biology and management of fimbristylis miliacea (l.)...

BIOLOGY AND MANAGEMENT OF FIMBRISTYLIS MILIACEA (L.) VAHL

By

MAHFUZA BEGUM

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,

in Fulfillment of the Requirement for the Degree of Doctor of Philosophy

September 2006

ii

Dedicated

To

My Father, Memory of My Mother and Niece Moonmoon

And

My Husband Md. Zahid Iqbal, Kids Promee and Alvee,

with Whom I experience the Joys and

Responsibilities of Commitment Each Day

iii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment

of the requirement for the degree of Doctor of Philosophy

BIOLOGY AND MANAGEMENT OF FIMBRISTYLIS MILIACEA (L.) VAHL

By

MAHFUZA BEGUM

September 2006

Chairman: Associate Professor Abdul Shukor Juraimi, PhD

Faculty: Agriculture

Most experiments were carried out in a glasshouse at Universiti Putra Malaysia,

while the field survey was conducted in ricefields in the Muda area, Kedah. This

study was initiated during March 2003 and ended on November 2005. The objectives

of the study were to investigate the prevalence of F. miliacea in ricefields both above

ground as well as in the soil seedbank, its emergence behaviour, life cycle, life table,

competitive ability with rice, and its management.

Results from field survey revealed that F. miliacea was the fifth most prevalent

weed out of 35 species in the Muda area with 46 -52% fields infested and widely

distributed over the four districts of Muda with infestation rating scores from traces –

30% weed coverage. Out of 20 weed species identified in the soil seedbank, F.

miliacea was the most abundant with 66.07% of total seed reserve (equivalent to

750.84 million seeds/ha), of which 55% emerged in soils incubated in trays (411.48

million seedlings/ha), 8% germinated in incubation tests in petridishes (61.59 million

seedlings/ha), while 37% or the equivalent of 277.77 million seeds/ha remained

dormant or dead.

iv

Fimbristylis miliacea exhibited high emergence (44.38%) from surface seeding.

Seeds sown at 0.5 cm depth had significantly reduced emergence (13%) and no

seedlings emerged from 1.0 cm soil depth. For flooding durations of 7, 14 and 21

days, per cent emergence and dry matter production were higher under saturated

conditions than at 5 and 10 cm flooding depths. A flooding duration of 14 days or

more and in flooding depth up to 10 cm showed a clear trend in reduced emergence

and dry matter production of Fimbristylis miliacea.

During the cropping season (4 month period) each F. miliacea plant produced on

average of 2.3 tillers/plant and a total of 134 inflorescences, with 84

inflorescences/plant ripening within this period. Each inflorescence comprised of 48

spikelets with 511 seeds and matured after 3 weeks of emergence. Total seeds/plant

and 1000 seed weight were 42,275 and 0.035 g, respectively. Time required for seed

ripening was 76 days after emergence. This species had three important growth

stages: a slow growth stage during the first 4 week after emergence (WAE); a rapid

growth stage from 4-9 WAE; and finally, a maximum growth stage from 9-17 WAE.

The life table study showed that plants establishing from every 100 seeds of F.

miliacea plants can reproduce 287,722 seeds with nitrogen treatment, which was

1.66 fold greater than without nitrogen. High death rates in F. miliacea among young

seedlings indicated a Deevey Type III survivorship curve. Early emerging cohorts

had greater survivorship and contributed most extensively to the next generation by

producing more than 90% seeds.

The interaction between weed density and nitrogen (N) fertilization had a

pronounced influence on rice yield. At low weed densities of up to 500 plants/m2,

v

rice yields increased with higher N fertilization. On the other hand, at the higher

weed density of 1000 plants/m2, increasing N fertilization to 170 kg/ha had no

significant effect on yield. However, rice yield at this level of N fertilization with the

lowest weed density of 250 plants/m2, was similar to the weed-free treatment. Based

on the predicted Logistic and Gompertz response curves the critical period for

controlling F. miliacea in direct-seeded rice was between 14 – 28 days after sowing.

Flooding and use of herbicides are two important weed control methods in direct-

seeded rice. Flooding had a major suppressive effect on stand establishment and

growth of F. miliacea, especially during the early growth stages (7 and 14 DAS).

