VERMICOMPOSTING FOR EFFECTIVE WASTE MANAGEMENT AND ITS EVALUATION UNDER INM IN RICE-PULSE CROPPING SYSTEM
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Date
2011
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ACHARYA N.G.RANGA AGRICULTURAL UNIVERISTY
Abstract
The 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).
Description
Keywords
acidity, vermicomposting, composting, rice, organic acids, organic fertilizers, enzymes, wastes, crop residues, nitrogen