COMPOSTING EFFICIENCY OF INDIGENOUSAND INTRODUCED EARTHWORMS

Transcription

1 COMPOSTING EFFICIENCY OF INDIGENOUSAND INTRODUCED EARTHWORMS tl'ii JUI, T. THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE DEGREE DOCTOR OF PHILOSOPHY FACULTY OF AGRICULTURE KERALA AGRlCULTURAL UNIVERSITY DEPARTMENT OF AGRICULTURAL ENTOMOLOGY COLLEGE OF AGRICULTURE VELLA Y ANI, THlRUV AN AN THAPU RAM 1997

2 CERTIFICATE Certified that tilis thesis entitled "composting efficiency of indigenous and introduced earthworms" is a record of research work done independently by Smt. JIJI. T. ( ) under my guklance and supervision and that it has not previously fonned the basis for the award of any degree. fellowsllip or associatesllip to her. VeliaYaIli Dr. D. Dale C1minJJall, Advisory CollHl1iI/CC Professor of Agr1. EIJIOl1Jology HegioJ Jill Ag1'1. Hesearcl1 Slation Pal/al1wi

3 ABSTRACT Eight species of earthworm belonging to three families were identified from five different soil types of southern Kerala. The identified species were Megascolex cochinensis, M. konkanensis, M. trivandranus, M. trilobatus, Perionyx. sansibaricus, Pheretima heterochaeta (Megascolecidae), Pontoscolex corethrurus (Glossoscolecidae) and Drawida SF. (Moniligastridae). M. cochj.nenses and P. corethrurus were ubiquitous. P. sansibaricus was confined to forest soil and red soil. Forest soil with high water holding capacity, organic carbon content and acidic ph had the highest total count of worms and the highest species diversity. The exotic species Eudrilus eugeniae was more efficient for composting in terms of duration for composting and biomass production. However, the multiplication rate of the indigenous P. sansibaricus was more than that of E. eugemae. In field condition~, when the same weight of worms was used, the time taken for composting was found equal for E. eugeniae and P. sansibaricus. However, the biomass recovery of earthworm was more in E. eugeniae. Both species performed well in the rainy season, compared to hot summer months. The breeding potential, time required for composting and decomposition

4 rate were significantly superior from June to September. There was positive correlation between juvenile count and rainfall and negative correlation with maximum temperature with respect to E. eugeniae. In P. sansibaricus adult and juvenile counts expressed positive correlation with rainfall and humidity and negative correlation with maximum temperature. Space was found to be a determining factor in the growth and multiplication of earthworms. The cocoons of E. eugeniae required 29 1: 1.10 days for hatching. The hatching rate was only :t 1.19 per cent in laboratory condition. The mean number of juveniles hatched/cocoon was 2.88 :t The period required to attain reproductive stage was days. Cocoons of P. sansibaricus was elongate and slender. The time required for hatching of cocoon was 16 1: 0.43 days. The hatching rate was :t per cent in laboratory conditions. The juveniles required :t 0.70 days to become adults. The number of cocoon laid/week was also signific~ntly superior, as compared to E. eugeniae. Vermicompost along with full inorganic fertiliser increased the yield by 21.4 per cent and 19.0 per cent in bittergourd and cowpea, respectively. In cowpea, application of vermicompost without inorganic fertilizer was equally effective as that of the recommended manurial schedule. 4

5 There was significant yield increase when vermicompost was used as a potting mixture in bhindi. However, no significant difference in the biometric characters of plants was observed. Vermicompost along with full inorganic fertiliser increased the yield of bhindi by 15 per cent. The effect of in situ vermiculture (250 worms of p. sansibaricus/plot) was on par with that of Package of Practices Recommendations. Neemcake was found beneficial for supporting growth and multiplication of E. eugeniae. Neem cake recorded 102 per cent increase in juvenile worm production. Neem leaves' and thevetia leaves were equally effective. Mahua cake was not supportive for growth and multiplication. Neem cake was effective in supporting growth and multiplication of P. sansibaricus. Neem cake recorded 52 per cent increase in juvenile worm production. Leaves of neem, clerodendron and glyricidia were equally effective in supporting juvenile worm production as that of the control. Calotropis leaves and mahua cake caused significant reduction in adult, juvenile and cocoon production. In a pot culture study, among the treatments, carbofuran, phorate and quinalphos, quinalphos (0.5 kg and 1.0 kg ai/ha) was found the least toxic to earthworm and there was total survival after an interval of seven days. if

6 The treatments involving earthworms for composting evolved significantly higher CO2 during the period of composting, compared to the control treatment of banana: cowdung mixture without worms. The CO2 evolved by the treatments involving E. eugeniae and P. sansibaricus were on par. Maximum CO2 evolution was observed on the 21st day which was significantly superior to the CO2 evolution estimated at various other intervals. From the 21st day onwards a decline in the CO2 evolution was recorded. The treatment involving earthworm had a significantly higher bacterial, fungal and actinomycetes counts, as against the treatment without worms. The highest fungal count for E. eugeniaewas found on the 28th day. Towards compost maturity the fungal counts were more or less steady; however, a slight increase in the count was observed on the 56th day. There was no definite trend with respect to actinomycetes count during the period of composting. \1\~3'3