Delayed flooding at 21 and 28 DAS required a 10 cm flooding depth for effective

control. All tested herbicides were effective in controlling F. miliacea, but the

herbicides bensulfuron and fentrazamide increased grain yield by more than 80%

compared to the unweeded treatment and were comparable to the weed-free (hand-

weeded) treatment.

vi

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk ijazah Doktor Falsafah

BIOLOGI DAN PENGURUSAN FIMBRISTYLIS MILIACEA (L.) VAHL

Oleh

MAHFUZA BEGUM

September 2006

Pengerusi: Profesor Madya Abdul Shukor Juraimi, PhD

Fakulti: Pertanian

Sebahagian besar eksperimen telah dijalankan di rumah kaca, Universiti Putra

Malaysia, sementara survei rumpai dijalankan di kawasan jelapang padi, Muda,

Kedah. Kajian bermula pada bulan Mac 2003 dan berakhir pada bulan November

2005. Objektif kajian ialah untuk menentukan tahap dominan Fimbristylis miliacea

di kawasan Muda di samping menentukan tahap bank benihnya dalam tanah, tabiat

kemunculannya, kitar hidup, jadual hayat, keupayaan daya saing dengan tanaman

padi, dan juga pengurusannya.

Keputusan survei mendapati F. miliacea adalah rumpai yang ke lima terbanyak

daripada 35 spesies yang direkodkan di kawasan Muda dengan 46-52% kawasan

didapati diinfestasi, dan mempunyai taburan meluas meliputi empat daerah di Muda

dengan skor infestasi bermula dengan sangat sedikit (beberapa pokok) sehingga 30%

litupan. Daripada 20 spesies rumpai yang dikenalpasti daripada bank biji benih

dalam tanah, F. miliacea adalah yang paling banyak iaitu 66.07% (750.84 juta biji

benih/ha) daripada keseluruhan yang tersimpan, dengan 55% (411.48 juta anak

benih/ha) muncul ketika ujian dalam kotak percambahan, 8% (61.59 juta anak

vii

benih/ha) bercambah dalam piring petri dan 37% (277.77 juta biji benih/ha) dorman

atau mati.

F. miliacea menunjukkan kemunculan yang tinggi (44.38%) daripada rawatan

penanaman di permukaan. Kemunculan biji benih yang ditabur pada kedalaman 0.5

cm menurun dengan bererti kepada 13% dan tiada benih muncul pada kedalaman

tanah 1.0 cm. Untuk tempoh pembanjiran 7, 14 dan 21 hari, peratus kemunculan dan

berat kering adalah tinggi pada kedaan tanah tepu air berbanding dalam kedaan air

bertakung sedalam 5 dan 10 cm. Pembanjiran selama 14 hari atau lebih dan

kedalaman pembanjiran sehingga 10 cm menunjukkan polar penurunan kemunculan

dan penghasilan berat kering F. miliacea.

Ketika musim penanaman padi (tempoh 4 bulan) setiap pohon F. miliacea

menghasilkan purata 2.3 anak bilah/pokok dan 134 infloresen, dengan 84

infloresen/pokok yang matang semasa tempoh tersebut. setiap infloresen

mengandungi 48 spika dengan 511 biji benih dan matang 3 minggu selepas muncul.

Jumlah bilangan biji benih/pokok dan berat 1000 biji benih adalah masing-masing

42275 biji dan 0.035 g. Masa yang diperlukan untuk benih masak adalah 76 hari

selepas muncul. Spesies ini mempunyai tiga peringkat pertumbuhan : peringkat

pertumbuhan lambat, 4 minggu pertama selepas muncul (MSM); peringkat

pertumbuhan cepat, 4-9 MSM; dan peringkat pertumbuhan maksimum, 9-17 MSM.

Jadual hayat menunjukkan pokok yang tumbuh daripada setiap 100 biji benih boleh

menghasilkan 287,722 biji dengan penambahan nitrogen, 1.66 kali ganda lebih

daripada tanpa nitrogen. Kadar kematian yang tinggi dikalangan anak benih F.

miliacea menandakan kemandirian kelok “Deevey Type III”. Kohort yang muncul

viii

awal mempunyai peluang hidup yang besar dengan menghasilkan 90% benih untuk

generasi seterusnya.

