Abstract:
The impact of the mountain cropping system on groundwater quality and soil heavy metal accumulation
was studied in mid-hills of Solan and Kullu districts of Himachal Pradesh. To assess the impact of
dominant cropping systems, the four commonly occurring systems, namely vegetable, fruit, cereal
crop and agroforestry were selected in the area ranging from 800-1800m. Uncultivated land in the
region was considered as control. In total, there were five treatments which were replicated six times
under randomized block design. The study was conducted for two years, i.e. during 2014 and 2015.
The study indicated that the mountain cropping systems varied significantly with respect to their
impact on groundwater quality and soil heavy metal accumulation. The pH, electrical conductivity,
chlorides, nitrates and sulphates in groundwater were within drinking water permissible limits prescribed
by Bureau to Indian Standards (BIS). The concentration of zinc, arsenic and nickel in groundwater
was also within drinking water critical limits prescribed by BIS but lead and cadmium exceeded the
limits. The concentration of lead and cadmium ranged from 0.12 to 0.27 mg L-1 and 0 to 0.02 mg L-1
,
respectively, and followed similar crop system-wise trend, i.e. vegetable > fruit > agriculture >
agroforestry > control. The soil accumulation of zinc, arsenic and nickel was within permissible limits
prescribed by WHO but lead and cadmium violated the limits. Interestingly, soil accumulation of lead
exceeded WHO permissible limits under all cropping systems, including the control. The accumulation
of lead and cadmium in soil ranged from 0.16 to 0.44 mg kg-1 and 0.02 to 0.12 mg kg-1, respectively, and
had a similar crop system-wise trend they had in groundwater. Therefore, to maintain the quality of the
important natural resources like groundwater and soil in mid-hills of Himachal Pradesh, necessary
steps need to be taken.
