| Summary: | 碩士 === 國立屏東科技大學 === 土壤與水工程國際碩士學位學程 === 106 === Abstract
The system of rice intensification (SRI) is a friendly-environment rice
production system that has been proved to reduce the water consumption and
production inputs when at the same time increase yield and water productivity.
With the increasing water scarcity due to climate change, water reduction in
production is a permanent research issue. The present investigation was
carried out to evaluate the effects of different water regimes on the growth
parameters and yield attributes of rice under SRI in dry season as well as their
related water productivity in irrigated rice, using alternate wetting and drying
water management by observation. The study aimed at finding out the
optimum irrigated water depth applied to SRI in Taiwan tropical dry season.
The experiment was conducted at irrigated rice field in National Pingtung
University of Science and Technology (NPUST). SRI management principles
such as plant spacing, seedling densities, duration of planting and weeding
method have been thoroughly conducted. Five (5) different water depths
including the control plots were tested. The control irrigated at 3cm water
depth at soil hairline cracks (SRI3) was compared to 2cm (SRI2), 4cm (SRI4)
and 5cm (SRI5) water depth under alternate wetting and drying (AWD)
irrigation based on visual observations, and also to 3cm water depth per week
(SRI3/w), previously identified as optimum water depth. Growth parameters
like plant height, leaf area index (LAI), chlorophyll content, and yield
attributes such as tillers number, productive tillers number, tillering efficiency,
panicles number, panicles length and weight, spikelets number, filled
spikelets ratio, 1,000 grains weight, total grain yields and water productivity
were assessed. The results showed that the application of 3cm at soil hairline
cracks (SRI3) recorded the highest values in most of the growth parameters as
well as in the yield attributes. The investigation revealed also that significant
differences were observed during some development stages between the different water treatments in the growth parameters assessment as well as in
the yield attributes analyses. Yield attributes like spikelets numbers per meter
square and filled spikelets percentage were determinant for the grain yield.
SRI3 yielded better with 4072kg/ha compared to SRI2 (3448kg/ha), SRI3/w
(3340kg/ha), SRI4 (3081kg/ha and SRI5 (2604kg/ha). The highest water
productivity was recorded in SRI3 at soil hairline cracks (0.19kg/m 3 ) whereas
SRI2 at soil hairline cracks and SRI3/w obtained both 0.18kg/m 3 . Even
though they received much water, SRI4 and SRI5 at soil hairline cracks
recorded the lowest water productivity with respectively 0.15kg/m 3 and
0.12kg/m 3 of water. The effects of weather conditions on the growing cycle,
added to the water stress imposed to rice, resulted in grain yield decline and
low water productivity. The findings suggested the application of 3cm water
depth after reduced soil hairline cracks as an optimum water treatment for SRI
in dry season. Rice cropping period should also be adjusted to avoid the
critical temperatures.
Key words: System of Rice Intensification (SRI), soil hairlines cracks,
growth parameters, yield attributes, optimum water depth.
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