The effect of defoliation interval in winter on pasture productivity in winter and spring: a regional comparison

1990 ◽  
Vol 30 (3) ◽  
pp. 357 ◽  
Author(s):  
JM Belton

Forty-five plots (3 by 2 m) of perennial ryegrass-white clover pasture were randomly allocated within 3 sites to 5 winter defoliation interval treatments to determine the effect of site on best defoliation interval as measured by winter and spring herbage accumulation. Defoliation intervals were 14, 28, 42, 56, and 84 days. The defoliation intervals resulting in maximum total winter dry matter (DM) accumulation at sites 1 and 3 were 42, 56 and 84 days. Available feed accumulated at the end of winter was highest for the 84-day defoliation interval at both sites (2.0 and 1.4 t DM/ha, respectively). At site 2, maximum total winter DM accumulation was achieved for defoliation intervals of 28, 42 and 56 days. Available feed accumulation at the end of winter was 1.2 t DM/ha for the 42-day interval and did not increase thereafter. The difference in response was associated with pasture composition. The results of the experiment showed that there is scope for flexibility in winter grazing management to suit livestock requirements without compromising total winter dry matter accumulation.

2015 ◽  
Vol 77 ◽  
pp. 89-94 ◽  
Author(s):  
L.M. Cranston ◽  
P.R. Kenyon ◽  
S.T. Morris ◽  
P.D. Kemp

Many farmers are sowing mixed swards containing chicory (Cichorium intybus), plantain (Plantago lanceolata), red clover (Trifolium pratense) and white clover (T. repens) (hereafter termed herb and clover mix). This herb and clover mix has comparable annual dry matter (DM) production to perennial ryegrass white clover pasture (rye/wc), however, it has a different pattern of growth, producing more DM during summer and autumn. The herb and clover mix also has a higher nutritive value and is able to support greater rates of animal production, especially over summer, than rye/ wc in both sheep and cattle. The herb and clover mix is most suited to a rotational grazing interval of 3-4 weeks to an 8 cm residual height, with no winter grazing. When managed appropriately the herb and clover mix is able to persist for at least 2 years and up to 5 years under both sheep and cattle grazing. Keywords: Cichorium intybus, Plantago lanceolata, Trifolium pratense, Trifolium repens, legume, perennial, nutritive value.


Author(s):  
C.J. Korte

The patterns of herbage accumulation and the tiller dynamics of a "Grasslands Nui" perennial ryegrass dominant pasture were compared under two grazing intensity treatments in late spring. Rank stemmy herbage developed with lax grazing whereas dense leafy pasture developed with close grazing. Dead herbage and uneaten stems in rank pastures shaded photosynthetic tissue. Leafy swards had a higher herbage accumulation rate and a higher tiller density than stemmy swards. Methods of achieving leafy pasture on farms by combinations of hard grazing, forage conservation and mechanical topping are discussed briefly.


Author(s):  
A.J. Harris ◽  
K.R. Brown

THE NEED for greater efficiency in pasture utilization is becoming more marked as stock numbers rise. In Southland, much of the increase is arising from higher stock concentrations and rates of almost 10 sheep per acre are known (Lawlor, 1970), although the average is considerably lower.


Author(s):  
S.C. Moloney ◽  
R.J.M. Hay ◽  
J.A. Lancashire

The performance of Kopu white clover was compared with that ot Huia and Pitau under intensive dairy grazing management at Taupo and the Manawatu. Sampling included both dry matter production and detailed white clover stolon and leaf measurements. These trials have shown that there are significant advantages to be gained from the use of Kopu over both Huia and Pitau. in rotationally grazed cattle swards, particularly during autumn and winter. At the Taupe site where Kopu was sown with high endophyte perennial ryegrass, seasonal white clover yields from Kopu were 120% greater than from Huia in autumn and 160% in winter. At the Manawatu site with Matua prairie grass as the grass component, the advantage of Kopu over Pitau was 105% in autumn, increasing lo 150% by winter. These results are discussed in relation to the significance of Kopu to dairy farming in the central and southern North Wand region. Keywords: rotationally grazed swards. cool season activity, erect habit, dairy pasture, intensive dairying


1997 ◽  
Vol 48 (6) ◽  
pp. 811 ◽  
Author(s):  
A. R. Lawson ◽  
P. W. G. Sale ◽  
K. B. Kelly

A field experiment was carried out to investigate whether changes in winter and post-winter defoliation frequency would increase the white clover content of an irrigated perennial ryegrass–white clover pasture in northern Victoria. Pastures defoliated every 4 weeks during winter had higher white clover growing point (stolon apices with at least 2 nodes) density at the end of winter than pastures defoliated every 8 weeks or those receiving a single defoliation after 16 weeks, but these differences did not affect the clover content in the spring. Reasons for this are suggested. Pastures defoliated at 8-week intervals in winter were the most productive over winter{early spring. Less frequent defoliation (4 v. 2 weeks) during the post-winter, September–May period reduced white clover growing point and perennial ryegrass tiller densities. However, the white clover growth rate during this period was increased by less frequent defoliation, whereas the ryegrass growth rate was reduced, resulting in an increase of 10% in the white clover content, and a 1·9 t dry matter (DM)/ha increase in total DM produced. This higher clover content and pasture yield during spring–autumn with less frequent defoliation has important implications for the management of irrigated perennial pastures for the dairy industry in northern Victoria.


