers are connected with a vacuum pump or blower that is used to produce airflow though the soil pile. Water and nutrients are sprinkled on the top of the pile. 

Gamon M, Saez E, Gil J et al (2003) Direct and indirect exogenous contamination by pesticides of rice-farming soils in a Mediterranean wetland. Arch Environ Contam Toxicol 44 141-151... 

Farm soils, United States mean vs. too acidic to 30 vs. <3 5... 

Keywords Comparison Functional diversity Molecular tool Organic farming Soil processes... 

Organically farmed soils have significantly higher biological activity than those conventionally farmed. 

Petersen, S. O., Debosz, K., Schonning, P., Christensen, B. T. and S. Elmholt (1997). Phospholid fatty acid profiles and C availability in wet-stable maero-aggregates from conventionally and organieally farmed soils. Geoderma 78 181-196. 

The single largest use of ammonia is its direct apphcation as fertdizer, and in the manufacture of ammonium fertilizers that have increased world food production dramatically. Such ammonia-based fertilizers are now the primary source of nitrogen in farm soils. Ammonia also is used in the manufacture of nitric acid, synthetic fibers, plastics, explosives and miscellaneous ammonium salts. Liquid ammonia is used as a solvent for many inorganic reactions in non-aqueous phase. Other apphcations include synthesis of amines and imines as a fluid for supercritical fluid extraction and chromatography and as a reference standard in i N-NMR. 

Shepherd, M.A., Harrison, R. and Webb, J. 2002. Managing soil organic matter - implications for soil structure on organic farms. Soil Use and Management 18 284-292. 

Areas of peaks tentatively identified as B8-531, B8-1414 + B8-1945, B8-806/809 and B8-2229 (peaks 5-8 Fig. 2) were normalized to peak B8-1414/1945 = 1 (Peak 6), and the resulting profiles are shown in Fig. 7 for Lake Superior air and water, air sampled above farm soil in the southern United States [30], and a toxaphene standard. The profiles in Lake Superior surface water and air appear more similar to the toxaphene that has outgassed from farm soil than to the technical toxaphene standard, but there are differences in the profiles that cannotbe explained. Chlorobornanes B8-531 and B8-806/809 weresignifi-... 

Teixeira, VS, Franco EP. 1986. Root uptake of exogenous radium-226 by three edible vegetables grown in farm soils from the vicinity of the first Brazilian uranium mine and mill [Abstract], Chem Environ Proc Int Conf 837-842. (CA 110 7068b)... 

Kaul, S. and Sumbali, G. (1997). Keratinolysis by poultry farm soil fungi. Myco-pathologia 139,137-140. 

Conventional farming does not eschew the basics of organic farming. Soil structure and dynamics, fertility, drainage, and rotation - all are considered. But when there is an economically viable short cut that frees the farmer from the need to work in harmony with the laws of nature, the conventional farmer will take it. The conventional farmer does not consider the macrocosm, does not take into account the impact on the outside world of actions on the microcosm of the farm. 

The Soil Association Organic Marketing Company (1999) Standards for Organic Food and Farming. Soil Association Organic Marketing Company, Bristol. 

Westbom, R., Hussein, A., Megersa, N., Retta, N., Mathiasson, L., Bjorklund, E. Assessment of organochlorine pesticide pollution in Upper Awash Ethiopian state farm soils using selective pressurized liquid extraction. Chemosphere, 72 1181-1187 (2008). 

There has been an increasing interest in the determination of selenium at trace levels in a wide variety of matrices. Selenium determinations of environmental samples have become quite important. Large-scale poisoning of water fowl has occurred in several watershed areas of central California. Selenium is washed or leached into these areas, helped through the widespread irrigation of selenium-containing farm soil. 

Land farming has been used extensively to treat soils contaminated with petroleum hydrocarbons, pentachlorophenol (PCP), and polycyclic aromatic hydrocarbons (PAHs), and potentially could be used to treat low to medium concentrations of explosives as well. In land farming, soils are excavated to treatment plots and periodically rototilled to mix in nutrients,... 

The fate of CPs in biosolids that are applied to farmland, a common practice in Europe and a growing practice in North America, has not been thoroughly investigated. Nicholls et al. [18] did not detect SCCPs/MCCPs in farm soils amended with sludges containing mg/kg concentrations of CPs. However, worms living in these same soils did contain low mg/kg wet wt. levels of CPs. 

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