December, 2013
International Agricultural Engineering Journal
Vol. 22, No. 4
49
Effect of various micro irrigation treatments on growth and yield response of aerobic rice T. Parthasarathi1*, S. Mohandass1, S. Senthilvel1, Eli Vered2 (1. Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India; 2. Netafim Irrigation, Derech Hashalom, Tel Aviv, Israel 67892) Abstract: Drip irrigation studies were conducted in aerobic rice during Dry Season (DS), 2011 and Summer Season (SS) 2012 in Coimbatore, Tamil Nadu, India.
Drip irrigation treatments comprised of three levels of lateral distance (0.6, 0.8 or 1.0 m
lateral distance) with the two discharge rates (0.6 or 1.0 L h-1 emitters) in DS 2011.
In SS 2012, the micro irrigation
treatments namely; surface, sub surface drip irrigation (SDI) with two discharge rates (0.6 or 1.0 L h-1 emitters) with 0.8 m lateral distance and a lysimeter based irrigation treatment were applied.
Among the lateral distances, 0.8 m lateral distance
registered as the optimum spacing for the better performance in root characters, growth and yield attributes than rest of the lateral distances.
From the surface-drip and sub-surface drip irrigation (SDI) treatments, the SDI performed better in terms of Among the discharge rates, 1.0 L h-1 drippers outperformed 0.6 L h-1 drippers in
root character, growth and yield attributes.
terms of water use efficiency and grain yield.
Interactively, laterals spaced at 0.8 m with 1.0 L h-1 drippers laid sub
surface-drip through fertigation exhibited better performance in terms of root parameters (such as root length, Root Mass Density, root biomass and root volume) along with growth attributes (Leaf Area Index, Specific Leaf Weight, Crop Growth Rate and Net Assimilation Rate), yield and its components (such as productive tillers, spikelet numbers, filled grain percentage and Harvest Index) along with water productivity when compared with the conventional irrigation treatment.
Therefore, it is
-1
suggested that the lateral spacing of 0.8 m with 1.0 L h drippers when the plants spaced at 20 cm × 10 cm with SDI through fertigation is adjudged as the best treatment for aerobic rice cultivation in enhancing the values for water productivity and grain yield in areas of limited water availability. Keywords: aerobic rice, discharge rates, lateral distance, drip irrigation Citation: Parthasarathi, T., S. Mohandass, S. Senthilvel, and E. Vered. growth and yield response of aerobic rice.
1
Introduction
2013.
Effect of various micro irrigation treatments on
International Agricultural Engineering Journal, 22(4): 49－62.
Mochizuki, 2009). The wasteful and harmful system of
flood irrigated rice cultivation practiced widely in South Agriculture consumes 70% of the fresh water
Asia must be replaced with furrow, drip or sub-irrigation
resource, but less water is becoming available for
systems (Aujla et al., 2007). Application of uniform and
irrigation owing to the global climate change and
sufficient water to seed for good crop establishment is one
competition
of the most challenging issues of surface drip and
from
urbanization
and
industrial
development (Pennisi, 2008). ‘Aerobic rice culture’ is
subsurface drip irrigation (Camp, 1998).
an emerging cultivation system aiming to maximize crop
Rice plants under aerobic systems undergo several
water productivity (yield/water input) by growing plants
cycles of wetting and drying conditions (Matsuo and
in aerobic soil without flooding or puddling (Matsuo and
Mochizuki, 2009). Rice performance in aerobic culture might be improved through manipulation that promotes
Received date: 2013-07-16 Accepted date: 2013-11-12 * Corresponding author: T. Parthasarath, Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India. Email:
[email protected].
lateral root branching and rhizogenesis as well as deep rooting (Richards, 2008; Kato and Okami 2011). Kondo et al. (2003) found significant differences in rooting
50
December, 2013
International Agricultural Engineering Journal
Vol. 22, No. 4
characteristics, especially deep rooting depth and root
growth attributes, root growth, and yield responses
biomass, among various (aerobic and upland) rice
consisting of three lateral spacings with two level of
varieties. Leaf Area index (LAI) is more likely to be
emitter discharge rate. In SS 2012, the objectives were
restricted in aerobic culture than in flooded culture as a
to compare the performance of sub-surface drip (SDI) and
result of frequent soil drying (Sudhir et al., 2011).
surface drip irrigation methods and discharge rate for
Gowri (2005) reported that under aerobic condition PMK
better grain yield, water requirements, water productivity,
3 recorded higher crop growth rate than ADT 43.
growth attributes, root growth, and yield responses
Application efficiency of different surface and
consisting of two irrigation methods and two levels of
pressurized irrigation methods varies and depends on
emitter discharge rates by varied micro-irrigation treatments.
design, management and operation (Holzapfel and Arumí,
2
2006).