Interaksi antara kepadatan rumpai dan pembajaan N mempunyai pengaruh yang kuat

terhadap hasil padi. Pada kepadatan rendah sehingga 500 pokok/m2, hasil padi

bertambah dengan pembajaan N. Sebaliknya pada kepadatan tinggi 1000 pokok/m2,

penambahan pembajaan N sehingga 170 kg/ha tidak menunjukkan kesan bermanfaat

terhadap hasil padi. Walau bagaimanapun pada paras pembajaan N ini, hasil padi

pada kepadatan rumpai yang terendah 250 pokok/m2, adalah sama dengan rawatan

bebas rumpai. Berdasarkan peramalan kelok rangsang Logistic dan Gompertz,

tempoh kritikal untuk kawalan F. miliacea adalah antara 14 – 28 hari lepas tabur.

Pembanjiran dan penggunaan racun herba adalah dua keadah penting kawalan

penting di kawasan tanaman padi tabur terus. Pembanjiran menunjukkan kesan

kawalan yang kuat terhadap penapakan dan pertumbuhan F. miliacea, terutamanya

ketika peringkat awal tanaman [(7 dan 14 hari lepas tanam (HLT)]. Menangguhkan

rawatan pembanjiran kepada 21 dan 28 HLT memerlukan 10 cm kedalaman air

untuk kawalan yang berkesan. Semua racun rumpai diguna dapat mengawal F.

miliacea dengan berkesan, tetapi rawatan bensulfuron dan fentrazamide dapat

meningkatkan hasil padi melebehi 80% berbanding rawatan tanpa kawalan rumpai,

dan setara dengan rawatan bebas daripada rumpai.

ix

ACKNOWLEDGEMENTS

Praise to Almighty Allah for His blessings, kindness and giving me proper guidance,

strength, and will to complete this study.

I wish to express my heartfelt gratitude, indebtedness, and deep sense of respect to

Dr. Abdul Shukor Juraimi, the Chairman of the Supervisory Committee for his

sincere support, guidance, constant encouragement, invaluable suggestions and

generous help throughout the study period. I am much indebted and grateful to

Associate Professor Dr. Rajan Amartalingam, Associate Professor Dr. Syed Omar

Bin Syed Rastan, and Dr. Azmi Bin Man, members of the supervisory committee, for

their encouragement, constructive suggestions and guidance in formulation and

execution of the research projects and critical review of the manuscript.

I, thankfully acknowledge the assistance of TWOWS (Third World Organization for

Women in Science) for financial support and facilitating my study in Malaysia, and

Universiti Putra Malaysia for providing research facilities under the Intensification of

Research priority Areas No. 01-02-04-0778-PR0068/05-05. Furthermore, I am

grateful to the administrative authority of Bangladesh Agricultural University (BAU)

for providing deputation and all kinds of help to accomplish my degree.

I feel proud to express my sincere appreciation and indebtedness to all of my

teachers of the Department of Agronomy, BAU, for their cooperation,

encouragement and valuable suggestions. I would like to thank Hj Yasir Isman for

his assistance in glasshouse and field works. I also wish to express my appreciation

to all of my post graduate friends and well wishers.

x

I respectfully acknowledge the blessings and good wishes of my father, sisters,

brothers, brother-in-law, sister-in-law and relatives. I am especially grateful to my

sister Dr. Salina Begum and mother-in-law, who, despite their heavy professional

commitment and old age had provided lots of encouragement and moral support and

looked after my children in my absence. Special gratitude must go to my daughter

Sadia Nowrin Promee and son Iqbal Maheer Alvee who have faced difficult times

during my study period. Without their love, great sacrifice, and support this study

would not have been possible.

Finally, and above all my husband Md Zahid Iqbal deserves a lot of thanks and

appreciation not only for his love and care, but also for bearing the burden and

responsibilities of taking care of our children in my absence, in addition, later on, for

active cooperation and support to conduct experiments and encouragement a higher

degree.

