Copyright is owned by the Author of the thesis. Permission is given for
a copy to be downloaded by an individual for the purpose of research and
private study only. The thesis may not be reproduced elsewhere without
the permission of the Author.
AN INV?.JSTIGA TION INTO THE
TECHNIQUES OF DIRECT DRILLING SEEDS INTO UNDISTURBED, SPRAYED PASTURE.
A Thesis presented in partial fulfillment of the requirements for the degree of
Doctor of Philosophy at Massey University, Palmerston North
New Zealand by
Christopher John Baker March 1976
An i nvestigation i nto the te chniquesof direct dri l li ng s eeds into undisturb ed sprayed pasture
C.J. Bake r
A!i�M!..t
Meth ods of evaluating t he t echniques and e quipment us ed f or direc t dri lli ng of s eeds int o unti l led soi ls were revi ewed and deve loped. Fi e ld tes ts were use d to high ligh t seed ling es tablishment prob lems and wer e comp lim en ted by a t i l lage b i n technique which sought to i s o late variab les such as c limate, soil type and s o i l mois ture regime. The t i l lage bin technique i nvo lved c o l lecting half-tonne undisturbed b locks of turf in open ended s t e e l bins using a special turf cutting machine. The se t i l lage bins were s ubjec t ed to a common c limat e and moi s ture s upply by p lacing them bene at h transparent rain canopi e s and app lying water artificially . Dri l ling uti lized a suppo r t bed on whi ch s evera l b ins were p laced end to end and whi ch was s tradd led by a moving gantry and too l t es t ing apparatus operating
on rai ls alongs id e . This faci lity allowed c lo se visual apprais al to b e made of the ac tion of coulters and s e ed depo sition and was opera ted at speeds which were infinite ly var iab le, within limits. See d metering was preci sely c ontro l le d and s e le cted coult er f orc es and s oi l physical properties were
measure d wi t h the apparatus. Turf b lo cks , in their tillage bins, were re tur·11erJ t o the ra in protection cano pi e s after dri lling for p lant response studios.
Soil c over over the seed appe ared to b e important in promoting scccllin,n:
emergence. Fie l d covering devices were evaluated and a bar harrow vras dev e lo ped and adop te d as a standar d c overing proc e du re . The importance of covering the seed appeared to be more pronounced wit h lar ge seeds such as
maize and b ar l ey than with smal l er s eeds such as luc erne . A s trong re la ti onsld p b etwe en vi sual scori:�of the amount and type of cover, and seed ling emc�gence
data was e s tab lished. This f avoured c overing media wi th a predomi nance of unbr oken dead pas tur e mu lch, compar ed wi th loos e soi l and rubble.
The performanc es of a range of dri l l c oulters o perating �t s low speeds in as so ciati on wit h the bar har row, were c om pared in t erms of p lant responses under s o i l m o i s ture stress . An experimenta l chis e l cou lter l'las deve lo ped t o obvi a t e the no t ed shortc omings of some o f these exi sting coult ers. In
contras t to the "V" shaped gro oves lef t by most cnulters, the chisel c onfined most of i t s s o i l di s turbance to sub surface layers, wi th a narrow opening at the
surface .
With a ll coulte rs, seed germina tion ap1eared t o b e les s aff ected by c oulte r d e si gn t han s eedling emer genc e because of sub surface mortali ty of seed l ings. In this re spe ct c lear s ee d ling eme rgenc e res ponses favoured the
2
•.
chi s e l c o ult er. Maximum wheat seedling emergence wi th the chi s e l coulter as sembly was 77%, whi c h was s ignificantly greater than ho e and tri p le disc coulter s wi th 27% and
26%
re spective ly . As the ini tial soi l mois t ur e leve l was rais ed in o ther e:�eriments the magnitude of the se differenc e s decreased but the o rder of ranking remained. A22%
comparative de crease in ini tia lsoi l moisture c ontent was necessary t o reduce the p erf ormance of the c hi se l coulte r t o a simi lar level t o thc.t o f the h o e and triple di sc c ou l t e r s .
D iffi culty was experienced i n accura te ly moni tor ing in-groove s o i l moistur e re gime s, bu t i rrigat i on response s and gravime t ric determinations of sub sam p le s sugge s t e d that t he ab i li ty of gro oves to retain avai la b le soi l moisture was a c r i ti cal factor in the p lant emergence response s .