Materials and methods
Quantification allows determining and control
dripper discharge, amount and timing of application of
The experiment was conducted during Dry Season
irrigation water so that the crop water requirements are
2011 (DS 2011) and Summer Season 2012 (SS 2012) in
met in a planned and effective manner (Enciso et al.,
the wetlands of Tamil Nadu Agricultural University,
2005). Karlberg et al. (2007) reported that two low-cost
Coimbatore, Tamil Nadu, India situated at 11º N latitude,
drip irrigation systems with different emitter discharge
77º E longitude and at an altitude of 426.7 m above Mean
rates were used to irrigate tomatoes and concluded that
Sea Level.
combination of drip systems with plastic mulch increased
Block Design was adopted with three replications using
the yield.
Water and/or nitrogen management system
ADT (R) 45 as the test variety. The irrigation was given
that could increase growth rate during grain growth
through PVC pipe (50 mm OD) after filtering through the
and/or enhance the remobilization of assimilates from
screen filter by 7.5 HP motor from the bore well. The
vegetative tissues to grains during the grain-filling period
pressure maintained in the system was 1.2 kg cm-2.
usually leads to a higher HI within a crop (Ju et al., 2009).
From the sub-main, in-line laterals were laid at a spacing
Increasing the number of spikelets should be a primary
of 0.6 m, 0.8 m and 1.0 m with 0.6 or 1.0 L h-1 discharge
target, as this has helped to increase the yields of aerobic
rate emitters positioned at a distance of 30 cm.
rice (Peng et al., 2008). Xue et al. (2007) reported that
Irrigation was given based on the Open Pan Evaporation
-1
the average yield of aerobic rice was 4.1 t ha
with
Field experiment design of Randomized
(PE) values (125% PE) from USWB Open Pan
688 mm of total water input in 2003 and 6.0 t ha-1 with
Evaporimeter.
705 mm of water input.
Aerobic rice could be
account while scheduling irrigation under surface drip
successfully cultivated with 600 to 700 mm of total water
(DI) and sub-surface drip (SDI) methods. The effective
in summer and entirely on rainfall in wet season (Shailaja,
rainfall was calculated using water balance sheet method
2007). Aerobic rice varieties will possess large numbers
(Dastane,1974). The physiochemical properties of the
of spikelets and sufficient adaptation to aerobic
soil samples from the experimental site are analyzed and
conditions such that they will consistently achieve yields
furnished in Table 1.
The effective rainfall was taken into
comparable to the potential yield of flooded rice (Kato et
The weather parameters prevailed during cropping
al., 2009). There are only few attempts to address the
season was observed in Agromet Observatory in Tamil
physiological responses of rice and critical analysis of
Nadu Agricultural University, Coimbatore, Tamil Nadu,
various yield components to aerobic conditions (Bouman
India (Figure 1).
et al., 2005).
temperature were 30.9ºC, 34.2ºC, minimum temperature
The average values for maximum
Considering the above, objectives of DS 2011 study
of 22.7ºC, 23.3ºC, sunshine hours of 5.4, 7.3 h per day
were set out to study the performance of aerobic rice,
and total evaporation was 628.3 and 750.4 mm with the
optimize the lateral distance and discharge rate for better
total precipitation of 532.7 and 118.6 mm during DS
grain yield, water requirements, water productivity,
2011 and SS 2012 respectively.
