Abstract:
Sri Lanka's paddy production plays a pivotal role in ensuring food security
while supporting the livelihoods of the rural communities. Paddy is one of the leading
water consumers globally, and there is a looming concern that the average water use
for paddy cultivation in Sri Lanka is almost twice that of other rice-growing countries.
Sri Lanka has almost exhausted its irrigation potential, and the prospects of develop-
ing additional land and water resources for irrigation are limited. There is little or no
choice but to increase yields to meet its growing food demand. In light of these chal-
lenges, the government's ongoing efforts to modernize agriculture and enhance irri-
gation infrastructure remain crucial for the sustainable growth of the paddy sector in
Sri Lanka. However, the impact of climate change has introduced new obstacles to
paddy cultivation in various regions across the country. Addressing these issues ne-
cessitates an increase in paddy productivity and water use efficiency. This study ex-
amines the variability in paddy productivity within the 53-hectare command area of
the Periya Kalillupai tank and evaluates the efficiency of water use. Data on seasonal
paddy production, rainfall, temperature, tank water levels, and evaporation were col-
lected. Results revealed that the average water use efficiency during the Yala and
Maha seasons were 5.65 kg m-3 and 4.35 kg m-3, respectively. The average paddy
productivity of the Yala and Maha seasons were 4.126 mt ha-1 and 3.439 mt ha-1, re-
spectively. However, it is concerning that both paddy productivity and water use ef-
ficiency showed a decreasing pattern under the Periya Kalillupai tank. Therefore, it is
imperative to emphasize the urgent need for improving water use efficiency and
paddy productivity. This can be achieved through cultivating drought-tolerant rice
varieties, rehabilitating irrigation structures, and adopting efficient water management
techniques. These measures can potentially enhance water use efficiency, ultimately
ensuring the sustainability and growth of paddy production in Sri Lanka.
