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the options are to improve cultural practices that reduce
on-farm water losses, and to increase the efficiency of crop
consumptive water use and improve irrigation efficiency.
Other measures that indirectly contribute to water saving
include irrigation scheduling based on rainfall patterns; crop
performance evaluation to identify critical water-stress-sensi-
tive growth stages; the incorporation of ICT and a geographic
information system (GIS) to improve water delivery services
in irrigation through better water control; land levelling to
improve water management; and the improvement of rain-fed
agriculture through terracing and on-farmwater conservation.
The tail water recovery system for rice cultivation
A tail water recovery system is designed to collect, store and
distribute irrigation or rain water runoff from a farm for reuse
(see figures 1 and 2). If the runoff water is not utilised, it will
eventually flow into the sea. The captured water is pumped
and delivered effectively into a supply system before reuse.
A tail water recovery research project conducted at
MARDI, Seberang Perai has shown that the total amount
of water saved from rice cultivation ranged from 20 to 30%
(see table 1). The ratio of cultivated area to storage pond was
10 to 1. During the planting season, the captured tail water
from excess rainfall was sufficient to supplement rainwater
in order to meet the seasonal water requirement (see figure
3). Since the implementation of the project, no additional
irrigation water has been needed for rice cultivation in the
research plot, showing improved irrigation efficiency and
water saving. Additionally, the residues from chemical appli-
cations were found to be localised to the application areas in
the field rather than distributed to non-target areas such as
collection drains or a storage pond.
Improving the water productivity index
In most cases, the single most important avenue for manag-
ing water demand in agriculture is through increasing
agricultural productivity with respect to water. Increase
in crop yields, i.e. production per unit of land, is the most
important indication of improved crop water productivity.
Yield increases are made possible through a combination
of improved water control, land management, diversity and
agronomic practices. Managing overall demand by focusing
on water productivity is more important than concentrating
on the technical efficiency of water use alone.
Breeding crop varieties with higher water-use efficiency
is seen as providing part of the solution to reduce water
demand. For instance, in a rice crop breeding programme,
two key processes have been exploited to achieve higher
water-use efficiency:
• Reduction in growth duration while maintaining or even
improving crop yield
• Synthesizing more biomass in exchange for water tran-
spired by the crop, i.e. improving crop transpiration
efficiency and planting drought-tolerant varieties.
Table 2 lists some of the improved rice varieties with a short
maturation period and high yield.
Shallow groundwater / tube well
The exploitation of shallow tube-wells for irrigation is suit-
able for short-term crops such as vegetables and field crops
and commonly found near lowland and coastal areas and
used profitably by small farms (see figure 4). During agricul-
Description
Off-season
May–Aug
2014
Main-season
Nov–Mar
2014/2015
Off-season
May–Aug
2015
Rainfall during growth
period (mm)
768
940
798
Direct pumping from
storage pond (mm)
322
247
264
Total water supply (mm)
1,090
1,187
1,062
Water saved by
recycling (%)
29.5
20.8
24.8
Net withdrawal from
storage pond (m
3
)
793
1092
293
Estimated energy cost
Total amount of water
pumped (m
3
)
27,270 20,940 22,300
Total amount of diesel
used (L)
330
235
300
Total cost of diesel (RM)
(RM 2.20/L)
726
517
660
Energy cost per ha (RM)
85.80
61.10
78.0
Table 1: Water saving in tail water recovery system
Ratio of cultivated area to storage pond: 10:1
Currency conversion: US$1 to RM 4.2
Varieties
Maturation*
main season – off season
Potential
yield (mt/ha)
Bajong/Biris
160–170
3
Bario/Mamut/Bubuk
140–160
3
Malinja
137–147
4
Setanjung
135–142
5
Mahsuri
134 –138
5
MR 84
124–137
7
MR 127
120–128
7
MR 211
99–100
8
MR 185
112–119
8
MR 219/ MR220
105–120
10
MR 253/MR263
104–110
10
MR 220 CL1 & CL2
97–113
10
MR 284
105–110
10
MR 297
100–110
10
Table 2: Increased water productivity through reduced
growth duration and increased yield
*Maturation measured in number of days after sowing
Source: Malaysian government
Source: Malaysian government