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Dec 1, 2013 - Abstract: Drip irrigation studies were conducted in aerobic rice during Dry Season ... Email: [email protected]. Mochizuki, 2009).
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

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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

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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

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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