Soi l temperature s· appeare d not to b e grea t ly affected by c oulter type i n the s e experiments a lthough the in-groove minimum temperature with the chi se l cou l t er was si gnif icant ly higher than the hoe and trip le di s c c ou lters in one experiment.
Observation of the m odes of ac t i on of coulters showed that the chi sel and hoe coulters produ c ed some upward soi l heaving whi le the tri ple disc appeared to operate with a downward and outward wedging ac tion in the soi l . A n incre as e in soi l densi ty under the gro ove re su lted from pass age of the
trip le disc coulter b ut no eff ect on dens i ty was seen wi th the chise l or hoe cou l t ers . The down f orces r e quired for
38
mm pene tration of all cou lters tes ted,. appear ed also t o be c lo s e ly related to their mo des of act ion and re lative ly insensitive to s o i l mois ture conte nJ.; in the stres s ranee. In this re spe ct the tri p l e disc required 1 . 4 times more force than the dished disc coulter and from2.3
t o 4.6 t imes more force than a ranee of 4 other coulters .Fie ld t e s ts o f the wear rates of chi s e l c oult ers cons tructed of various s t e e l based materia ls, wi t h and without hardening treatments, suggested a number of pre ferred t rea tments but c ou ld no t es tab lish any differenc e in wear rat e f rom coul ters o perating in the tract or whe el marks compared with
those operating in unmarked s o i l.
Section
1 2 3
TABLE OF CONTENTS
DEFINITIONS
GENERAL INTRODUCTION
Page
1 2
DEVELOPMENT OF EXPERIMENTAL APPARATUS AND TECHNIQUES
3 . 1 INTRODUCTION AND REVIET!l
'3. 1 . 1 Seed germination requirements
3 . 1 . 2 Seedling emergence under direct drilled conditions
3. 1 . 3 Failure of techniques and machines
5 5 5
5 6
3 . 1 . 4 Reasons for direct drilling failure 6
3. 1 . 5 Groove formation and covering 7
3. 1 . 6 Desirable drill and coulter features 1 1
3. 1.7. Experiments comparing drill performance 13 3. 1 . 8 Identification of important soil physical
parameters 1 5
3. 1 . 9 Monitoring in-groove conditions 16
3. 1 . 10 The physical effects of coulters travelling
through soil. 16
3. 2 OVERCOMING THE DISADVANTAGES OF FIELD E.XPERIMENTS 17
3 . 2 . 1 Field equipment 18
3.3 DETAILS OF TECHNIQUES AND EQUIP��NT 19
3.3. 1 Turf block collection 19
Turf cutter 19
Protection 22
W�er �w� 22
Tillage bins 23
Soil disturbance 23
Lubrication 24
Vegetation 25
Soil cohesion 25
3.3. 2 Turf block extraction procedure 26
3.3.3 Turf block quality and site choice 35
3 . 3 . 4 Emptying of bins 36
3.3. 5 Preparation, storage and climate control of
turf blocks 37
Preparation Storage
Climate control
37 37 40
Section
DRILLING OF TURF BLOCKS AND T::TSTINGS OF DRILL COULTER PERFORHANCE
3 . 4 . 1 Description of support bed, moving gantry and tool 44
testing apparatus
Support bed 44
Drive chains 46
Motivation 46
Lubrication 48
Clutch 48
Overload 48
Gantry 49
Tool testing apparatus 49
3 . 4.2 Procedure 60
Bin matching 60
Drill coulter testing Covering and sealing
MEASURING TECHNIQUES RELATING TO PRE- AND POST-DRILLED TURF BLOCKS
3.5. 1 Physical measurements
Soil moisture content and matric potential Soil temperature within the groove
Type and amount of cover over the seed
Compaction in the bounding areas of the groove a. Beneath the seed
Penetrometer
Description of multipoint penetrometer Support bars
Hetering frame Support frame Procedure
b. Above the seed Soil-seed contact
61 63
63 64 64 68 68
69
69 69 70 70 72 72 74 75 75
Section Page
3. 5 . 2 Plant response measurements
(
seed fate counts)
7 5The proportion of seeds which failed t o germinate 7 5
The proportion of seeds which germinated but failed t o
emerge 7 5
The proportion of seedlings which emerged 7 5
The proportion of abnormal seeds or seedlings 7 5
3. 5 . 3 Field studies 76
Growth studies 76
