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MASSEY CCtLEGE LIBRARY PALMERSTON NORTH, N.Z.
I I I
IE
IV
'l'he Recoznition of the Treading Effect
The Influence of the llninv:11 on the Tre[uling Effect :i.1he Effects of Shee]? Treading on Plant and. Soil Sheep Treadin1 Studies 2.n0. Pasture Yie lei
The DeveloT:r:1e11t of the .trrti Ti ci .:3 l I·loof I'he Ex1)erirr.ent
ii Descrii)tion of the 1\rea usec1, I...a.yout ancl Bsta.blisi1- ff!.ent of Plots, !~nr: +br:. tion of Treatments Sar!1T:,linz I::ctt1oc1s Etncl E:-.:-~y.3ri1nenta .. l Techniqctes
P;.c.LT I llESUUrs .:.;. The artificia.l tree_c1ing tx·eat1r1ent
• Statistical Techniq1...es
C. The cl ry ~~ ... eight yiela~ o±"'> each s~:ecies
~. Tiller counts
I~. The d r2r -,.,rei2~ht yield. o:f o,;ne:. s1:::ecies
·?. 'l1he
cr~r ..
-tre ~1t yield of Poa. sr:~.G-. Growir!:2: :,:oint measm'C!:1ents fI. Soil rnoistu1"e data_
I. Bulk density measurements at three depths
PJ!.';>T II I:ISCUSSIO?l
PJ{llT I IYIT}iODlJCTIO?,T FiJtT IX lIBSULTS
J.\. 'fhe artificia_l treac1in,; treatn!ent
c.
~rhe ClrJr v.riight 2ri,3lcl of ea.ch s~r:0cies Tiller countsD. C'rrov;in3:
r~
int rneasurernents E. Soil 1:Loisture di:.i.to"¥li'1• Bulk a_ensi ty rneasurernents at foul'"' deT:>ths
:g ib liogra1)hy Acknov;lec1gments
1h:c1Je nd ices
P.A::;T III DISOJSS::1::0lT
4
7 13 34
57 38 4.-1
50
51
55 57 61 63
66 76 77 78 7g 2\0
83 87 87 90 96
LIST OF FIGUiIBS
:t. The Artificial Hoof
2. Plan of the Experir'.1ental Area Ie.yout for the lmtwnn Trial
3. Dry ·![eight Production Curves. J\.utunm Tri:::i.l 4. Tiller Counts. _tiutumn '.11rial
;J. Layout for the Sr,ring Tria1 6~ Dry Ileir~ht ProclUction Cur·ves
Sprin1~ Trial
? , Tiller Counts. Sr)rinr£ Trial
8a. 1 J,bno:rmal I tille:cs. Perennial I-:.yeg:rass Sb. 1 Abnornw.11 tillers. Cocksfoot
~)a. 1 iibnormal I t ille:r·s. Bro-,mtor 9b. 1l,bnormal1 tillers. 'l'imothy
10. Position of G}~O'::inz 1-'oints. S:prin[; 'l'rial
Facing Paae
54.-
77 80
e2a
r32b E32b Facin0· Fc:.ge
87
Table
LIST OF T.l\.BIES AU TUlvJN TRIAL 1. :Mean a.ry weight yiela.. Perennial ryegrass 2., Mean dry Yi'eight yield. Timothy
5. 1:ean dry ,wight yield. Cocksfoot 4-. l1ean dry weight yield. Broi.mtop
5. Analyses of variance of the combined yield of al1 species at each sarrr_pling date
6. Results from testing for changes in mean dry weight yield with approximate "t11 test
7. lfoan tiller numbers. Perennial ryegrass 8. lJean tiller numbers. Timothy
9. !,:ean tiller numbers. Cocksfoot
10. Results from testing for changes in mean tiller munber with approximate "t" test
11. 1foan dry weight yield of other species in Perennial ryegrass 12. JYiean dry weight yield of other species in Timothy plots 13. Eean dry vreight yield of other species in Cocks:foot plots 14. Mean dry weight yield of other SJ)ecies in Brovrntop plots :U5. Mean dry weight yield of Sagina ·orocumbens L.
16, Mean dry weight yield of Trifolium dubium Sibth 17. Mean ary weight yield of' Trifoli1..m1 repens L.
18. Mean cry weight yield of Rumex acetosella agg.
19.
]\:ean dry ,veight yield of Crepis canillaris(L)
Wallr.20. 1\Cean dry weight yield of Poa S-i:m.
21. Transformed data and true mean :9ercentages of growing rJJints above the soil surface
22. Relative mean occurrence of growing points above the soil surface
23.
