CHANDRASEKHAR RAO, PSITA RAMA LAKSHMI, CH2016-06-092016-06-092011http://krishikosh.egranth.ac.in/handle/1/67118The present investigation entitled “Vermicomposting for effective waste management and its evaluation under INM in rice-pulse cropping system” was carried out at Regional Agricultural Research Station, Anakapalle during 2009 and 2010, to study the nature and properties of humic substances and to monitor the changes in nutrient status and enzyme activities during composting and vermicomposting of different organic residues i.e sugarcane trash, weeds, vegetable market waste and paddy straw. After preparation of different composts, field experiments were conducted in rice-pulse cropping system for evaluation of different vermicomposts. The results revealed that the duration of vermicomposting varied from 55 to 60 days for various organic residues under study, while it took almost 110 days for composting. Total organic carbon and C/N ratio decreased with the passage of time during vermicomposting and composting in all the organic residues, however the percent decrease was more in vermicomposting than composting in a particular period of time. Total nitrogen content of different vermicomposts and composts increased during composting process, however more increase was observed in vermicomposting than composting. In both the composts, highest and lowest total nitrogen was recorded in vegetable market waste and paddy straw, respectively. In both the composts paddy straw recorded the highest C/N ratio while vegetable market waste exhibited lowest C/N ratio. At the end of vermicomposting i.e at 60 days the C/N ratio was reduced to 21.60, 12.70, 11.34 and 21.57 in cane trash, weeds, vegetable market waste and paddy straw, respectively. Whereas in composting the C/N ratio at maturity (110 days) was 24.71, 13.76, 12.73 and 24.89 in cane trash, weeds, vegetable market waste and paddy straw, respectively. The humic and fulvic production increased with incubation in both the composting methods and in all the treatments. At the end of vermicomposting significant increase in humic acid content (10.85 %) was recorded in vegetable market waste than cane trash and paddy straw vermicompost. A well known index for humification is the HA/FA ratio, in both the composts paddy straw compost recorded minimum ratio and maximum ratio was recorded in vegetable market waste compost. In both the composting methods the total nitrogen content of humic acid was found to increase with the progress of the composting, while reverse trend was noticed with C/N ratio. Comparatively the total nitrogen content of humic acid was more in vermicomposts than composts. Functional group analysis in different vermicomposts showed that, as incubation proceeded there was an increase in contents of total acidity, carboxyl groups and phenolic OH groups. At the end of composting higher total acidity and carboxylic groups of humic acid was recorded in vegetable market waste, while phenolic groups were higher in composts and vermicomposts obtained from paddy straw. In both the composting methods the enzyme activity (urease, phosphatase, dehydrogenase and cellulase) decreased with increasing the composting period in all the organic residues. However highest urease, phosphatase and dehydrogenase activity was recorded in vegetable market waste compost, while lowest in paddy straw compost. Whereas cellulase activity was high in paddy straw and low in vegetable market waste and weed composts. Almost 50 to 55 % increase in dehydrogenase activity in vermicomposting than composting and 48 and 26 % increase of acid and alkaline phosphatase activity in vermicomposting than composting. It was observed that total NPK and micronutrient content in both the composts were significantly higher in vegetable market waste compost with narrow C/N ratio and the reverse trend was followed in cane trash and paddy straw. Reduction in pH was observed in all matured composts compared to their initial values. Evaluation of different vermicomposts under rice-pulse cropping system revealed that the organic carbon content, macro and micronutrient status was increased with the incorporation of different vermicomposts than 100 % chemical fertilizer treatment, however all the treatments were significantly superior over control. Among different treatments 75 % RDFN+ vegetable market waste compost @ 2.5 t ha-1 performed better in all aspects and it was on par with 75 % RDFN + weed vermicompost @ 2.5 t ha-1 and 50 % RDFN+ vegetable market waste compost @ 2.5 t ha-1. Among different treatments, humic substances were significantly higher in T7 (75 % RDFN + vegetable market waste @ 2.5 tha-1). The humic acid and fulvic acid obtained from the selected treatment (T7) showed that the potentiometric titration curves were sigmoidal in nature suggesting weak acidic character of these fractions. The conductometric titration curves of humic fractions indicated that they behave as weak acids which can be due to slow increase in conductance with the addition of NaOH to neutralize its acidity. Urease, phosphatase, dehydrogenase and cellulase activities at different growth stages of the crops gradually increased over the age of the crop and attained higher activity at flowering and gradually decreased at harvest. Significantly higher nutrient uptake was recorded in all the INM treatment than 100 % chemical fertilizer treatment, however it was superior than absolute control. At flowering and at harvest higher nitrogen uptake was recorded in the treatment which received 75 % RDFN+VMWVC @ 2.5 tha-1 to kharif rice over 100 % recommended dose of chemical fertilizer. Among different INM treatments, 75 % RDFN in combination with different vermicomposts (T5 to T8) recorded significantly high grain and straw yields compared to 50 % RDFN in combination with different vermicomposts i.e T 1 to T4. However, higher grain yield (5.85 t ha-1) was recorded in 75 % RDFN+ VMW VC @ 2.5 t ha-1 and it was on par with 50 % Prathista organic manures + 50 % chemical fertilizers (5.80 t ha-1), 75 % RDFN+ WVC @ 2.5 tha-1 (5.60 t ha-1) and 100 % Prathista organic manures (5.60 t ha-1). Cumulative and residual effects of Integrated Nutrient Management practices of kharif rice on rabi greengram revealed that, all the cumulative treatments showed higher values of soil nutrient status, humic and fulvic acid content, enzyme activities and nutrient uptake by green gram than their corresponding residual treatments in both the years. Further it was also observed that in both cumulative and residual effects the treatment which received 75 % RDFN + VMW VC @ 2.5 tha-1 during preceding rice crop performed better in all aspects. All the cumulative effects recorded higher seed yields than their respective treatments for residual effects. The over all effect of chemical fertilizers were found to be lower than integrated use of different vermicomposts with respect to soil nutrient status, enzyme activity, humic substances, growth and yield of both rice and greengram during both the years. The treatment with 100 % Prathista Organic manures (T11) is highest profitable among all the treatments (BCR = 2.92) and it was closely followed by T7: 75 % RDFN + VMWVC @ 2.5 t ha-1 (BCR = 2.81) and least profitable is absolute control i.e T10 (BCR=1.65). In rabi greengram, both cumulative and residual treatments are profitable. Highest profitable treatment in both cumulative and residual effects was T7 (3.85 and 3.76) followed by T 12 ( 3.76 and 3.65), T6 (3.73 and 3.64) and least profitable is absolute control i.e T10 (2.08 and 1.64).enacidity, vermicomposting, composting, rice, organic acids, organic fertilizers, enzymes, wastes, crop residues, nitrogenThesis