PhD

The experiment entitled “Characterization and evaluation of on-farm
liquid organic manures on soil health and crop nutrition” was undertaken at
College of Agriculture, Vellayani during 2014-2017.The study was envisaged
to characterize the on-farm liquid organic manures viz., cow urine,
panchagavya, fish amino acid, vermiwash and jeevamrutha, to monitor the
nutrient release pattern under laboratory conditions
and to evaluate the
efficacy of soil and foliar applications of these liquid manures on soil health
and crop nutrition using bhindi as test crop.
The study consisted of
three parts. The first part comprised the
preparation and characterization of above said on-farm liquid organic
manures. These manures were prepared as per standard procedures and
characterization study was conducted to determine the physical, chemical,
biological and biochemical properties.
Physical properties viz., colour and odour of different on-farm liquid
organic manures were recorded. Among the liquid organic manures studied,
fish amino acid and panchagavya showed acidic pH and other three liquid
organic manures viz., cow urine, jeevamrutha and vermiwash recorded neutral
pH. Regarding EC, jeevamrutha recorded the lowest value (1.53 dSm-1).The
highest OC content (39.96%) was recorded by fish amino acid followed by
panchagavya. Among the major nutrients, the highest N content (0.45%) was
found in panchgavya followed by fish amino acid. The highest P content was
recorded by FAA (0.41%). Maximum K content (0.17%) was recorded in cow
urine followed by panchagavya, vermiwash and jeevamrutha. S content of all
the liquid organic manures were higher compared to Ca and Mg content. The
highest contents of Ca, Mg and S were recorded by fish amino acid. The Fe
content (39.92mg L-1) was highest in jeevamrutha and the lowest in fish
amino acid. Cow urine was found to be rich in Mn (0.400 mg L-1) and Cu
(21.21 mg L-1).The maximum zinc content (2.00 mg L-1), IAA (6.00μg ml-1)
and GA (35.00μg ml-1) were found in fish amino acid. Panchagavya was rich
in cytokinin (2.82 mg L-1) whereas, ascorbic acid content (37.50 mg 100g-1)
was the highest in vermiwash. Fish amino acid was registered the highest
enzyme activities, except for dehydrogenase activity which was found to be
maximum in cow urine (371.27 μg of TPF g -1soil 24 h-1) followed by fish
amino acid (336.98 μg of TPF g -1soil 24 h-1). The maximum population of
bacteria was observed in vermiwash and fungal population was presented in
all liquid organic manures except cow urine. The highest azotobacter
population was observed in fish amino acid. K solubilizers were found to be
the highest in vermiwash whereas E.coli, P solubilizers, azospirillum and
Pseudomonas sp. were not detected in any of the above liquid organic
manures.
The second part of the experiment was laboratory incubation study to
monitor the nutrient release pattern from soil treated with the on-farm liquid
organic manures for a period of two months. The study consisted of 6
treatments which included soil alone and soil treated with 10 per cent dilution
of all the liquid organic manures separately and all the treatments were
maintained at 60 per cent moisture level. In general increased pH and EC
values were observed in all the treatments received diluted liquid organic
manures compared to control. Regarding the release of major, secondary and
micronutrients, there was significant difference in available nutrient contents
between treatments during the periods of incubation. Regarding the release
of N and P during incubation study, soil along with FAA 10 per cent recorded
the highest release pattern whereas soil along with cow urine 10 per cent
recorded the highest K release throughout the incubation period. There was
increased release of Ca in the treatments received liquid organic manures. The
highest Mg release throughout the incubation period was registered by the
treatment received cow urine 10 per cent. Available iron content was higher
in T5 (soil 5 kg + jeevamrutha 10 %) compared to other treatments. A
significant difference was found among treatments with respect to available
Zn content. Initially (0th day of incubation), all the treatments were recorded
higher values compared to values recorded on 7th ,15th ,30th , 45th and 60th
days of incubation. There was increasing trends in the Cu content of soil from
0th day of incubation to 60th day of incubation except in the case of T3 (soil
5 kg + FAA 10 %). Treatment T1 (soil without treatments) recorded the
lowest values for all nutrients throughout the incubation period.
The third part of the experiment was to evaluate the efficacy of soil and
foliar applications of on-farm liquid organic manures in a
pot culture
experiment using bhindi as test crop. The treatments included were 75 per
cent N as enriched vermicompost along with diluted liquid organic manures
separately as soil and foliar applications. Plant height, LAI, dry matter
production, number of flowers, number of fruits per plant and total fruit yield
were found to be the highest in T5 (75 % N as EVC + panchagavya 3 % foliar
application). Chlorophyll a, b and total chlorophyll content were the highest in
T10 (75 % N as EVC + jeevamrutha 10 % soil application). T1 (KAU PoP)
recorded the highest average fruit weight. T4 (75 % N as EVC + FAA 5 %
soil application). registered the highest crude protein content while crude fibre
content was lowest in T7 (75 % N as EVC + cow urine 10 % foliar spray).
Ascorbic acid content was the highest in T5 (75 % N as EVC + panchagavya
3 % foliar spray) and was on par with T7, T2,T9 and T11.
The results of the post harvest analysis of soil revealed that pH, EC, organic
carbon and labile carbon contents varied significantly among the treatments.
The highest organic carbon content of soil was recorded by T4 (75 % N as
EVC + FAA 3 % soil application) and T12 (75% N as EVC + vermiwash 10 %
soil application). The maximum labile carbon was recorded by T8. T5 (75 %
N as EVC + panchagavya 3 % foliar spray) was rich in available N. Soil
enzyme activities were influenced by the application of liquid organic
manures. The treatment T5 registered the highest plant uptake of
major
nutrients. The treatment T3 registered the highest plant uptake of secondary
nutrients. The highest value of Fe and Zn uptake was noticed in T11.(75 % N
as EVC + vermiwash 10 % foliar spray). The highest value of Cu uptake was
noticed in T1 (KAU PoP). The highest value of Mn uptake was noticed in T3
(75 % N as EVC + FAA 5 % foliar spray) . The lowest plant uptake of all
nutrients were recorded by T13 (Absolute control). Economics of cultivation
of bhindi indicated that cost benefit ratio was found higher for treatment T5,
75 per cent N as EVC + panchagavya 3 per cent foliar application (2.83)
followed by T7, 75 per cent N as EVC + cow urine 10 per cent foliar spray
(2.09).
From the above study, it was concluded that the recommended dose of
inorganics (KAU PoP) can be substituted with combined application of
enriched vermicompost (enriched with azolla 10 %) to get 75 per cent N and
foliar application of 3 per cent panchagavya or soil application of 10 per cent
cow urine or 5 per cent fish amino acid at 10 days intervals. Soil health, in
terms of physical, chemical, biological and biochemical properties of soil was
more enhanced in the treatments received soil application of liquid organic
manures. Liquid organic manures viz., cow urine, panchagavya, jeevamrutha,
fish amino acid and vermiwash were easily preparable in the farmers’ farm,
biodegradable, less expensive, eco-friendly and non-hazardous for human
health and environment. From the study it was found that above liquid
organic manures were very good organic sources for organic farming and
sustainable agriculture.