24.
25.
26.
27.
rfoan bulk density measurements. Perennial ryegrass Mean bulk density measw:ements. Timothy plots r,Iean bulk density measurements. Cocksfoot plots Mean bulk density measurements. Browntop plots Bulk density measurements. Coefficient of variation
plots
(o")
;o28. Comparison of' observations on the treading resistance of certain other species
plots 52 52 52 52 53 55 56 56 56 57 58 58 58 58 60 60 60 60 60 61 62 63 64 64 64 64 65 71
LIST OF TABIES ( Cont. ) Table
29. Comparison of bulk density values
30. Comparison of mechanical analyses of :sbll types_
SPRIN:3- TRIAL 31. 1foan dry weight yield. Perennial ryegrass 32. lfoan
cry
weight yield. Timothy33. 1.:eancry weight yield. Cocksfoot 34. Mean dry ·1reigl1t yield. Brovrntop
35. 1.'.:ean ti1ler nu:;1bers. Perennial ryegrass 36. Hean tiller numbers. Timothy
37. l1ean tiller numbers. Cocksfoot
38. Results fro:-'1 testing for changes in mean tiller nwnber with a!)~·roximate "t" test
3:). l::ean :i;:ercentage occurrence of I abnor:nal' tillers in T :plots LLn
-
,_..
Mean • , 1 , . •poSlv10D of' the gro;·fing JX) int. Perennial ryegrass
LL1
~--
Eean :position of the growing :901.n..,. • .L. Timothy 1foan position o:t' the growing })OLD;,. • .L. Cocksfoot 43. Hean position of the grovring point Browntop'.'14.
Relative mean occUcTence of growing points above the soilsuxface prior to treading
45. 1.:ean percentage of tillers showing internode elongation.
Perennial ryegrass
4-6$ lfean percentage of tillers shovring internocle elongation.
Timthy
73 74
78 79 79 79 81 81 81 82 83 84 84 84 84 85 86
86 47. L:ean r:ercentage of tillers showing internode elongation. Cocksfoot 86 48. J;:ean percentage of tillers shm7ing internode elon6ation.Brownto:r,, 86 49. 1:ean bulk
50. l{ean bulk 51. 1:ean bulk 52. l2ean bulk
densities.
densities.
densities.
densities.
Perennial Timothy Cocksfoot Brovmtop
ryegrass 88
88 88 88
CH.APTER I INTROLUCTION
The depenclence of New Zealand's economy up,n grassland has f'requently been emphasiz3d.
The main features of the pastoral farming systems are; high prod- uction pastures, grass/clover combinations, mineral fertilisers, and all- the-year outdoor grazing at relatively high stocking rates (Sears, 1959)
.
Corkill (1957) has dem:mstrated the role of pasture plant breeding and seed certification. Sears (1953) has shmvn the importance of pasture top- o.ressing, the grazing animal, and white clover in the improve:n:-::nt of' soil fertility. However, many other methods of increasing the production and
1 .:. . h b " .
t. ' .
1 v.._uti isac.1.on of er age are uncter roves 1.ga1;1.on 1,..i!.vans, 1000).
In general, grazing techniques have been based on a rotational system for it was believed th..at this method had imp::>rtant advantages over continuous grazing systems (Lev-y, 1950). Hovrever, the work of JfoMeekan (:.960) and Freer (1960) with dairy cows, and I.ambourne (1956) with sheep, shovred that v;iu.e differences in grazing technique have comparatively little effect on yield/acre of pasture and stock. The production efficiency vro.s mainly dependent on a high stocking rate.
There is little information to indicate the u1)per limits of the
-1.:!._ I d
stocking rate. At Rualcura, stocking levels of .q: cows/acre have not reduce pasture production (Campbell, 1961)~ ard Freer•s studies on irrigated grass- land in Victoria, have not produced evidence of sward deterioration a:fter two years of grazing at 2 cows/acre. · However, Edmotrl (1958a) and 1,1itchell ( 1960) have suggested that treading may place a ceiling on total herbage productivity.
In a review of literature, ) observed that al
the occurrence, of' the effects of
'
beenthe overall those of
to as
,
increasedso Further id-
in their reaction to
In s J. •.1.. l, 7
rate
i+ _..,
3 The grovrth curvre of the species, as affected by treatments in the .Autumn anci Spring of 1961, ·were :follov;ed. l.leasurements o:f some of the
comr_,anents of this gro1;Ttb. data were taken, and an attenr_pt to define the :position of the growing point in relation to ground level vras made.
Finally, changes in soil density due to the treading treatment were 1::1eas1c.lred.