MSc

An investigation entitled “Evaluation of thermochemical digest of degradable
waste for container cultivation of chilli” was conducted at the Department of Soil
Science and Agrl.Chemistry, College of Agriculture, Vellayani during 2014-16. The
objective was to develop and standardize a plant growth medium based on custom
blended thermochemical digest of degradable waste for container cultivation of chilli.
The investigation comprised of two parts, one experiment for the standardization of
growth medium based on thermochemical digest of degradable waste (TD) and the
second for standardization of the rate and frequency of application of custom blended
TD fortified with fertilizers for yield maximization in chillies. This was accomplished
through two pot culture experiments with chilli variety Vellayani Athulya.
In the first part, 11 treatments comprising growth medium components viz.
thermochemical digest of degradable waste (TD), coirpith compost (CC) / cocopeat
(CP) and soil in different ratios (1:1:1; 2:1:1; 1:2:1; 2:2:1,1:0:1 and 2:0:1) were
evaluated along with the normal potting medium (Soil: Sand: FYM -2:1:1). The best
growth medium from the above experiment was selected for second experiment. In
the second experiment, three levels of NPK viz. 75%, 100% and 125% of POP at two
levels of application frequency (weekly and biweekly intervals except for P) were
evaluated. The nutrients were applied through fortified TD as per the treatments.
The results of the first experiment revealed that treatment effects were
significant. The treatment T3 (1:2:1) showed highest values for plant height, no. of
primary branches per plant, no. of fruits per plant, length of fruit and weight of fruit.
Highest shoot weight, dry matter, root weight and root volume were observed for
treatment T7 (1:2:1). The treatment T10 (2:0:1) showed lowest values for the same.
While evaluating the soil nutrient status, it was observed that the available nutrient
status increased with levels of TD. The treatment T3 (1:2:1) maintained lowest values
of available P, K, Ca and Mg at final harvest. The treatment T3 (1:2:1) recorded
highest nutrient content in fruit and shoot compared to other treatments except Fe.
Treatment T10 (2:0:1) recorded the lowest values for all nutrients except Fe. Mite
attack was noticed and measures were taken to control it. Economic analysis revealed
that treatment T3 (1:2:1) is having the highest B:C ratio. Hence treatment T3 having
TD, coirpith compost and soil in the ratio 1:2:1 was rated as the best treatment with
regard to yield and economics and hence selected for second part.
In the second part, the individual effects of rate and frequency of fertilizer
application were significant for most of the biometric, root and yield characteristics
of chilli while only a few of their interaction effects were significant. Among the
frequency of application, the weekly application (P1) and among the rate, 100% POP
(F2) were found to be significantly superior to others with regard to growth, yield and
nutrient content. The treatment combination, weekly application @ 100% POP
(P1F2) recorded the highest values and (biweekly application @ 125% POP (P2F3)
showed the lowest values for N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn and B. The
interaction effects were not significant for most of the soil parameters and fruit and
shoot nutrient concentration. In economic analysis the individual as well as
interaction effects were highly significant and followed the same trend.
The investigation revealed that the ideal composition for growth medium
(using thermochemical digest of degradable waste) for container cultivation of
chillies is thermochemical digest, coirpith compost and soil in 1:2:1 proportion.
For yield maximization in chilli, the thermochemical digest of degradable
waste has to be fortified with N P K fertilizers @ 100% of POP and to be applied at
weekly intervals @ 25 g per plant.