December, 2013
Effect of various micro irrigation treatments on growth and yield response of aerobic rice Table 1
Vol. 22, No. 4 51
Soil physical and chemical properties of experimental site
Season
pH
EC/dS m-1
Organic carbon %
Available N/kg ha-1
Available P/kg ha-1
Available K/kg ha-1
DS 2011
7.7
0.53
0.64
284
21
349
SS 2012
7.8
0.58
0.61
301
23
325
Figure 1
Weather data prevailed during cropping season (Dry Season 2011 and Summer Season, 2012) in Coimbatore, India
In Dry Season (2011), there were eleven treatments
between plants + 30% more water (T7), lateral distance of
employing three lateral spacing and two discharge rates
1.0 m, spacing of 20 cm between rows of plants and
of emitters.
The treatments were distance between
spacing of 10 cm between plants + 30% more water (T8),
laterals 0.6 m with the spacing of 20 cm between rows of
lateral distance of 0.8 m, spacing between rows of plants
plants and spacing of 10 cm between plants (T1), distance
from lateral (5×20×30×20×5) (instead of four rows of
between laterals 0.6 m, spacing between rows of plants
20 cm each) with 0.6 L h-1 drippers (T9), lateral distance
from lateral (20×10×10×20) (instead of three rows of
of 1.0 m, spacing between rows of plants from lateral
20 cm each) (T2), lateral distance of 0.8 m, spacing of
(7.5×15×15×empty bed (25 cm) × 15×15×7.5) (instead of
20 cm between rows of plants and spacing of 10 cm
five rows of 20 cm each) with 0.6 lph drippers (T10).
between plants (T3), lateral distance of 0.8 m, spacing
In SS 2012, there were ten treatments employing two
between rows of plants from lateral (5×20×30×20×5)
discharge rates and two irrigation methods (Surface and
(instead of four rows of 20 cm each) (T4), lateral distance
subsurface laterals).
of 1.0 m, spacing of 20 cm between rows of plants and
distance of 0.8 m, row spacing of 20 cm with dripper
spacing of 10 cm between plants (T5), lateral distance of
flow rate 1.0 L h-1 SDI (T1), lateral distance of 0.8 m, row
1.0 m, spacing between rows of plants from lateral
spacing of 20 cm with dripper flow rate 0.6 L h-1 SDI (T2),
(7.5×15×15×empty bed (25 cm) ×15×15×7.5) (instead of
lateral distance of 0.8 m, row spacing of (5×20×30×20×
five rows of 20 cm each) (T6), lateral distance of 0.8 m,
5) cm with dripper flow rate 1.0 L h-1 SDI (T3), lateral
spacing of 20 cm between rows and spacing of 10 cm
distance of 0.8 m, row spacing of 20 cm with dripper
The treatments were lateral
52
December, 2013
International Agricultural Engineering Journal
Vol. 22, No. 4
flow rate 1.0 L h-1 on surface (T4), lateral distance of
Pendimethalin 30% EC at 1.25 a.i kg ha-1 and two time
0.8 m, row spacing of 20 cm with dripper flow rate 0.6
hand weeding controlled the weeds. Fertilizer dose of
on surface (T5), lateral distance of 0.8 m, row
150:50:50 kg ha-1 of NPK in the form of water-soluble
spacing of 20 cm with dripper flow rate 1.0 L h-1 + 30%
fertilizers was supplied through fertigation by the ventury
more water on surface (T6), lateral distance of 0.8 m, row
flume at a rate of weekly interval splits. Installation of
spacing of (5×20×30×20×5) cm with dripper flow rate
lysimeter in the treatment T8 was fixed in the field and
L h
-1
-1
1.0 L h + 30% more water on surface (T7), irrigation
height of lysimeter rim was maintained near the ground
according to lysimeter (20% drainage at depth of 60 cm
level. The dimension and details of lysimeter are given
from surface) (T8), lateral distance of 0.8 m, row spacing
in Figure 2.
of 20 cm with dripper flow rate 1.0 L h
-1
The row spacing and plants within the row
SDI + 150
were adjusted to give equal density in and around
kg K2O ha (T9) and conventional irrigation at IW/CPE
lysimeter. Rice crop in the lysimeter was grown under
ratio of 1.25 at 30 mm depth of irrigation (conventional
aerobic condition by using drip irrigation with 1.0 L h-1
irrigation) (T10).
drippers. The drained water collected at the bottom of
-1
Regarding
the
crop
management
aspects,
the peizometer was pumped daily. Irrigation was given
recommended cultivation practices were followed for
to the treatment T8 according to 20% drainage at depth of
aerobic rice. Application of pre emergence herbicide,
60 cm from surface of lysimeter.
