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EFFEC'l'S OF NIIBOGEN 1".cltTILISETI ON THE GROWi'H , D:i!.:VELOPT·:EHT

AND YIT.;LD OF l•iAIZE (~ l·~AYS L. ) .

A thesis

presented in partial fulfilment of the requirements

for the ciegree of

rt.ASTER. OF AGRICULTURAL SCI:C:NCE

in

PLANT SC IEllC E

at

!1.tASSSY UNIVERSITY

ERROL ROSS THOM

1974

ii

T ABL:S OF C or-:T1'NTS

LIST OF TABL:ES

LI S'l' OF FIGURES

v

vii

LIST OF PLATES

AC Ki\ OHLEDGEt~ENTS

s ur.::r.: .filly

viii

ix

xi

II~'TRODUC 'rI ON 1

2

3

3

4

C HAP'l'E.'R ONE REVIul OF LITERATURZ

1.1

1.2

1.3

1.5

1.6

Introduction

Sources of Nitrogen for Crop Plants

Aspects of l0iaize Gr0\·1th and Dry ;.;atter Accumulation

1.3.1 Growth and Distribution of Dry 1.;atter in Pl an t Par ts

1.3.2 Dry l1iatt er Distribution in the I·iature ?·!ai ~e

Plant

4

5 1.3 . 3 Ph otosynthes is and :Dr,y ;.:atter Production 6

1.3.4 Shoot-Root Re l a tions in i'0:aize 9

1. 3. 5 Black Layer and Physiological I1:aturi t:l in J0!aize 2.0

The J.:aL~e ]oot System 12

1.4.1 T11e Growth and Distribut ion of Maize Roots 13

1.4 . 2 The Effect of Environmen t on I•'.aize Root GroHth 15

1. 4. 3 Forms of I~i trogen Abs o!'bed by J.;aize Roo ts 20

Aspects of J.:aize Growth a!'ld l\ i t rcgen Accuraulation 21

l . 5 .1 I·:ai ze Growth and Nit rogen Uptake 21

1. 5.2 Plar1t Growth and Distributi on of Nitrogen in Plant Parts 23

1.5.3 Nitrogen Accumulation in the Grain at Maturity 23

Fertiliser Nitrogen and r.:aize Production

1.6.1 Nitrogen Fertil iser and Dry J1~atter Accumulation

24

25 1. 6.2 Fertiliser Uptake , Nitrogen Content and Yield 26

1.6.3 The Utilisation of Ni trogen in Protein Production in the t•iaize Plant 30

1.6.4 The Timing of Nitrogen Fertiliser Application 31

1.6.5 Nitrogen Fertiliser, Leaf Area and Dry Matter Yield 34

i·.6 .6 Effect of Nitrogen Fertiliser on the Components of Yield 35

1.6.7 Recovery of Fertiliser Nitrogen by Maize Plants 36

1.6.8 Method of Application of Fertiliser, Source of Nitrogen and Effect on Recovery

Nitrogen Deficiency Symptoms in 1°laize

37

39

CHAPTER Ti·TO

2.1 Introduction

KETIIODS A~ID ?·~ATIBIALS 41

42 2.1.1 F'~perimental Sito 42

2.1.2 ~perimental Layout 42

2.1. 3 His t ory of Plot Area and Cultural Operations 43 2. 2

2. 3

Experiment al Procedur es and Techniquco

2. 2.1 Intr oduction

2. 2. 2 Forrn of ~~i troeen Applied

2. ?. 3 Method of Fertiliser Application

2. 2. 4 Root Sampling Technique

2.2 . 5 Fiel d Observations

2. 2. 6 J<teasuremcnts on Harves ted Plants

2.2. 7 Per cen taee !h trogen Determi nation

Statistical Kethods

2.3 . 1 Preliminary Analysis of Data

2. 3. 2 The Analysis of Variance

2. 3. 3 Curve Fitting

CHAPTER THREE RESULTS

3. 1 General Descri;ition of the Gr owth and Development of the

46

46

46 47 47 48

49 52

53

53

53

53

57

Kaize Crop 58

3.2 Grain Yield and Plant Dry Katter Production (Final Harvest) 60

3. 3 Growth in Total Dry :·leic:-it and Component Parts 61

3. 3 . l Total Shoot Dry Weicht

3.3. 2 Dry :·:eight Changes in Veget a tive Components

