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Explora: Environment
and Resource Climate change and apple yield

Figure 2. Trend of snowfall

pollutants, climate variables, and crop yield is shown in
Table 4.

3.5. Chill units and apple yield trend
The chill units calculated using the UTAH model were
subjected to trend analysis. Figure 4 shows the trend
of chill units for the period from 1991 to 2018. The
analysis yielded a Sen’s slope of -7.5 and a P-value of
0.042, indicating a significant decline in chill units over
the past 28 years in the apple cultivation areas of Shimla.
Similar observations of a decrease in the chill units in the
other district of Himachal Pradesh have been reported.
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The decline in the snowfall is a major reason for the
drop in chill units. Figure 5 depicts a similar declining
trend in the apple crop yield throughout the study from
6.6 tonnes/ha (1991) to 3.2 tonnes/ha (2018). Apple yield
showed negative trends over a period of 28 years with
a Sen’s slope of -0.028 and a P-value of 0.034, whereas
the area for apple cultivation had expanded, with a Sen’s
slope of 2081 and a P-value of 0.007. Taken together, the
climate change, especially the changes in temperature
over time, has a huge impact on the chill units and thus
the apple yield.

Figure 3. Trend of changes in air pollutant concentration (CO, CO , and 3.6. Correlation matrix
2
NO )
x The correlation among CO, CO , NO , snowfall, chill
x
2
unit, apple yield, temperature, and rainfall was analyzed
results that the increasing concentration of CO leads to using SPSS version 20. The results of which are presented
x
global warming. Furthermore, high temperatures could be in Table 4. CO had a significantly positive relationship
attributed to the increased CO . These pollutants usually with NO , chill unit, temperature, and rainfall, but was
x
x
originate from burning of fuels, biomass, industrial significantly negatively correlated with snowfall and apple
emissions, vehicular emissions, and natural sources. The yield, indicating that an increase of CO concentration may
correlation matrix showing the relationship between result in a decrease of snowfall and apple yield. On the
Volume 1 Issue 1 (2024) 5 doi: 10.36922/eer.3608