I would like to express my humble apology to those persons, who helped me but may

not find their names in my narration here.

xi

I certify that an Examination Committee has met on 18 September 2006 to conduct

the final examination of Mahfuza Begum on her Doctor of Philosophy thesis entitled

“Biology and Management of Fimbristylis miliacea (L.) Vahl” in accordance with

Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian

Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the

candidate be awarded the relevant degree. Members of the Examination Committee

are as follows:

Mohd Razi Ismail, PhD

Professor

Faculty of Agriculture

Universiti Putra Malaysia

(Chairman)

Rosli Mohamad, PhD Professor



(Internal Examiner)

Anuar Abdul Rahim, PhD

Associate Professor



(Internal Examiner)

Mahsor Mansor, PhD

Professor

School of Biological Sciences

Universiti Sains Malaysia

(External Examiner)

________________________________

HASANAH MOHD GHAZALI, PhD

Professor/Deputy Dean

School of Graduate Studies


Date:

xii

This thesis submitted to the Senate of Universiti Putra Malaysia and has been

accepted as fulfilment of the requirement for the degree of Doctor of Philosophy.

The members of the Supervisory Committee are as follows:

Abdul Shukor Juraimi, PhD

Associate Professor



(Chairman)

Rajan Amartalingam, PhD

Associate Professor



(Member)

Syed Omar Syed Rastan, PhD

Associate Professor



(Member)

Azmi Man, PhD

MARDI

Kepala Batas, Pulau Pinang

(Member)

_______________________

AINI IDERIS, PhD

Professor/Deputy Dean

School of Graduate Studies


Date:

xiii

DECLARATION

I hereby declare that the thesis is based on my original work except for quotations

and citations which have been duly acknowledged. I also declare it has not been

previously or concurrently submitted for any other degree at UPM or other

institutions.