Figure 2
Lysimeter top and side views
To measure the root growth, the roots were removed
Root biomass values were expressed as g m-2. The plant
carefully from the soil without damaging the roots
growth attributes were measured at flowering stage of the
measuring the total root length of each plant. Randomly
crop.
selected ten roots were weighed and their length was
measured by using Leaf Area Meter (Model 3100 of
measured and totaled.
The total root length was
LI-COR Inc., Lincoln, Nebraska, USA) and the LAI was
calculated by using the weight of the total roots at the
calculated by using the formula of Williams (1946). Leaf
same moisture level.
-1
Leaf area for the whole sampling unit was
Total root length (m hill ) =
Area Duration was determined with the formula of Power
(Length of sample roots (cm) × Weight of total roots (g))
et al. (1967) and the values were expressed in days.
/ Weight of sample roots (g). The volume of the root was
Specific Leaf Weight was calculated by adopting the
measured by volume displacement method (Bridgit and
formula of Pearce et al. (1969) and expressed in mg cm-2.
Potty, 2002) and expressed as root volume (cc) hill-1. The
The method as modified by Williams (1946) was
Root Mass Density (RMD) was measured by the procedure
employed for calculating the NAR on leaf dry weight basis
-3
of Pantuwan et al. (1997) and expressed as mg cm .
by applying the formula and expressed in mg per cm2 per
December, 2013
Effect of various micro irrigation treatments on growth and yield response of aerobic rice
day. Crop Growth Rate was estimated by the formula of -2
Vol. 22, No. 4 53
emitters. Constitutively, shallow rooting and sensitive
Watson (1956) and the values were expressed in g m per
responses of rhizogenesis and lateral root branching to
day.
unsaturated soils are the main reason for limited
Growth parameters were measured during
flowering stage of the crop.
adaptability to water-saving aerobic culture (Kato and
The yield and its components were recorded at the time of harvest.
Okami, 2011) by using the low discharge rate drippers.
The number of panicles, number of
The distribution of Root Mass Density (RMD) in the
spikelets, filled grain percentage, 1000 grain weight (Test
root system is an important indicator of the potential of
weight), and Harvest Index (HI) were recorded based on
water and nutrient uptake (Sharp and Davis, 1985).
the method of Yoshida et al. (1971). Harvesting of crop
Higher RMD was observed in treatment T3 (1.51) and
(grain) from each treatment and replication was made from
lower RMD observed in T10 (1.24) in DS 2011 (Table 2).
the net plot. After thrashing the grains, weight of the grain
Variation in lateral distance caused a change in root
was taken. Grain yield per hectare was calculated from the
distribution because of variation in water and nutrient
-1
mean plot yield and expressed in kg ha at 14% moisture
availability thus leading to the change in root mass and
content. Water productivity was calculated as the weight
density. Optimum lateral spacing showed better RMD
of grains produced per unit of water input (irrigation and
because of better water and nutrient application. Present
rainfall) as per the formula of Yang et al. (2005) and
results was also corroborated with previous observations
-1
expressed as g grain kg of water. The recorded data
of Matsuo et al. (2010) showing variation in availability
were subjected to statistical analysis in the Randomized
of nutrients changed the RMD in aerobic genotypes.
Block Design (RBD) using ANOVA Package (AGRES
The surface and subsurface drip irrigation methods along
version 7.01) following the method of Gomez and Gomez
with dripper discharge variability showed significant
(1984).
differences among the treatments. Increased RMD was
3
observed in the treatment T1 (1.64 mg cm-3) and lower in
Results and discussion
T10 (1.25 mg cm-3) in SS 2012.
Higher RMD was
The effects of micro irrigation treatment on root
observed in the SDI than the surface drip irrigation
parameters of aerobic rice showed a significant relation
treatments due to better availability of nutrients and water.
between the treatments.
