PRABHU PRASADINI, PANAND KUMAR, KONIDENA2019-02-052019-02-052018http://krishikosh.egranth.ac.in/handle/1/5810093632D5594A study on “Bioavailability of nutrients in soil on textile sludge application” was undertaken at Department of Environmental Sciences, Advanced Post Graduate Centre, Guntur during 2016-17 to assess the impact of textile sludge on soil. Textile sludge obtained from NSL Textiles Limited, Guntur District, Andhra Pradesh was analyzed with standard procedures for pH, EC, organic carbon, N, P, K and heavy metals. It was found to be neutral in reaction (7.18), with EC of 1.93 dSm-1 and total organic carbon was 13.44 per cent. Total N, P and K contents of textile sludge were 2.6, 0.2 and 2.8 per cent, respectively. Total Zn, Fe, Mn and Cu in textile sludge were 19.45, 468.1, 32.0 and 24.3 ppm, respectively. Total heavy metals viz., lead, nickel, cadmium and chromium were 22.6, 37.6, 4.5 and 106.6 ppm, respectively. Among the heavy metals, Cd content exceeded SEPA limits, whilst Cr content was found to be higher than MSW Rules and others were within permissible limits. An incubation study was conducted using fine textured soil from RARS, Lam to know the bioavailability of nutrients on application of textile sludge with and without microbial consortium at 15, 30 and 45 days of incubation by maintaining soil moisture gravimetrically at maximum water holding capacity (49%). It was laid out in Completely Randomized Design with three replications of ten treatments comprising of three levels of textile sludge (3, 5 and 10 t ha-1) each with three treatments viz., untreated sludge, sludge along with microbial consortium and sludge decomposed with microbial consortium apart from the control i.e., soil alone. Three such sets were maintained to facilitate destructive sampling at 15, 30 and 45 days of incubation. Soil samples were analysed for physicochemical properties, available nutrient status, heavy metals and microbial load (fungi and bacteria) employing standard procedures. The results revealed that the soil pH decreased with incubation time; while EC and organic carbon of soil increased. The major nutrients viz., N, P and K also increased upto 45 days with dose of textile sludge. Among the micronutrients, zinc got released and increased with time (15 to 45 days) of incubation and with increased dose of textile sludge, whereas, Cu values were found to increase from 15 to 30 days of incubation and thereafter, decreased from 30 to 45 days over incubation period. But, Mn content was found to decrease with passage of time and increased with quantum of textile sludge. Availability of toxic heavy metals viz., Pb, Ni, Cd and Cr values showed a decline with period of incubation and Ni, Cd and Cr increased with increasing doses of textile sludge. The level of sludge application, across all the treatments did not have much influence on soil Pb content. DTPA extractable heavy metals, mean values in the soil across the sludge treatments and incubation intervals followed the order: Pb (2.92 ppm) > Cr (0.725 ppm) > Ni (0.4 ppm) > Cd (0.062 ppm). Microbial load like soil fungal populations and bacterial populations were found to increase from initial to 15 days of incubation and thereafter, decreased from 15 days to 45 days, gradually. Whereas microbial load values increased with increasing doses of sludge. The soil properties like pH, EC and organic carbon content were significantly influenced by the imposed treatments. There was a significant influence of application of sludge alone and in combination of with decomposing microbial consortium on available macro and micronutrient content in soil except iron which is non-significant at all the incubation intervals (15, 30 and 45 days). Heavy metals and microbial load (fungi and bacteria population) were also significantly influenced by the application of sludge alone and in combination of with decomposing microbial consortium. The treatment supplied with soil + sludge decomposed with microbial consortium @ 10 t ha-1 (T10) was superior in maintaining the available nutrient status and microbial populations which was followed by the treatments receiving soil + sludge decomposed with microbial consortium @ 5 t ha-1 and 3 t ha-1 and least was recorded in control (soil only). Application of textile sludge showed improvement in soil properties and microbial load in soil. From this, it can be interpreted that application of textile sludge would be helpful in maintaining the soil quality by increasing the microbial load in the soil viz., fungi and bacteria population which are essential for increasing nutrient availability to all crops provided the environmental concerns are duly addressed through composting of textile sludge by promising microbial consortia to keep the heavy metal contents under permissible limits.en-USnullThesis