PhD

The study' on the formulation and evaluation of organic meals from KCPL effluent
slurry was conducted at KCPL (Kerala Chemicals and Proteins Ltd.) factory site and
at College of Horticulture, Vellanikkara during May, 1997 to December, 1999. Being a
new material sequential steps involving the study of the basic properties of KCPL
sludqe, standardisation of formulation techniques of organic meals, analyzing of
physico-chemical properties of the organic meals, direct and residual effect of
selected organic meal on crop and soil were conducted during the period.
Drawing composite samples three times every month at 10 days interval for a period
of six months from May, 97 to October, 97 the basic properties were evaluated. An
incubation study was conducted to understand the availability and release pattern of
nutrients. The sludge along with mussorie rock phosphate was incubated for 120
days at three levels of 1 g, 2g and 4g P per five kilogram of soil at three moisture
regimes 50FC, FC and water logging, drawing samples at 30 days interval for
analysis. Various formulation techniques were tried to develop organic meals in a
quick and cost effective manner. Organic meals were produced from spent slurry
obtained after biomethanation of KCPL sludge. Signa led from an accidental
observation principles of activated composting was employed to evolve a cost
effective and quick method for preparing organic meals. Exhaustive pot culture and
field experiments besides on farm trial in farmers fiela (Kole lands of Thrissur) were
conducted to test the manurial quality and acceptability of the organic meals.
From the basic properties evaluation studies it was confirmed that KCPL sludge is a
nutrient rich uniform organic source containing 1.86 % N, 8.44 % P, 20.34 % Ca and
appreciable quantities of other major and minor nutrients. The heavy metal contents
were below the permissible limit rendering it chemically safe for fertilizing the soil.

Because of its high Ca and neutralizing value it can also be a good soil conditioner.
From the incubation study it was found that KCPL sludge was superior to rock
phosphate in the release of major nutrients. More over peak release of all nutrients
occurred within the 60 days period and it could be successfully used as an organic
source both under aerobic and waterlogged situation.
The principle of aerobic composting was standardized as the best formulation
technique for the production of organic meals. Good quality composts could be
produced within a period of 90 days by the open heap method. Among the compost
maturity parameters maximum microbial population were in the thermophilic stage.
Temperature (70°c) and pH (8) also attained maximum values at this stage. C/N ratio
stabilized around 12.51 after 90 days. There was not much variation in the above
characters due to the covering techniques. But the pit system of composting failed to
achieve the required level of thermophilic environment for composting
Based on ease in formulation technique and favourable physico-chemical properties
the meal No.1 (sludge + 5% neem cake + 5% mussorie rock phosphate + 1 % urea)
was adjudged superior over the rest of seven formulations. It contains 1.79 % N,
9.05 % P, 0.28 % K, 16.96 % Ca, 0.32 % Mg and 0.36 % S. The Fe, Mn, Zn and Cu
content are 883.5, 103.62, 113.3 and 7.71 ppm respectively. pH of this meal is 6.97,
organic carbon 22.38 %, C/N ratio 12.51and neutralizing value 71.22.
From the pot culture study it was inferred that organic meals even at higher levels
were not harmful to the crop, but lower doses of meal alone will not be able to meet
the nutrient demand of the crop.
Field investigations with organic meal showed that it improved the growth and yield
of rice crop when used in combination with inorganic fertilizers besides providing the
balanced supply of all nutrients as required by the crop. In general there was no

significant variation between the different levels of organic meal with respect to
either growth or yield components. The highest yield of 5.01t was obtained from-
OM 20 % NPK. With respect to both growth and yield characters the lowest dose of
5 tlha was always comparable to the recommended practice of crop nutrition.
Residual study proved that organic meal could serve as a good residual P source.
The growth and yield components at the lowest level of OM 5 tlha was comparable to
higher levels even during second successive residual crop. Economic yield of 4.11 t
was observed in OM 5 NPK. Moreover soil P status also improved in the successive
seasons. Application of P can be skipped for two seasons at higher levels of
10-20 tlha and this can sustain higher yields.
The on-farm trials also showed that organic meal could be a good organic P source
even at very low levels of 1.25 tlha when used with inorganic fertilizers. The
desirable direct as well as residual effects of organic meal were manifested
continuously for two seasons even with doses in the range of 1.25 to 5 tlha of
organic meal.