MSc

Turmeric (Curcuma longa L.) is an annual tropical herb originated and cultivated in
India and is used as spice, condiment, dye, drug and cosmetic. It is also known as
“golden spice” or “Indian saffron”. India is the largest producer of turmeric in the world
and contributes 80% of the world production. In India, turmeric is mostly grown as
rainfed crop and mulching is an important component in the management practices. In
the dry months, mulching conserves the moisture in the soil and enhances soil
temperature for proper germination of the rhizome. The present study is aimed to
evaluate the yield characteristics of turmeric crop with organic mulches under different
dates of planting and assess climate change impact under projected climate change
scenarios. Turmeric variety Kanthi was raised at Instructional Farm, College of
Agriculture, KAU, Vellanikkara, in split plot design with four different dates ofplanting
(June 1st, June 15th, July 1st and July 15th) as main plot treatments and three different
mulching treatments (green leaves, paddy straw and dry coconut leaves) as sub plot
treatments.
The crop period was divided into four phenophases (P1-planting to germination,
P2-germination to initiation of active tillering, P3-initiation of active tillering tobulking,
P4-bulking to physiological maturity). June 1st and June 15th plantings took more days
to reach physiological maturity. Crop weather analysis was done by using SPSS
software. The plant biometric characters like plant height, number of leaves, leafarea,
number of tillers and dry matter accumulation were found to be more in earlier dates of
planting (June 1st and June 15th). In mulching practices, paddy straw mulch was found
to be superior followed by green leaf mulch. In most of the biometric and yield
observations, both these mulches were found to be on par with each other. The yield
produced by crops planted on June 1st date of planting were higher and in case of
mulching treatments,paddy straw mulch produced superior yield than other mulches.
Yield of turmeric had shown significant negative correlation with maximum and
minimum temperature, forenoon and afternoon relative humidity during the bulking
stage, but the yield is having a positive correlation with forenoon and afternoon relative
humidity which maybe the reason of high yield in paddy straw mulch.
Crop yield prediction models in all the phenophases using principal component
analysis of mulching treatments and dates of planting were done and the yield of
turmeric crop with the respective equations were predicted. Predicted yield was in
accordance with the observed yield in all mulching treatments.
The impact of date of planting and mulches on the yield of turmeric under different
climate change scenarios of RCP 4.5 and RCP 8.5 showed that yield varied inthe coming
centuriesi.e., near century (2010-2039), mid-century (2040-2069) and end century(2070-
2099) with respect to base period. In green leaf mulch, turmeric yield was seen tobe
decreasing in first date of planting (June 1st) under both RCPs. The base period yieldwas
20018.5 Kg ha-1
in June 1st plantings. It was decreased to 19809.4 Kg ha-1
in near century,
19491.3 Kg ha-1
in mid-century and 19440.15 Kg ha-1
in the end of century under RCP
4.5. The percentage yield decrease was 1.04%, 2.63% and 2.89% in, near century, midcentury and end of century respectively. The yield was reduced to 19468.6Kg ha-1
in near
century, 19379.4 Kg ha-1
in mid-century and 18997.6 Kg ha-1
in the endof century during
RCP 8.5.
An increase in the percentage yield decrease was seen compared to that of the RCP
4.5 scenario. It was 2.75% in near, 3.19% in mid and 5.1% in end of century. In case of
paddy straw mulch, yield is expected to decrease in near century under all dates of
planting except July 1st planting under both the scenarios. In July 1st planting, the yield
is expected to increase by near century and by end century, it is expected to decrease
under both scenarios. The base period yield was 21514.7 Kg ha-1
in June 15th plantings.
In RCP 4.5 yield was seen to be decreasing by 21241.6 Kg ha-1
in near century, 20457.5
Kg ha-1
in mid-century and 20279.7 Kg ha-1
in the end of century. The percentage yield
decrease was 1.27%, 4.91% and 5.74% in near century, mid-century and end of century
respectively. The base period yield during D3 (July 1
st) was 15772.7 kg ha-1
under RCP
8.5. An increase in yield during all time scales in D3 plantings was seen under RCP 8.5
scenario when compared to RCP 4.5. The percentage increase in yield was highest
(3.27%) during near century. Higher increase in yield was observed in mid-century
during July1st planting in RCP 8.5 in dry coconut leaf mulch. June 15th and July 15th
plantings showed the highest percentage of yield reduction during near century. Highest
increase in yield was found at the end of century during July 15th date of planting.
Under 8.5 scenario, highest reduction in yield was found to be in June 1
st
, June 15th and
July 15th plantings under dry coconut leaf mulch in the near century (2010-2039). The base
period yield during June 1st was 11768.5 Kg ha-1
and it was increased to 12161.6 Kg ha-1
in
near century, 11791.1 Kg ha-1
in mid-century and 12092.1 Kg ha-1
towards the end of the
century. The base yield on June 15th was 10842.7 Kg ha 1
. A decrease in yield of 10605.4
Kg ha-1
and 10725.1 Kg ha-1 was observed during near and end of century respectively. The
third date of planting i.e., July 1st yielded 9658.4 Kg ha-1
during base period. Decrease in
yield of 8966.8 Kg ha-1
in near century, 8625.8 Kg ha-1
in mid-century and 8977.6 Kg ha-1
in end of the century from base period yield was seen during all time slices. The base yield
during July 15th planting was 6812.9 Kg ha 1
. An increase in yield of 7348.8 Kg ha-1
, 7536.7
Kg ha-1
and 7287.8 Kg ha-1
in near, mid and end of the century towards the last date of
planting i.e., July 15th
.
The decrease in yield may be due to the variation in temperature and rainfall. Under
projected conditions, the temperature was expected to increase at the same time the
rainfall was expected to decrease. This might have contributed to the yield reduction in
future. It can be stated that it’s not necessary that an increase in rainfall will always lead
to increase in yield. Similarly, an increase in maximum temperature may not, at all times
negatively affect the yield of turmeric. The weather parameters experienced during each
phenophase decides the trend of increase or decrease in yield. There was asignificant
effect of maximum temperature on the yield of turmeric which might be thereason for
the decreased yield of turmeric in the projected climate change scenarios.
The yield reduction under projected climate change scenarios RCP 4.5 and RCP
8.5 are related to the changes of different weather parameters from the required optimal
level. The maximum temperature was found to increase in the future under both
scenarios and the amount of precipitation showed a decreasing trend from the observed
base period values. The yield reduction under projected climate change scenarios were
in agreement with the increase in maximum temperature and reduction in rainfall.