3. 3. 3 Dry '..feight Changes in Reproductive Components

3. 4 Dry Matter Contents of Plant Component s

3. 5 Total Plant Nitrogen

3. 6 Concentration of Nit rogen in Plant Components

3. 7 Recovery of Fertiliser Nitrogen

3. 8 Chlorophyll Content

CHAPTER FOUR DISCUSSION

4 . 1 Experimenta l Results

4 . 1.1 Grain and Total Dry Matter Yields

4. 1.2 Dry f•latter Accumula tion and th~ Nitrogen Response Curve

4.1 . 3 Time of Fertiliser Application and Plant Response

4. 1.4 Ni trogen Fertiliser, Lea f Area Index and Longevity of the Photosynthetic Area

4. i.5 Total Dry Weight Changes in Other Component s

4. 1. 6 Nitrogen Uptake and Distribution

4. 1. 7 Nitrogen Deficiency Symptoms and Maize Production

62

63

69

71

72

78 81

82

83

84

84

84

88

92 95 99

104

4.1.8 Fertiliser Nitrogen and Its Efficiency of Utilisation

Conclusions

BIBLIOGRAPHY

APPENDICES

1 (a) Heather Data for the Experimental Period

l.V

106

107

Al

(b) Accumulated Effective Degree Days A2

2 Schedule of Operat ions A3

3 r.;ethod for Determining Chloro'phyll Content of r1iaize Leaves A6

4 ~:icro-Kjcldahl It.ethod for Determining Nitrogen Content of Plant Ifaterial A7

5 Analysis of Variance of Grain Dry ~/eight Per Plant and Total Dry Weight Per Hectare at Harvest 6 ( Physioloc;ical l·ia turi ty) A9

6 Growth in Total Dry Height Per Plant AlO

7 Comparison of Dry I·iatter Increment (y) with Time (x,days) (Linear form of Gompertz Curves) Al2

8 Analysis of Variance of Leaf Dry Heicht Per Plant a t Harvests 3, 4, 5 and 6 Al3

9(a) Sun1mary of Leaf Arca and LAI per Plant for the Main Factor Treatments (N rate) Al5

9(b) Analysis of Va riance of Sheath Area per Plant at Harvest 6 (Physiological ~:a turi ty) Al6

10 Analysis of Variance of Leaf Dry Matter Content and Stem Dry J1:atter Content at Harvest 6 and Harvests 3 and 4 Respectively Al7

11 Analysis of Variance of Total Shoot Nitrogen Yield per Hectare at Harvests 2, 4 and 6 Al9

12 Analysis of Variance of Leaf nitrogen Content per Plant at Harvests 2, 4 and 6 A21

13 Summary of Leaf, Stem and Root N Concentration per Plant for the Main Factor Treatment (N rate) A23

14 Analysis of Variance of Leaf Nitrogen Concentration per Plant at Harvest 4 A25

15 Summary of Grain Nitrogen Concentration per Plant at Harvests 4, 5 and 6 for the Main Factor Treatment (N rate) A26

Table

1.1

2. 1 2. 2

2. 3 3.1 3. 2 3. 3

3. 4

3. 6

3. 7

3. 8

3.10

3 . 11

3 . 12

3 . 13

3 .14

3. 15

3 .16

3 . 17

3 .18

3. 19

3 . 20

LI~T OF TABLES

Percentage of total shoot dry matter in different plant parts at maturity

Summary of Ni trogcn Fertiliser Treatments

Summary of Nonthly Rainfall Data

Plant Variables J.~easured at Each Harvest

Da.yG to 50% tasselline, cilking and physioloV.cal maturity

Daily air temperatures fo r December 1972 r.:ean dai ly air temperatures

Summary of total dry matter yields for grain and the whole shoot

Regression coefficients for total shoot dry weicht over t i me

Surrmary of lea f dr y weight per plant

Interaction effects beti·1een N rate and time of application for leaf dr y weight