____________________

MAHFUZA BEGUM

Date: 18 October 2006

xiv

TABLE OF CONTENTS

Page

DEDICATION ii

ABSTRACT iii

ABSTRAK vi

ACKNOWLEDGEMENTS ix

APPROVAL xi

DECLARATION xiii

LIST OF TABLES xvii

LIST OF FIGURES xix

CHAPTER

1 INTRODUCTION

1.1

2 LITERATURE REVIEW 2.1

2.1 Fimbristylis miliacea (L.) Vahl 2.1

2.1.1 Introduction 2.1

2.1.2 Geographical Distribution 2.2

2.1.3 Taxonomic Description 2.3

2.1.4 Morphology 2.4

2.1.5 Physiology 2.5

2.1.6 Reproduction 2.5

2.1.7 Ecological Habitat 2.6

2.1.8 Agricultural and Economic Importance 2.6

2.2 Ecology of Weeds in Ricefields 2.7

2.2.1 Weed Communities 2.7

2.2.2 Shift in Weed Species Composition 2.9

2.2.3 Status of F. miliacea in Ricefields 2.10

2.3 Soil Seedbank 2.14

2.3.1 Number of Seeds in the Seedbank 2.14

2.3.2 Species Composition in the Seedbank 2.15

2.3.3 Fate of Seeds in the Seedbank 2.16

2.3.4 Emergence Patterns 2.17

2.3.5 Prediction of Potential Above-ground Weed

flora

2.18

2.4 Weed Seedling Emergence 2.19

2.4.1 Soil Depth and Seedling Emergence 2.19

2.4.2 Flooding and Seedling Emergence 2.21

2.5 Life Cycle of Weeds 2.22

2.6 Life Table of Weeds 2.24

2.6.1 Emergence Cohort 2.24

2.6.2 Weed Survivorship 2.25

2.6.3 Reproductive Capacity of Weeds 2.26

2.7 Weed-Crop Competition 2.28

2.7.1 Competition 2.28

2.7.2 Weed-Crop Density 2.29

xv

2.7.3 Effect of Nitrogen on Competition 2.30

2.8 Critical Period for Competition 2.32

2.9 Management of F. miliacea in Ricefields 2.35

2.9.1 Management by Flooding 2.35

2.9.2 Management by Herbicides 2.37

3 OCCURRENCE OF Fimbristylis miliacea (L.) Vahl IN

MUDA RICEFIELD AREA

3.1

3.1 SURVEY ON WEEDS OF RICE FIELDS IN MUDA

AREA

3.1

3.1.1 INTRODUCTION 3.1

3.1.2 MATERIALS AND METHODS 3.3

3.1.3 RESULTS AND DISCUSSION 3.5

3.1.4 CONCLUSION 3.15

3.2 SEEDBANK STUDY ON RICEFIELD SOILS FROM

THE MUDA AREA

3.16




3.2.4 CONCLUSION

3.32

4 EMERGENCE CHARACTERISTICS OF Fimbristylis

miliacea (L.) Vahl

4.1

4.1 SOWING DEPTH ON SEEDLING EMERGENCE 4.1





4.2 FLOODING DEPTH AND DURATION ON

SEEDLING EMERGENCE

4.4





5 LIFE CYCLE AND LIFE TABLE STUDY OF

Fimbristylis miliacea (L.) Vahl

5.1

5.1 LIFE CYCLE STUDY 5.1





5.2 LIFE TABLE STUDY 5.12




5.2.4 CONCLUSION

5.23

xvi

6 COMPETITION STUDIES BETWEEN RICE AND


6.1

6.1 COMPETITION IN RELATION TO NITROGEN

LEVELS AND WEED DENSITY

6.1





6.2 CRITICAL PERIOD OF COMPETITION 6.12




6.2.4 CONCLUSION

6.24

7 CULTURAL AND CHEMICAL CONTROL OF


7.1

7.1 TIME AND DEPTH OF FLOODING ON SURVIVAL

AND GROWTH OF Fimbristylis miliacea

7.1





7.2 EFFICACY OF SELECTED HERBICIDES FOR

THE CONTROL OF Fimbristylis miliacea

7.6




7.2.4 CONCLUSION

7.18

8 GENERAL CONCLUSIONS, RECOMMENDATIONS

AND SUGGESTIONS FOR FUTURE RESEARCH

8.1

8.1 GENERAL CONCLUSIONS 8.1

8.2 RECOMMENDATIONS 8.4

8.3 SUGGESTIONS FOR FUTURE RESEARCH 8.5

REFERENCES R.1

APPENDICES A.1

BIODATA OF THE AUTHOR B.1

xvii

LIST OF TABLES

Table Page

3.1 The number of weed species observed within the blocks in the

Muda area

3.34

3.2 Distribution of weed species based on family affiliation and weed

type in the four districts of Muda rice granary area

3.35

3.3 Occurrence of weed species in the 4 districts of Muda rice granary

area (% of fields infested)

3.36

3.4 Sorenson’s index of similarity in weed species among the four

districts in the Muda rice granary area

3.36

3.5 The occurrence at six levels of frequency for 8 or 9 most abundant

weed species in direct-seeded rice in the four districts in Muda

area

3.37

3.6 Occurrence of weed species based on per cent-infested fields out

of 579 fields surveyed in Muda rice granary

3.38

3.7 Number of ricefields infested by each species at each of six levels

of occurrence (Total fields surveyed = 579)

3.39

3.8 Total seedling emergence of 14 common weed species in soils

from Muda ricefields

3.40

3.9 Total number of ungerminated seed reserves of 13 common weed

species in soils from Muda ricefields after the 12 month incubation

period

3.41

3.10 Mean weed seedbank of 20 taxa in ricefield soils in Muda area

3.42

3.11 Frequency of occurrence of individual weed species in the soil

seedbank

3.42

3.12 Total emerged seedlings, ungerminated seeds and total seed

reserves of F. miliacea at 24 sampling sites

3.43

4.1 Emergence percentage of F. miliacea at different depths and

duration of flooding

4.10

5.1 Growth pattern of F. miliacea plant during the 4 month period

after sowing

5.25

5.2 Approximate time required for seedling emergence, leaf, tiller and

inflorescence formation and inflorescence ripening

5.26

xviii

5.3 Influence of nitrogen fertilizer on % emergence and

seeds/inflorescence (Average value of 4 cohorts)

5.27

5.4 Differences between cohorts on % emergence and

seeds/inflorescence (Average value of 4 cohorts)

