Table 1 displays the CAGR in area, production and productivity of turmeric over three phases (2001-2010, 2011-2021 and 2021-2021). The results reveal incredible growth rates in the area (18.95%), production (19.91%) and even productivity (6.04%) over the first 2000-2011 decade. The growth rate was favourable at 4.29% and 5.14% in areas and productivity, with a significant increase in productivity (10.12%) from 2011 to 2022 compared to period I (2001 to 2011). Between Period III, 2000-01 and 2020-21, the overall period saw an 8.74% increase in area and 10.92% increase in production and modest annual increase in productivity of 0.30 per cent annually.It shows there has been a rapid increase in area, production and productivity after MOMA (Manipur Organic Mission Agency) began in 2016 in Manipur. Their studies also observed the increasing trends in area, production and productivity in various parts of the state, including vegetable crops. The study revealed high instability in the area under turmeric in Manipur during period I (2001-02 to 2010-2011) at 190.17 which replicated in period III overall (2001-02 to 2020-21) at 133.22. Productivityshowed some moderate instability, ranging from 31.15 to 38.63 and medium instability, around 20.57 to 22.62 in productionindicating volatility in the area (period I) and productivity throughout the period (Table 1 and Fig 1).
Table 2 reveals a decrease in annual trends in climate variables in Manipur, with the maximum trend in rainfall being -6.07% and the minimum trend at wind direction being - 0.09%. The temperature during that period was averaged at 20.02
oC, with maximum temperatures at 30.91
oC and minimum temperatures at 12.29
oC. The relative humidity level was averaged at 77.13%, with maximum and minimum values of 96.29% and 23.12%, respectively.The wind speed was 2.16 meters per second, with a wind direction of 175.04 and the solar radiation was 899.42 Watts/mtr
2. From 2013 to 2022, the average annual rainfall was 95.25 mm. The solar radiation showed the highest standard de
viation, followed by rainfall, which showed significant variation, with a standard deviation of 43.44 and 34.98 respectively. The wind speed, maximum relative humadity and maximum temperature displayed a lesser standard deviation, indicating a meager de
viation from the mean value. The revealed high instability in rainfall at 37.94, indicating higher volatility persistence and medium instability in wind speed at 21.67, while low in temperature, relative humidity, wind direction and solar radiation.
Table 3 display the trends of various climate variables from 2013 to 2022. According to the findings, the average temperature ranges between 14.04
oC and 21.08
oC in 2022 and 2016, respectively. And the maximum temperature fluctuated from 25.66
oC to 32.45
oC in 2022 and 2019 respectively where as the minimum temperature fluctuated from 5.02
oC in 2022 to 14.37
oC in 2013. The relative humidity in Manipur state ranged from 74.72% to 80.19% in 2013 and 2016, respectively. The maximum relative humidity was highest during 2014 was 98.95%, while the lowest was 94.11% in 2020. The minimum relative humidity ranged from 25.07 to 35.88% in 2022 and 2013, respectively. In 2018, the highest wind speed of 3 metres per second was recorded and during 2022, recorded the highest wind direction at 198.60, whereas 2020 had the solidest sun radiation at 935.52 watts per m
2. The state experienced varying rainfall levels in 2022 and 2018, with less rainfall in 2022 (24.71 mm) and the highest in 2018 (108.59 mm), with an average rainfall of 95.25 mm, indicating significant rainfall fluctuations.
The autocorrelation function (ACF) of a time series is represented visually by a correlogram for stationarity. The ACF has been computed for climate variables for time series data with lag (-1) between 2013-14 and 2021-22. Result in Fig 2 shows the eight lags that were found for that period. The results of the correlogram for several climate variables, including temperature (
oC), maximum temperature (
oC), minimum temperature (
oC), relative humidity (%), wind speed (mtrs/sec), wind direction (o), solar radiation (Watts/mtr
2) and rainfall (mm) reveals that there are distinct and more fluctuations and making it difficult to detect the true signal or pattern within the data over the period for all the variables. It clearly shows that, time series data is non stationary (Fig 2).
Results of Augmented Dickey-Fuller test to determine whether climate variable and turmeric production time series are stationary or non-stationary for Manipur state have been worked out and represented in Table 4. The results show that turmeric crops’ area, production and productivity were determined to be stationary and also indicating that 1 per cent significance and does not depend on their time-dependent structure.Among the climate variables, RH (%), Wind Speed (mtrs/sec), WindDir. (o), Solar Rad. (Watts/mtr
2) and Rainfall (mm) were non-stationary in nature and not statistically significant except wind speed which is significant at 10%. The maximum and minimum relative humidity were stationary and the maximum relative humidity is significant at 1%.
Table 5 shows the results of causal relationship between the area, production and productivity of the turmeric crops and the main meteorological variables. The findings indicate that the area and production are both significantly positively corrected, with a value of 0.970. The study found a significant positive correlation between solar radiation and productivity, with a value of 0.737, indicating its significant role in enhancing productivity. Solar radiation significantly influences turmeric productivity in state due to its seasonal impact on photosynthesis and rhizome development unlike temperature and humidity, is crucial for turmeric to thrive and produce high-quality rhizomes. Although, the maximum temperature is moderately correlated with area and production of turmeric, which have values of 0.586 and 0.588, respectively, which shows mild temperature is crucial for the production of turmeric.