Summary of she.ath area per plant

Interaction effects between N rate and time of application for sheath area

Summary of stem dry weight per plant

Root dry wei c:;ht per plant

Shoot to root r atios

S"Ll:"Tlrr.ary of 11husk" dry Height per plant

Summary of cob dry weicht per plant

Summa~y of componer.ts of b!'ain yield at physiological maturity

Yield of N in the 1·1hole shoot

Interaction effects between N rate and time of application for total N content

Nitrogen uptake per day

Interaction effects between N r ate and time of application for leaf N content

Interaction effects between N rate and time of application for stem N content

6

43

46

52 58

58

59

61

62

63

66

67 68

69 69 70

71 72

73 74

75

76

3 . 21 Root N content and yi eld 77

3 . 22 Interactio.!1 effects between N rate and time of application for "husk" N content 78

3 . 23 Interaction effects between N rate and time of application for stem N concentration 79

3. 24 Interaction effects between N rate and time of application for grain N concentration 81

3 . 25 Recovery of fertiliser N 81

Colour den:::1i ty after extraction in ethanol

E:::itirnated root dry weight data

Ratio of bI'i.i.in ni trogcn to stover nitrogen at physiological maturity

Paee 82

99

105

LIST OF FI GUrc::s

F'i {';ure

1

2

3

4

5

6

7 8

9

10

11

12

13

Experimental Layout

General Plant Growth and Development at :Sach Harvest

Total ~lant Production (excluding Roots) and Grain Yield

Comparison of Growth in Total Shoot Dry Weight Per Plant

Total Shoot Dry Weight and Percentage Distribution in Plant Parts

Re~Q.ti v.e Growth Rate of Leaves

Leaf Area Per Plant and LAI

Relative Growth Rate of Stem

Dry r.~atter Content (Fresh WeiGht Basis) of Shoot Cor.:ponents

Accumulation of Dry T·iatter and Xi trogen with Time Relative to the Final Harvest

Total Shoot Nitrogen Yield <md Percentage Distribution in Flan t Parts

Nitrogen Concentration in Leaf, Stem and Root

Nitrogen Concentration in Cob 1 "Husk" and Grain

43

59

60

62

64

64

64

66

72

73

73

79 80

Pl::i.te

1

2

3

4

5

6

7

8

9

LIST OF PLATGS

ShowinG the arrangement of irrication l aterals and whiGkers betwee n rows of maize plants

Showing the soil injector and its operation

Shoi·ri n;; root s ampli nr,- opera ti on; Gtecl frarr.e, container .:.rncl sample

Showin~ N deficiency symptoms in the lower portions of the plar,ts from a plot' receiving no N fertiliser

Showing normal colouration in the lower portions of plants from a. plot receiving G72 kg N/ha

Showi nc lower l eaf and stem portions of individual plants rcceivinr; 672 kg IT/ha (LBS ) and no N fertiliser (HHS)

ShowinG' individua) pl ants receiving 672 kc N/ha (LHS) and no N fertil:iGer (nHS)

Showing individual plants receiving 168 kg 11/ha (LHS) and no N fertiliser (RHS )

Showing indiviciual plants receiving 84 kg r;/ha (LHS) and no N fertiliser (RHS)

45 45

48

59

59

59

59

59

59

viii

ix

ACKNOWLEDGE! .. ~"SNTS

If is my pleasure to acknowledge the constant interest,

encouragement and gi;.idance that I received from my supervisor

Professor B.R. ilatkin (Agronomy Department, Massey University ), during

the course of this project. His assistance and helpful criticism in

the preparation of this manuscri pt was also much appreciated.

To Mr . G.O. Fdmeades (presently at the University of Guelph,

Ontario, Canada) I extend my thanks for his interest and help in the

initial planning of this project.

I am indebted to Mr . J .s. Wheeler (former Dairy Farms Supervisor)

for permission to use land at his disposal and for the latitude given

in the choice of a site to conduct this experiment.