Author(s):  
C.J. Korte ◽  
G.W. Sheath

Dry matter accumulation patterns in pastures are the net result of two processes: the growth of new herbage and the death, and disappearance of old herbage. The relative importance of these two processes in influencing regrowth is discussed and illustrated with data from two markedly different pasture types. In a Nui ryegrass/ white clover pasture and a pure Maku lotus sward, defoliation intensity and season markedly influence the accumulation of dead material, its subsequent disappearance, and hence net dry matter production. The effect of new growth on dry matter accumulation was greatly diminished by within-canopy dry matter losses. The implications of herbage death and disappearance are discussed with reference to the adequacy of certain experimental techniques in estimating herbage dry matter production.


1998 ◽  
Vol 38 (2) ◽  
pp. 155 ◽  
Author(s):  
R. J. Eckard ◽  
D. R. Franks

Summary. The strategic application of nitrogen (N) fertiliser on temperate pasture is a popular management tool for boosting pasture production, particularly when low soil temperatures limit clover-derived N availability. The responsiveness of a perennial ryegrass and white clover pasture to increasing rates of N fertiliser (0, 15, 30, 45 and 60 kg N/ha), applied as a single application, was investigated for 5 pre and 5 post mid winter N application dates. The trial was laid out in a randomised split-plot design, replicated 4 times, with N application date in the whole plots and N fertiliser rate in subplots. Herbage yields were estimated by mowing small plots, with animals excluded for the duration of a single regrowth period on each plot. The data are presented as averages for the 5 pre and 5 post mid winter responses separately, as the means of the pre and post winter partitions were significantly (P<0.001) different at all rates of N fertiliser for both years. Significant (P<0.05) yield responses were noted between increments of N fertiliser up to the 45 kg N/ha application rate. In contrast, no significant (P>0.05) increases in dry matter yield were noted between the 45 and 60 kg N/ha rates in all but one response, consistent with diminishing returns. The efficiency with which N fertiliser was utilised ranged between 9.0 and 15.9 kg N dry matter/kg. Nitrogen efficiency was consistently lower at the 60 kg N/ha rate than for lower rates of N fertiliser. The application of N fertiliser increased pasture dry matter yields by between 582 and 703 kg dry matter/ha. Based on the 1997 cost of urea, the additional forage produced cost between 6.4 and 10.1 cents/kg dry matter. The data are reviewed in terms of the potential for strategic N fertiliser applications during the winter, while still maximising utilisation of clover-derived N during the warmer months.


Author(s):  
A. Hernandez-Garay ◽  
J. Hodgson ◽  
C. Matthew

The objective of this trial was to study the effect of variation in the timing and duration of lax spring grazing on tiller dynamics in perennial ryegrass. Tiller population density, tiller appearance, and tiller death were measured in a sward of perennial ryegrass (cv. Grasslands Nui) and white clover (cv. Grasslands Tahora) grazed by sheep every 14 days to 4 cm (hard) and every 21 days to 7 cm (lax) residues. The experiment comprised 2 lax spring grazing treatments [lax grazing October 26December 8 (H-H-L-H) and September 16 December 8 (H-L-L-H)], plus a hard grazed control (H-H-H-H). Ryegrass tiller density was greater in H-L-L-H than H-H-L-H and H-H-H-H from mid summer until the end of the trial in autumn, mainly because of the difference in tillering activity late in December. Tiller appearance rate increased in all the treatments from September to the end of January, and was particularly high late in December in the second regrowth after grazing of the apices of the main group of reproductive tillers. The lax grazing management strategy increased tiller appearance rate during late December and January. Higher tiller losses in lax grazing treatments over the same period were not offset enough to affect this advantage. The response in tiller population density was greater following the extended period of lax spring grazing. Keywords: grazing management,Lolium perenne, reproductive growth, tiller population density, tiller demography, Trifolium repens


Author(s):  
S.L. Woodward ◽  
K.A. Macdonald ◽  
W.A. Carter ◽  
J.P.J. Eerens ◽  
J.R. Crush

1999/2000 and 2000/2001 were the first two complete seasons of a replicated farm systems trial designed to measure the effects on whole farm profitability (Economic Farm Surplus (EFS) of mixtures of ryegrasses and white clovers released on to the market recently, or at least 15 years ago, and rotationally grazed by dairy cows. All the pastures were sown in late autumn 1998. There were four treatments with all combinations of 1980s (80R), and late 1990s (98R) ryegrasses, and 1960s (60C)and late 1990s (98C) white clovers, each replicated 3.0 times in a randomised block design giving twelve 4-ha, self-contained farmlets stocked with three Friesian cows/ha. Milksolids production was unaffected by either ryegrass or clover cultivar age, but there was a significant ryegrass x clover cultivar interaction reflected as higher milksolids production on the 80R/98C treatment than the 98R/98C treatment in 1999/2000. This was a result of a higher clover content in the 80R/98C pastures compared with other treatments. Although the difference in clover content was still present in 2000/2001, the wetter summerÂ-autumn meant the ryegrass maintained a higher nutritive value than in the previous season under dry conditions, so clover content did not affect milksolids production in 2000/2001. There were no main treatment effects on EFS in either season, but there was a significant ryegrass x clover interaction in 1999/2000 shown as a higher EFS on the 80R/98C treatment than on the 98R/98C treatment. Keywords: cultivars, dairying, Economic Farm Surplus, milksolids, perennial ryegrass, white clover


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