5.27

5.5 Effect of nitrogen fertilizer on % emergence, % survival, total

tillers, inflorescence/pot, seeds/pot and dry matter/pot of F.

miliacea (Cumulative value of 4 cohorts)

5.27

6.1 Vegetative growth and yield contributing characters influenced by

weed density

6.25

6.2 Vegetative growth and yield contributing characters influenced by

N levels

6.25

6.3 Plant height and yield components of rice as affected by different

periods of F. miliacea competition

6.26

6.4 Rice straw biomass, weed dry matter, grain yield and % grain

yield loss as affected by different period of F. miliacea

competition

6.27

6.5 Maximum weed-interference and minimum weed-free period in

rice calculated from regression equation for three predetermined

levels of crop yield loss

6.27

7.1 Herbicide treatments used to control of Fimbristylis miliacea 7.20

7.2 Effect of herbicides on weed control, crop toxicity rating at 21

DAA, chlorophyll content at panicle initiation and rice plant

height at harvest

7.20

7.3 Yield contributing characters of rice as affected by weed control

treatment

7.21

7.4 Production of straw and grain yield due to weed control treatments 7.21

xix

LIST OF FIGURES

Figure Page

2.1 Fimbristylis miliacea (L.) Vahl. a spikelet; b. glume, dorsal view

(opened); c. flower; d. nut (Adopted from Soerjani et al., 1987)

2.45

2.2 Ricefield infested by F. miliacea (L.) Vahl in Muda area

2.46

2.3 The seed bank cycle (inputs to the seed bank are shown with black

arrows and losses in white arrows, modified from Anil Shrestha,

2001)

2.46

2.4 Scheme illustrating the life cycle of an annual flowering plant,

adopted from Grim (1979)

2.47

3.1 The Four Districts in the Muda area in Peninsular Malaysia where

the survey was conducted

3.44

3.2 Weed communities in different districts of Muda rice granary area

3.45

3.3 Weed distribution by communities in the Muda rice granary area

3.45

3.4 Severity of F. miliacea infestation in five farm blocks in District-I

3.46

3.5 Severity of F. miliacea infestation in nine farm blocks in District-

II

3.46

3.6 Severity of F. miliacea infestation in six farm blocks in District-III

3.47

3.7 Severity of F. miliacea infestation in seven farm blocks in

District- IV

3.47

3.8 Soil sampling sites in the Muda area in Peninsular Malaysia

3.48

3.9 Number of germinable seeds, remaining seeds and total seed

reserve in soil samples from all sites in Muda ricefields (AB- Alor

Belat; BT- Batu-17; SD - Sungai Daun; ST - Simpang Tiga)

3.49

3.10 Total number of seedlings and remaining seeds as a percentage of

the total seeds in the top 10 cm of soil in Muda ricefields (AB –

Alor Belat; BT – Batu-17; SD – Sungai Daun; ST – Simpan Tiga)

3.50

3.11 Relative proportion of germinable seeds of five most important

weed species in the soil seedbank of Muda ricefields

3.51

3.12 Relative proportion of ungerminated seed reserves of five most

important weed species in the soil seedbank in Muda ricefields

3.51

xx

3.13 Relative proportion of total soil seedbank of five most important

weed species in Muda ricefields

3.51

3.14 Periodic and cumulative weed seedling emergence in Muda

ricefield soils during the12 month period

3.52

3.15 Number of weed seedlings emergence in soil samples from all

sites in Muda ricefields (AB- Alor Belat; BT- Batu-17; SD -

Sungai Daun; ST - Simpang Tiga)

3.53

3.16 Temporal variation in F. miliacea seedling emergence relative to

other species during the 12 month incubation of the soil samples

from Muda ricefields (mean of all locations)

3.54

3.17 Cumulative emergence of F. miliacea seedlings relative to other

species during the 12 month incubation of the soil samples from

Muda ricefields (mean of all locations)

3.54

3.18 Mean number and percentage F. miliacea seedbank in Muda area.

3.55

4.1 Effect of sowing depth on cumulative emergence of F. miliacea

after 7, 14, 21 and 28 days of sowing (Error bar denotes ± SE)

