| The wastewater disposed by textile industries is causing majorhazards to the environment and drinking water due to presence of a largenumber of contaminants like acids, bases, toxic organic, inorganic,therefore the industrial wastewater needs to be dealt with reasonablybefore discharge. Rice straw is unique relative to other cereal straws inbeing low in lignin and high in silica. Unlike other cereal straws tallervarieties of rice straws tend to be leafy while the leaves are less digestedthan stems. This may contribute to higher straw value with rice yield.There is genetic variation in straw quality but has not been exploited andtends to be smaller than environmental variation. Effort in plant breedinghas been to develop short varieties with higher grain yield. Thisdevelopment has reduced straw quantity but not nutritive value. Therelationship between plant genetics and silica metabolism is virtuallyuninvestigated, although reviews from plant physiology indicate it is amajor factor. Silica and lignin in that order are the primary limitingfactors in rice straw quality. Silicon is a nutriment element which hasbeen overlooked largely because of its assumed inertness, but alsobecause of its geochemical abundance that so greatly exceeds itsmetabolic use by plants and animals. Silicon is involved in several majorroles in rice: carbohydrate synthesis, grain yield, phonetic synthesis andplant cell wall protection. These vectors interact with each other toeliminate statistical association of silica and lignin with straw digestibilitywhen varieties are compared. Yield of grain is highly related to silicacontent of straw, which reelects soil availability. There are no detailedstudies on rice straw lignin. Most papers reporting lignin contents in ricestraw have used acid-detergent lignin by either the sulfuric acid orpermanganate versions. There are undoubtedly soluble phonetics in ricestraw that need investigation. The effects of ammonia and urea on silica isto crack the solicited cubicula layer. Silica is not dissolved by thesereagents in contrast to the action of sodium hydroxide.Treatments on rice straw follow those applied to other ignitedmaterials. In order of frequency of reports, urea followed by ammonia with comparatively fewer papers on sodium hydroxide, steam andpressure treatments or exploded by pressure release, and only one or twopapers on acid treatments and white rot fungi. There are reports on animalsupplementation and a few growth studies with young animals. Fieldsurveys in India and the southeast Asian countries only report the use ofurea, although it appears less efficient than ammonia. Farmer acceptanceis related to their perceptions on costs, labor, equipment, health, safety, i.e.the exposure to ammonia vapor, economic and other social factors. Thevarious papers reporting treatments have used animal digestion trials;variety of in Sacco, in vitro digestions with rumen organisms or cellulose,some in combination with pepsin digestion or neutral-detergent extraction.Gas production from in vitro rumen fermentation has also been used.Results are expressed mainly on dry matter basis and fewer reports onorganic matter. Results are difficult to compare and standardization ofprocedures is badly needed. However, most treatments with ammonia andurea show some increase in digestibility and intake where measured invivo trials. In vitro and in Sacco evaluations tend to overestimateimprovement in digestibility. |
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