3 . 6 DEVELOPMENT OF TRACTOR OR VEHICLE OPERATED FIELD EQUIPHENT 77
3 . 6 . 1 Bar harrow 77
Operating principles 80
3 . 6 . 2 Drill coulter field t est rig 82
3 . 6 . 3 Trailing arm, seed boot and chisel drill coulter assembly 84
Chisel drill coulter 84
Functional requirements 84
Trailing arm 97
Seed boot 97
3. 7 EXPERIHENTAL DESIGNS
3 . 7 . 1 Turf block studies Site and soil selection
Sampling procedure and subsequent h q ndling
3 . 7 . 2 Field studies
4 EXPERIHENTAL OBJECTIVES AND RESULTS
4. 1 OBJECTIVES
4.2 RESEARCH PRIORITIES
4.3 RESULTS
4 . 3 . 1 Experiment 1: The effectivensss of bar harrowing
(
field experiment)
99 99 100 100 101 102 102 103 105
105
Objective 105
Results 105
Discussion 106
4 . 3 . 2 Experiment 2: The effectiveness of bar harrowing with
differing seed sizes
(
field experiment)
108Objective 108
Results 109
Section
Discussion a. Lucerne b. Barley c. Haize
Summary of species response to harrowing
4.3.3 Experiment 3: The effectiveness of coulter design on seedling emergence (�ilot tillage bin
111 111 112 112 113
experiment) 114
Objectives Results Discussion
h.3.4 ExJleriment 4(a) The effect of coulter design on soil ph;ysical properties (pilot tillage bin
114 116 116
experiment) 118
Objectives
Results and discussion a. Cover
b. Seedling emergence
c. In-groove soil moisture content d. Seed dry matter
e. In-groove temperature
118 121 121 122 123 124 125 Experiment 4(b): The effects of coulter passage on soil 127
comnaction (pilot tillage bin experiment) Objective
Results Discussion
4.3.5 Exneriment 5: The effects of a range of drill coulters on selected plant and soil responses
127 127 128
(pilot tillage bin experiment) 131
Objectives 131
Results and discussion 132
a.
b.
c.
d.
e.
Cover
Seedling emergence In-groove soil moisture In-groove temperature Penetration forces
content
132 132 133 134 135
Section
Discussion of technioue
4.3.6 Exneriment 6: Comparison of the performance of selected drill coulters
(
main tillage binexperiment
)
Objectives
Results and discussion a. Cover
b. Seedling emereence and seed fate c. Relationship of cover and emergence
d. Soil moisture content and matric potential e. Soil temperature
f. Physical effect of drill coulters
selected 136
138 138 139 139 139 143 143 1/-l-4 147 4.3.7 Experiment 7: Comparison of the performance of 148
drill coulters
(
main tillage bin experiment)
Objectives
Results and discussion
a. Cover
b. Seedling emergence
c. Relationshin of cover and emergence d. Seed fate counts
e. Dry matter content of ungerminated seeds f. Herbage dry matter yield
g. Penetration forces
4.3.8 Experiment 8: The effects of soil moisture content on the performance of drill coulters
(
main148 149 1h9 149 151 152 154 155 156
tillage bin experiment) 157
Objectives 157
Results and discussion 157
a. Cover
b. Seedling emergence and seed fate c. Soil moisture content
d. Non-viable seed dry matter content e. Inter-relationshi�s
f. Herbage dry matter yields g. Penetration forces
4.3.9 Experiment 9: Comparison of the wear rate of chisel
157 158 160 162 162 162 167 coulters
(
field . experiment)
168Section Page
Objectives
168
Heasurements
169
Results and discussion
171
Effect of tractor 1-rheel marks
174
5 SUHHARY AND DISCUSSION
176
6
BIBLIOGRAPHY181
7
ACKNOHLEDGEMENTS186
8
APPENDICESList oi' tables
1. A comparison of ambient and beneath-rain-canopy temperature data during winter months
2. The effects on soil moisture of extracting and treating
41
turf blocks 43
3. The effects of bar harrowing on the seedling emergence of
direct drilled choumollier 105
4(a) The effects of cultivation, direct drilling and bar harrowing 109 on seedling emergence, dry matter ��eld and soil moisture
content of a lucerne crop
4(b) The effects of bar harrowing on seedling emergence of direct
drilled barley 110
4(c) The effects of cultivation, direct drilling and bar harrowing 5.
