Crops determination

Table 7—Plant-to-soil concentration factors of 144Ce in crops determined from...

The nature of the crop determines how the mushrooms should be picked. Flushes with mush-.i rbom in varying stages of development are more difficult to harvest. This is especially true if the (promordia formation period was interrupted by fluctuations in the environment. One example is a henomenon common to Psilocybe cubensis culture in mason jars. Mushrooms sometimes form... 

Quality and quantity of any crop determine its price in the market place. Although quantity is readily measurable, quantity in units of weight or volume, quality is a less readily measurable attribute. Quality pertains to the characteristics of the commodity and varies somewhat according to the perceptions of different individuals. Nevertheless, grades and standards can and have been established for numerous products to describe their quality characteristics. Many current grades and standards including those for peanut crops, are not as useful as they could be, because they do not accurately de.scribe the essential quality characteristics of the product concerned ( ). 

If the filtrate is of value, it should be transferred to another vessel immediately the crystals have been drained. Frequently, the mother liquor may be con centra ted (suitable precautions being, of course, taken if it is inflammable), and a further crop of crystals obtained. Occasionally, yet another crop may be produced. The crops thus isolated are generally less pure than the first crystals which separate, and should be recrystaUised from fresh solvent the purity is checked by a melting point determination. 

To determine the feasibiUty of, or need for, fertilization requires knowing (/) which of the required elements, if any, are deficient in the soil (2) what chemical forms of the deficient elements are assimilable by the plants and thus suitable as fertilizers (5) what quantity of fertilizer material is required to meet the needs of the crop and (4) whether the crop yield increase resulting from fertilizer appHcation would warrant the cost of the fertilizer production and appHcation. 

A food processing establishment in a facility processes crops grown at the facility in a separate establishment. The facility could base the value of the products of each establishment on the total production value of each establishment. Alternatively, the facility could determine the value of the crops grown at the agricultural establishment. Then, to calculate the contribution of the food processing establishment, the facility would subtract the crop value from the total value of the product shipped from the processing establishment. 

A typical CBA involves a description of the expected decrease in emissions and a model of the impact pathways, such as an estimation of the average damage per emission unit. It involves a valuation of damage units such as loss of 1 kg crop, one person admission to hospital due to respiratory infections, etc. As an example, a part of a result table from a study in determining external environmental costs fot the production of electricity from coaU is shown in Table 15.5. 

The effect of water salinity on crop growth is largely of osmotic nature. Osmotic pressure is related to the total salt concentration rather than the concentration of individual ionic elements. Salinity is commonly expressed as the electric conductivity of the irrigation water. Salt concentration can be determined by Total Dissolved Solids (TDS) or by Electrical Conductivity (EC). Under a water scarcity condition, salt tolerance of agricultural crops will be the primordial parameter when the quality of irrigation water is implicated for the integrated water resources management [10]. 

Koen JG, Huber JF. 1970. A rapid method for residue analysis by column liquid chromatography with polarographic detection Application to the determination of parathion and methyl parathion on crops. Anal Chim Acta 51 303-307. 

Rusibamayila CS, Ak habuhaya JL, Lodenius M. 1998. Determination of pesticide residues is some major food crops of Northern Tanzania. J Environ Sci Health B 33(4) 399-409. 

The o-dichlorobenzene extracts were combined and analyzed by GLC. Four peaks were observed under standard GLC conditions in the 10 to 15 min retention time range which is characteristic of hexachloro-dibenzo-p-dioxins (sample 1 in Table IV). The mixture was fractionally sublimed (120° to 175°G/1 mm). The major crop was harvested at 175 °G and recrystallized from anisole. Analysis of this material by GLG indicated that two isomeric hexachlorodibenzo-p-dioxins were present (sample 2). Overall yield (1.5 grams) of the product was 1-3% at 99+% purity, as determined by GLG and mass spectrometry. 

Association of pigment accumulation with DNA features can inform systematics and applied breeding in crop plants. For carotenoid content among crop plants, maize and tomato are best studied by this technique. Because there is interest in accumulation of various intermediate products in the pathway as well as end products, QTLs were developed for genetic determinates that are not independent of each other. Some QTLs affect multiple pigment contents. 

The determination of lead in blood is the most widespread clinical use of ASV The technique is attractive because it is rapid, simple and reproducible A recent advance is to couple ASV to flow injection analysis in order to automate the process so that smaller samples and shorter analysis time can be achieved Lead is also routinely determined in bonemeal meant for human consumption by ASV Both lead and cadmium are determined in agricultural crops by ASV... 

Iodine is incorporated in thyroid proteins to form thyroxin and 3-I-thyroxine, both hormones essential for life. They are determined by immunochemical methods. Deficiency of I may lead to crop disease. 

The pathogenicity of DRB to crop plants has been shown to be host-specific (35) and thus is conceivably linked to root exudation. Alstrom (169) found that the pathogenicity of two isolates of Pseudomonas was determined by the major components of the broth culture in which they were applied to bean seedlings. Both isolates were pathogenic to bean seedlings when the broth contained sucrose and peptone or sucrose and yea.st extract. When the broth contained sucrose alone, one isolate was pathogenic and the other was not. Neither isolate was pathogenic when the broth contained yea.st extract or peptone alone (169). 

Recently, pulse labeling has frequently been applied to determine the fate of carbon in crops such as barley and wheat and the losses from roots and subsequent microbial transformations. In general, the results indicate that 15-25% of the net " C assimilation is transferred to the roots and that there are seasonal differences in the distribution of assimilated carbon. Meharg and Killham (25) measured the C distribution in perennial ryegrass (L perenne). At 8 days after the pulse with... 

J. H. Qian and J. W. Doran, Available carbon relea.sed from crop rcxtts during growth as determined by carbon-13 natural abundance. Soil Sci. Soc. Am. J. 60 828 (1996). 

The limit of determination [or limit of quantitation (LOQ)] is defined in Directive 96/46/EC as the lowest concentration tested at which an acceptable mean recovery (normally 70-110%) and acceptable relative standard deviation (normally <20%) are obtained. The specific requirements for LOQ in crops, food, feed, soil, drinking and surface water, air, body fluids, and tissues are described in Section 4. Because the abbreviation LOD usually means limit of detection rather than limit of determination, the authors prefer not to use this abbreviation here in order to avoid confusion, and LOQ is used throughout. According to Directive 96/46/EC no data with regard to the limit of detection must be given. 

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