Vol. 9 No. (2): 102 - 119 (2018): EFFECT OF MULCH AND IRRIGATION ON GROWTH AND WATER USE EFFICIENCY OF LETTUCE (Lactuca sativa L.) CULTIVARS

A study was carried out to evaluate effect of mulch and irrigation on growth and water use
efficiency of lettuce (lactuca sativa L.) cultivars under irrigation during 2016, 2017 and 2018
in semi-arid ecology of Northern Nigeria at Irrigation Research Sub-Station farm (IRS) of the
Institute for Agricultural Research, Ahmadu Bello University at Kadawa, (110 39/ N, 0800
027/ E and 500 m above sea level) in the Sudan Savanna Ecological Zone of Nigeria.
Treatments were factorial combinations of three irrigation levels (50, 75 and 100 % of
reference evapotranspiration (ETo), three lettuce cultivars (Great Lake, Slaai and Baby leaf
mix) and two levels of mulch (no-mulch and mulch) laid out in a split plot design with three
replicates. Water applied before and after irrigation was monitored throughout the seasons.
Results indicated that different levels of irrigation and mulch on all growth characteristics,
crop water use efficiency and irrigation water use efficiency were significant with the highest
irrigation level of 100 % ETo recording the highest yield of 8.5, 8.4 and 8.6 tonnes ha-1 in
2016, 2017 and 2018 seasons respectively while 50 % ETo recoded the least yield of 7.3, 6.7
and 7.5 tonnes ha-1 across the three years. Increase in water application increase yield of
about 7.6% in 2016; 11.6 and 10.6 % in 2017 and 2018 respectively with 100% ETo.
Mulching significantly improved the crop water productivity irrespective of the cultivar in
the study area. Since there were only minor differences between growth characters of lettuce
obtained from 75 and 100% ETo, it can be said that water application should be kept at 75%
weekly crop consumptive use in this region.