The respective donations of seed and insecticide by Thomas Corson

and Son, Ltd., Gisborne and Neill , Cropper and Co., Ltd., were

gratefully received.

For their encourage~ent and help in the computer analyses and time

willingly given in discussion and interpretation of results I wish to

t hank r.:r . A.C. P. Chu and £.:r. I.L. Gordon . I an1 grateful to I·'.r . A. G.

Robertson for helpful advice, the pr ovi si on of the soil injector, and

for taking t he photograph of the root sampling operation . Tta.~ks is

due to liiss R. K. F..d.monds for competent technical assistance during the

Kjeldahl analyses and for drawing Figure 2, and to I·ir • .s.rr,. Badger for

designing and constructing the steel frame used in the root sampling

operation.

I wish to extend my thanks to Dr. J.A. Pollok (Soil Science

Department, Massey University) for conducting a detailed study of the

soil in the plot area and to all other members of the Agronomy and

Soil Science Departments who offered helpful advice during the course

of this project.

I wish to gratefully acknowledge the interest and advice of

Mr. P.R. Ball (Grasslands Division, D.S.I.R., Palmerston North) that

was willingly given on numerous occasions throughout this study and

for permission to use unpublished data. I am grateful to the staff of

the Analytical Laboratory at Grasslands Division, D.S.I.R., Palmerston

North for carrying out total N' determinations on soil samples. I am

indebted to Professor R.L. Earle (Biotechnology Department, Massey

University) for providing suitable laboratory faoili ties for the

Kjeldahl analyses.

I would like to express my appreciation of the prompt and

efficient service received at all times from the staffs of the

:r.:assey University and D. S . I . R. Libraries .

x

I·am particularly grateful to my friends and members of my family

who willingly gave of their time at critical stages of the field work .

I wish to express my gratitude to 1-lrs . P . O. ~·'.artis for her careful

and prompt typing of the draft and final .copy of this thesis and to

the staff of the Viassey University Printery for the production of the

figures.

·Th~ unlimited assistance and understanding of my family was of

immense value in eiving me the assurance necessary to complete this

project .

SUJ.'ITIIARY

The respon::;e of a commercial maize cultivar ( PX610). to nitrogen

fertiliser (urea) was studied . Four l evels of nitrocen viz. 84 , 168,

336 2.nd 672 kc/ha were applied over three different growth stages as

follows: (i) all at planting; (ii) tat planting, ~at 6 weeks

growth ; (iii) -} at planting, 1 at 6 Hecks GI'OWth 1 ~ at so;: Silking.

'l'he plants were crown at a population of 96,900/ha and water was

continuously applied to the crop throur,h a trickle irrii:;ation system .

A.L

'l'otLt1. · and cor.iponcnt plant responses were determined on several

occasions throuchout the experimental period to physioloGical maturity .

Nitrocen l evels and distribution within the plant were also measured.

The yields of grain (11,000-14,000 kg/ha) and total plant dry

matter (24,000-29,000 kg/ha) recorded at physiological maturity were

hi gh . However, no significant plant dry weight responses to different

rates and times of nitrogen fertiliser application were detected.

Nevertheless, critical analysis of these responses did show that the

rate at which plants reached their 1.1axir.rnm dr,y matter production

(upper asymptote) was c;reatest in the treatments receivi ng intermediate

levels (168 and 336 kg/ha) of nitrogen fertiliser .

Significant differences ivere recorded in terms of the nitrogen

content of the plant in the res pons e to t he nitrogen applied . Uptake

of nitrogen increased with nitrogen rate and the concentration of

nitrogen in the grain and most other plant components, increased with

higher rates of nitrogen fertiliser . During early growth there was a

precocious accumulation of nitrogen in the leaves . Substantial losses

of dry weight and nitrogen from non- grain components, ~specially the ·

stems, occurred over the period of rapid grain filling. These losses

were. noticeable at an earlier stage in plants showing visual nitrogen

deficiency symptoms (those receiving no nitrogen fertilis er and 84 kg

N/ha). However, these plants appeared to make more efficient use of

available nitrogen in grain production than plants receiving higher

rates of nitrogen.