on the seedling emergence of maize
The effect of soil moisture content on the uptake by viable and non-viable maize seed
6(a) The effects of coulter type and bar harrowing on seedling
110 121
emergence of direct drilled maize 122
6(b) The effects of coulter type and bar harrowing on seedling
emergence of direct drilled maize (replicate 2 only) 123 7. The effects of coulter type on in-groove soil moisture content
following direct drilling and bar harrowing (replicate 2 only) 123 8. The effects of coulter type and bar harrowing on the dry
matter content of direct drilled non-viable maize seed 9. The effects of coulter type on in-groove temperature
following direct drilling and bar harrowing
10. Soil penetrometer resistance and drill coulter penetration force as affected by direct drilling coulter type
11. The effects of coulter type and bar harrowing on seedling emergence of direct drilled barley
12 The effects of coulter type on in-groove soil moisture content 124 125 127 132
following direct drilling and bar harrowing 133 13. The effects of coulter type on in-groove temperature
following direct drilling and bar harrowing
14. The effects of coulter type and bar harrowing on the seed fate of direct drilled wheat, with and without irrigation
135 141
15. The effects of coulter type on in-groove and undisturbed soil
temperature following direct drilling and bar harrowing 145 16. The effects of coulter type plus bar harrowing, and method of
sampling on seedling emergence counts of direct drilled wheat 151 17. The effects of coulter type and bar harrowing on the dry matter
content of ungerminated direct drilled wheat seeds 155 18. The effects of coulter type and bar harrowing on dry matter
production of direct drilled wheat seedlings
19. The effects of coulter type and bar harrowing on dry matter
156
yield of direct drilled wheat seedlings 164 20. Hardness treatments applied to direct drilling chisel coulters 168 21. The effects of hard surfacing treatments on the wear rates of
chisel coulters
22. The effects of position in relation to tractor wheel marks on the wear rate of chisel coulters
170 173
List of figures
1. The multipoint penetrometer (from Dixon, 56)
2(a) Side elevation of the Mk. 1 & Mk. 2 versions of the chisel coulter
71
94 2(b) Front & rear elevations, & plan view of Mk. 1 chisel coulter 95 2(c) Front & rear elevations, & plan view of Mk. 2 chisel coulter 96
2(d) �&. 2 chisel coulter assembly .and drag arm 98 3. The effects of direct drilling using chisel coulters followed
by bar harrowing, and hoe coulters with and without harrowing, on seedling emergence of barley
The principal characteristics of direct drilled grooves in a silt loam at moisture contents, 15%, 2o% & 27% (from Dixon, 56)
5. The effects of coulter type & bar harrowing on the seedling emergence of direct drilled wheat
115
130
140 6. The effects of coulter type on in-groove and undisturbed soil
moisture contents following direct drilling and bar harrowing 144
7.
The effects of coulter type on in-groove soil temperaturefollowing direct drilling and bar harrowing
8. The effects of coulter type & bar harrowing on the seedling emergence of direct drilled wheat
9. The effects of coulter type on the fate of wheat seeds following direct drilling and bar harrowing
10. The effects of coulter type on the fate of wheat seeds following 146 150 153
direct drilling and bar harrowing 159
11. The effects of coulter type on in-groove soil moisture content following direct drilling and bar harrowing 161 12. The effects of coulter type on the dry matter content of
ungerminated wheat seeds following direct drilling and bar
harrowing 163
List of plates
1. Exposed barley seed visible in the groove created by a hoe coulter in moist silt loam. (with acknowledgement to
L.W. Blackmore)
2. Dished disc coulters creating soil flaps in moist soil 3.
4.
The growth formation of a ryegrass shoot under a soil flap The turf cutter with a tillage bin attached
5 . Water discharge from the hollow turf cutter blade
6. Turf block extraction procedure;
7. Turf block extraction procedure;
8. Turf block extraction procedure;
bin
9. Turf block extraction procedure;
travel
10. Turf block extraction procedure;
(note the four lifting rings) 11. Turf block extraction procedure;
ends
12. Turf block extraction proc�dure;
tillage bin
(1) cutting lead-in channel (2) connection of tillage bin (3) elevation of rear of tillage (4) initiation of turf cutter ( 5) tillage bin at full depth (6) severing the turf block (7) uplifting turf block and
8 9 10 20 21 27 28 30 31 32 33
34 13. Removal of loose soil from the turf block ends with a wire brush 38 14. Placement of a prepared tillage bin into its tray, with the
rain canopy in the raised position
15. End view of the tillage bin support bed, showing; lower centre- 39
drive mechanism; top right- multipoint penetrometer 45 16. Gantry and tool testing apparatus, showing; centre - parallelogram
trailing arms attached to sub frame; upper centre- vacuum seeder, coulter support column & penetration weights; left- vacuum
accumulator; lower centre- hoe coulter & pre disc under test;
17.