4.10

4.2 Effect of flooding depth and duration on dry matter of F. miliacea

(Means within flooding durations with same alphabets are not

significantly different at P ≥ 0.05 (Tukeys Test))

4.11

5.1 Weekly measured plant height and inflorescence number of F.

miliacea (Means within week after emergence (WAE) with same

alphabets are not significantly different at P ≥ 0.05 (Tukeys Test))

5.28

5.2 Relationship between tiller number and inflorescence number

5.28

5.3 Life cycle of Fimbristylis miliacea (L.) Vahl

5.29

5.4 Survivorship curves of F. miliacea (Means within cohorts with

same alphabets are not significantly different at P ≥ 0.05 (Tukeys

Test)

5.30

5.5 Cohorts’ survivorship curves of F. miliacea (with nitrogen

application)

5.30

5.6 Cohorts’ survivorship curves of F. miliacea (without nitrogen

application)

5.31

5.7 Fecundity (Inflorescences/plant) of successive plants of F.

miliacea over a four month period (Means within cohorts with

same alphabets are not significantly different at P ≥ 0.05 (Tukeys

Test))

5.31

xxi

5.8 Fecundity (seeds/plant) of successive plants of F. miliacea over a

four month periods (Means within cohorts with same alphabets are

not significantly different at P ≥ 0.05 (Tukeys Test))

5.32

5.9 Contribution of successive cohorts of F. miliacea to total seed

production (With nitrogen application)

5.32

5.10 Contribution of successive cohorts of F. miliacea to total seed

production (Without nitrogen application)

5.33

5.11 Fecundity (seeds/pot) of successive plants of F. miliacea over a

four month period (Means within cohorts with same alphabets are

not significantly different at P ≥ 0.05 (Tukeys Test))

5.33

5.12 The flow chart of life table of F. miliacea which was treated with

nitrogen 100 kg / ha (A) and without nitrogen (B)

5.34

6.1 Rice plant height response to N treatment for all weed density

levels (Means within N levels with same alphabets are not


6.28

6.2 Rice straw biomass in response to N treatment for all weed density



6.28

6.3 Weed dry matter content in response to N treatment for all weed

density levels (Means within N levels with same alphabets are not


6.29

6.4 Nitrogen uptake by the weed in response to N treatment for all

weed density levels (Means within N levels with same alphabets

are not significantly different at P ≥ 0.05 (Tukeys Test))

6.29

6.5 Rice productive tillers variation to N treatment for all weed

density levels (Means within N levels with same alphabets are not


6.30

6.6 Grains/panicle variation to N treatment for all weed density levels

(Means within N levels with same alphabets are not significantly

different at P ≥ 0.05 (Tukeys Test))

6.30

6.7 Grain yield variation due to N treatment for all weed density



6.31

6.8 Regression of grain yield on weed dry matter at 100 kg/ha N level

6.31

6.9 Regression of grain yield on weed dry matter at 170 kg/ha N level

6.32

xxii

6.10 Treatments tested for critical period of competition between rice

and Fimbristylis miliacea

6.32

6.11 Regression of grain yield on weed dry matter

6.33

6.12 Effect of different periods of weed competition on rice grain

yields. Gompertz equation RY = -162.3648 + 258.6611* exp(-

exp(x -15.1943)/8.1087)), R2 = 0.97; Logistic equation RY =

51.8034 + 47.5228/ (1+ (x/45.8380) 1.9916

, R2 = 0.99

6.33

7.1 Effect of time and depth of flooding on survival of F. miliacea

(Means within columns with same alphabets are not significantly


7.22

7.2 Effect of time and depth of flooding on plant height of F. miliacea



7.22

7.3 Effect of time and depth of flooding on root length of F. miliacea



7.23

7.4 Effect of time and depth of flooding on number of leaves of F.

miliacea (Means within columns with same alphabets are not


7.23

7.5 Effect of time and depth of flooding on dry weight (g/pot) of F.

miliacea (Means within columns with same alphabets are not


7.24

7.6 Relationship between productive tillers and leaf chlorophyll

content

7.24

biology and management of fimbristylis miliacea (l.)...

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