Similar response was observed by Zotarelli et al. (2009)
Increased root length was -1
recorded in treatment T3 (50.7 m hill ) followed by T1 -1
-1
in tomato with SDI.
(50.2 m hill ) and lesser root length in T10 (41.8 m hill )
The root volume of aerobic rice showed a significant
at DS 2011(Table 1). The root length was increased in
difference with other treatments under varied micro
0.8 m lateral distance than 0.6 and 1.0 m lateral distances.
irrigation treatments. Significantly higher root volume
In SS 2012, the maximum root length was observed in
was observed in treatment T3 (49.9 cc hill-1) and least by
treatment T6 (34.0 m hill-1), followed closely by T1
T11 (26.2 cc hill-1) during DS 2011. In SS 2012, higher
(33.1 m hill-1) and the lowest root length was observed in
root volume was observed in T1 (26.6 cc hill-1 cc hill-1)
T10 (28.4 m hill-1).
Increase in root length under aerobic
and lower in T10 (22.7 cc hill-1). The micro irrigation
situation may be an added advantage to combat stress
system of rice recorded higher root activity as evident
under water limitation. Increased root length was further
from the presence of longer roots and higher root volume,
supported by the previous work of Richards (2008) in
which in turn increased drought tolerance for better
aerobic rice. The micro irrigation treatments on crop
nutrient and water uptake under SDI (Rajesh and
root length recorded more in SDI (T1) over surface
Thanunathan, 2003). During DS 2011, the root biomass
drippers with 30% excess water treatment (T6) and excess
of T3 treatment recorded significant differences among
potassium fertigated treatment (T9). By comparing
the micro irrigation treatments.
two-discharge variability in both experiments, 1.0 L h
-1
emitters showed increased root length than the 0.6 L h
-1
Higher root biomass -2
was noticed in T3 (209.2 g m ) with very less root biomass recorded in T10 (124.5 g m-2) (Table 2).
By
54
December, 2013
International Agricultural Engineering Journal
Vol. 22, No. 4
comparing T1, T3 and T5 treatments, increase in lateral
biomass in T10 (111.1 g m-2).
distance from 0.6m to 1.0 m caused reduction in water
was observed in treatment T1 than the conventional
availability to the root zone of crop.
aerobic rice treatment (T10).
Table 2
Increase in root biomass
under water stress might be considered as an adaptive
Effect of various micro irrigation treatments on root
mechanism for alleviating reduction in water uptake as a
parameters in aerobic rice, DS (2011) and SS (2012) Dry Season 2011
Increased root biomass
result of extra root growth. In SS 2012, the grain yield
Summer Season 2012
Treatments
was highly correlated with root biomass (0.963**),
RL
RMD
RV
RB
RL
RMD
RV
RB
T1
50.2
1.48
46.7
199.0
34.0
1.64
26.6
179.3
followed by productive tillers (0.952**) and water
T2
48.3
1.45
45.4
178.4
31.7
1.52
25.5
160.3
productivity (0.951**). Present study was in accordance
T3
50.7
1.51
49.9
209.2
31.8
1.56
25.4
168.8
T4
46.6
1.42
43.3
173.6
31.4
1.51
25.3
141.0
with the findings of Kato and Okami (2011) in aerobic
T5
44.6
1.38
42.4
158.0
30.8
1.45
25.2
130.9
T6
44.2
1.35
40.7
154.7
33.1
1.60
25.7
176.9
Plant growth attributes of aerobic rice under various
T7
48.5
1.47
46.3
184.4
32.4
1.39
25.7
174.8
T8
46.2
1.41
41.1
174.8
31.1
1.41
24.6
121.3
micro irrigation treatments were analyzed. Leaf Area
rice.
T9
44.4
1.35
34.5
153.7
30.2
1.34
24.3
114.8
Index is the efficiency of photosynthetic process and
T10
41.8
1.24
30.9
124.5
28.4
1.23
22.7
111.1
photosynthetic surface (Lockhart and Wiseman, 1988)
T11
43.1
1.29
26.2
173.9
Mean
46.3
1.39
40.7
171.3
31.5
1.47
25.1
147.9
SEd CD (P