18.
19.
20(a) 20 (b)
lo\'rer right- bar covering harrow section Placement of a tillage bin on the support bed The waxing of divots left by the scoop sampler
Groove "scratchers" attached to hoe coulter assemblies Bar harrow dimensions
Its operation in maize stubble after passage of dished disc coulters
50 62 66 79 79 81
21.
22 ( a ) 22 (b) 22 ( c )
23 . 24.
2 5 ( a ) 2 5 ( b ) 26 ( a ) 26(b) 26( c ) 26( d )
Drill coulter field test rig
Side view of chisel coulter assembly and drag arm Oblique frontal vie\v of the chisel coulter
Rear view of t he chisel coulter, shmving the diverging internal seed delivery tube , and the lateral wings The hoe coulter assembly a s tested
The triple disc coulter assembly a s tested
Typical direct drilled wheat seedlings (unirrigated) Typical direct drilled wheat seedlings (irrigated) T ypical direct drilled wheat seedlings (day 5) Typical direct drilled wheat seedlings (day 7) Typical direct drilled \vheat seedlings (day 9) Typical direct drilled \vheat seedlings (day 12)
27 Comparative wear rates of chisel coulter wings . The three separated \dngs are t he original unworn shape
83 87 88
89 107 119 143 143 165 165 166 166 173
1.
2.
3.
4.
5(a) (b) ( c ) (d) ( e ) ( f ) 6 ( a ) (b)
7
(a) (b) ( c ) ( d ) ( e ) ( f ) ( g) 8 ( a ) (b) ( c ) (d) ( e ) ( f ) 9 (a) (b) ( c ) (d) ( e ) ( f) 10 ( a )( b )
List o f Appendices
�ieteorological Data - Station E05465 - Mas sey University
Ambient and comparative temperature data , beneath rain canopies Comparative soil moisture contents of tillage bin turf blocks and parent soils in situ
Specifications of experiment
1.
Specifications of experiment
2
P�infall - Feilding trial area
1971/72
Direct drilled and conventionally so\vn lucerne , plant emergence count s . Direct drilled and cultivated lucerne plots, soil moisture status
Direct drilled barley, plant emergence count s
Direct drilled and conventionally sown maize , plant emergence counts Specifications of experiment 3
Direct drilled barley, plant emergence count s Specifications of experiments 4(a) and 4(b) Direct drilled maize , emergence count s
Direct drilling, in-groove soil moisture content Direct drilled maize seed dry matter percentage Direct drilling, in-groove temperature
Range analysis of in-groove temperature , direct drilling
Penetrometer resistance , direct drilled grooves and undisturbed turf Specifications of experiment 5
Pre-drilling soil moisture status of turf blocks Direct drilled barley, plant emergence counts
In-groove soil moisture content , direct drilling In-groove temperature , direct drilling
Range analysis of in-groove temperature , direct drilling Specifications of experiment 6
Seedling emergence
%,
direct drilled wheat Seed fate counts , direct drilled vTheatDirect drilling, in-groove and undisturbed matric potential Between direct drilled rows , soil moi sture data (day 36) In-groove and undisturbed soil temperature , direct drilling Specifications of experiment 7
Seedling emergence percentage , direct drilled wheat , whole plot count s
10
(c) Seed fate, direct drilled wheat, percentage of total seed pool (d) Dry matter percentage, direct drilled wheat seeds(e) Shoot dry-matter yields, direct drilled wheat, terminal figures
11
(a) Specifications of experiment 8 (b) Seed fate, direct drilled wheat(c) In-groove soil moisture content, direct drilling
(d) Non-viable wheat seed dry matter percentage, direct drilling (e) Drs weights of direct drilled wheat seedlings
12
(a) Specifications of experiment9
(b) Weight loss of chisel direct drilling coulters (c) Weight loss of chisel direct drilling coulters
13
DefinitionsDEFINITIONS
1. Unless defined in Appendix 13 or otherwise explained in the text, all references to agricultural machines or components thereof have the meaning stated in British Standard 2648:
1963, "Glossary of Terms Relating to Agricultural Machinery and Implements".
1.
