Plants residues

Od condensed from the released volatdes from the second stage is filtered and catalyticady hydrotreated at high pressure to produce a synthetic cmde od. Medium heat-content gas produced after the removal of H2S and CO2 is suitable as clean fuel. The pyrolysis gas produced, however, is insufficient to provide the fuel requirement for the total plant. Residual char, 50—60% of the feed coal, has a heating value and sulfur content about the same as feed coal, and its utilisation may thus largely dictate process utdity. 

Nitrate is one of the facts of life. It is essential for the growth of many plant species, including most of those we eat, but it becomes a problem if it gets into water in which it is not wanted. It is perceived mainly as a chemical fertilizer used by farmers, but much of the nitrate found in soil is produced by the microbes that break down plant residues and other nitrogen-containing residues in the soil. There is no difference between nitrate from fertilizer and that produced by microbes, but, whatever its origin, this rather commonplace chemical entity has now become a major environmental problem and is also treated as a health hazard. 

The gas and liquid are separated in the cold separator, which is a three-phase separator. Water and glycol come off the bottom, hydrocarbon liquids are routed to the distillation tower and gas flows out the top. If it is desirable to recover ethane, this still is called a de-methanizer. If only propane and heavier components are to be recovered it is called a de-etha-nizer. Tiie gas is called plant residue and is the outlet gas from the plant. 

On plant surfaces, as in soils, numerous studies have demonstrated that endosulfan is oxidized to endosulfan sulfate. Initial residues of endosulfan on treated vegetables generally range from 1 to 100 mg/kg. However, residue levels typically decrease to less than 20% of initial levels within 1 week after treatment (NRCC 1975). Residues of endosulfan isomers are generally negligible after 2-3 weeks the a-isomer is much less persistent than the P-isomer. In most plant residue studies, endosulfan sulfate residue levels tend to increase relative to the parent isomers and other metabolites and appear to be very persistent (Coleman and Dolinger 1982). 

Input rates of organic C into the soil system are hard to quantify, particularly for natural ecosystems and to a lesser extent for agricultural ecosystems. Whereas quantity and quality of carbon inputs via litter fall and plant residues after harvest might be directly measurable, inputs via roots and rhizodeposition are more difficult to assess. 

S0rensen et al. (44) hypothesized that finer plant residues (i.e., upon grinding) may have better contact between substrate and decomposer organisms within the soil matrix and would decompose less extensively than coarser (i.e., intact. 

There are indications that the variety of C substrates in the rhizosphere soil is basically too wide to be significantly affected by changes in quality of plant residues from the previous crop. For example, legumes as preceding crop were shown to increase significantly microbial diversity in the bulk soil, as estimated by Biolog assay, whereas in the rhizosphere soil this effect of legumes could not be detected (145). 

N. Watkins, and D. Barraclough, Gross rates of N mineralization associated with the decomposition of plant residues. Soil Biol. Biochem. 2S 5169 (1996). 

E. S. Jensen, Mineralization-immobilization of nitrogen in. soil amended with low C N ratio plant residues with different particle sizes. Soil Biol. Biochem. 26 519 (1994). 

Reconstitute the dry plant residue from Section 6.2.1 in 50 mL of hexane saturated with acetonitrile and transfer the flask contents to a 250-mL separatory funnel. Rinse the round-bottom flask with 50 mL of acetonitrile saturated with hexane and add this rinse to the hexane in the separatory funnel. Partition the residue from the hexane into the acetonitrile. Drain the acetonitrile into the 500-mL flask from the dichloromethane partition step (Section 6.2.1). Re-extract the remaining hexane phase with an additional 50 mL of acetonitrile saturated with hexane. Combine the acetonitrile fraction with the acetonitrile from the first partition. Concentrate the combined acetonitrile fractions to dryness in a rotary evaporator at <40 °C. Dissolve the dry residue in 1 mL of ethyl acetate and dilute the sample with 2mL of hexane. Sonicate the sample for... 

Chemicals with allelopathic potential are present in virtually all plant tissues, including leaves, stems, roots, rhizomes, flowers, fruits, and seeds. Whether these compounds are released from the plant to the environment in quantities sufficient to elicit a response, remains the critical question in field studies of allelopathy. Allelochemics may be released from plant tissues in a variety of ways, including volatilization, root exudation, leaching, and decomposition of the plant residues. 

Leachates of Donor Residue. Use of leachates of donor plant residue results In much less total material being put Into the growth medium of the receiver. Thus, this Is a more refined manner In which to test for allelopathic Inhibition of mineral absorption. 

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