Strategic nitrogen fertiliser use on perennial ryegrass and white clover pasture in north-western Tasmania

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.

2017 ◽  
Vol 155 (9) ◽  
pp. 1381-1393 ◽  
Author(s):  
J. McDONAGH ◽  
T. J. GILLILAND ◽  
M. McEVOY ◽  
L. DELABY ◽  
M. O'DONOVAN

SUMMARYPerennial ryegrass and white clover (WC) have been shown to form compatible mixtures for pasture production under temperate climates. The inclusion of WC has the potential to enhance the performance of grass swards, but the extent of the improvement under contrasting grazing management strategies is unclear. Grazing rotation and fertilizer nitrogen (N) use have been identified as two major factors that can influence the performance of grass–clover swards. The objective of the current study was to examine the effect of differing grazing rotation lengths and the level of N application on the dry matter (DM) yield performance of grass–clover and grass-only swards as well as on WC productivity and persistency under animal grazing. Swards were managed by N application and grazing rotation length: High-N swards were managed on a 21-day grazing rotation (Man 1) and low-N swards were managed on a 30-day grazing rotation (Man 2). The four treatments were: 250 kg N/ha without WC (HN−C), 250 kg N/ha with WC (HN+C), 100 kg N/ha N without WC (LN−C) and 100 kg N/ha with WC (LN+C). There was a significant management × WC interaction over the 3 years for annual DM yield. The LN−C swards produced lower DM yield (−1917 kg DM/ha) than the swards of the other three treatments (11 167 kg DM/ha). Management had a significant effect on annual DM yield with Man 1 swards yielding 801 kg DM/ha more than Man 2 swards (10 288 kg DM/ha). The inclusion of WC yielded significantly more annual DM yield (+1009 kg DM/ha) than grass-only swards. Notably, LN+C produced the same annual total DM yield as swards under High N and a 21-day grazing rotation. Total WC DM yield and proportion across the year was altered significantly by management. Higher N fertilized swards at shorter grazing intervals had a lower WC DM yield (−1544 kg DM/ha) and proportion (−0·13). Dry matter yield of WC with low N application can be similar to that at high N levels if rotation length is used as a mechanism to determine grazing timing. Variations in WC productivity into the final year of the experiment indicate that persistence of significant contributions to DM yield by WC under low N at longer grazing intervals remains unclear after 3 years.


1997 ◽  
Vol 37 (2) ◽  
pp. 165 ◽  
Author(s):  
J. S. Dunbabin ◽  
I. H. Hume ◽  
M. E. Ireson

Summary. Perennial ryegrass–white clover swards were irrigated for 3 years every 50, 80 and 120 mm of crop evapotranspiration minus rainfall (ETc–R) and water ponded on the soil surface for either 4, 12 or 24 h at each irrigation. Pasture production and clover content were highly seasonal, peaking in spring and autumn. Frequent irrigation increased dry matter production by an average of 56%. When irrigating at 50 mm ETc–R, dry matter production was decreased by ponding water on plots, 17% for 12 h ponding and 14% if ponded for 24 h. However, when irrigating at an interval of 80 mm ETc–R ponding increased dry matter production by 7% for 12 h ponding and by 25% for 24 h ponding. Ponding also increased production at an irrigation interval of 120 mm ETc–R by 25% for 12 h ponding but only by 2.4% for 24 h ponding. While these increases in dry matter production are large in relative terms the absolute increase in production is small. More water infiltrated per irrigation at longer irrigation intervals, and at longer ponding times. Frequently irrigated, rapidly drained swards used irrigation water most efficiently. The small gain in dry matter production achieved by prolonging ponding at longer irrigation intervals is an inefficient use of water and likely to recharge regional groundwater systems. Oxygen diffusion rate measurements suggested that ponding for as short as 4 h was likely to cause waterlogging stresses and that these stresses were higher when irrigating frequently. The relative increase in waterlogging stress by extending the period of ponding from 4 to 24 h was small.


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.


1976 ◽  
Vol 86 (2) ◽  
pp. 335-342 ◽  
Author(s):  
R. Marsh ◽  
F. J. Gordon ◽  
J. C. Murdoch ◽  
W. E. G. Stevenson

SummaryThe effect of season of harvest and previous seasonal applications of fertilizer N on the response of perennial ryegrass/white clover swards to pre-cut applications of fertilizer N was studied in three consecutive years on different sites. Herbage D.M. yield responded in a curvilinear manner to increased pre-cut N application rates. There was a tendency in all experiments for the marginal response of herbage D.M. to increased pre-cut N application rates to decrease as previous seasonal fertilizer N application rates increased. Although the effect of season of harvest on the response of herbage D.M. to pre-cut N application rates varied with site/years, it was concluded that the marginal response of herbage D.M. to pre-cut N application rate varies little throughout the greater part of the growing season. The exceptions to this are the very early and late harvests and swards that receive low supplies of N from the sward/soil complex. The results are discussed in relation to other published data and to their possible use in the control of the seasonal pattern and total seasonal supply of herbage D.M. for rotational grazing management systems.


Author(s):  
J.P.J. Eerens ◽  
D.L. Ryan

White clover is often listed as one of the factors contributing to profitable pastoral farming in New Zealand. The positive aspects of white clover have been presented in a balanced manner in publications by scientists, environmentalists and farmers able to exploit these positive aspects. Increasingly, pastures contain sub-optimal levels of clover, as a result of pasture management that is detrimental to clover, including the increasing use of fertiliser nitrogen. In some regions of New Zealand, farmers can legitimately point to pests such as the clover root weevil and factors such as the ryegrass endophyte as causing restrictions in clover production, but this is less the case in Southland. Environmental conditions in Southland are well suited for ryegrass-white clover pastures. Wellmanaged ryegrass-white clover pastures containing the best regional cultivars can achieve high financial returns. A number of trials at the Gore Research Station are reviewed; they demonstrated that on mixed ryegrass-white clover swards farmers can produce nearly 25% more dry matter, 40% more carcass weight and 25% more wool than on pastures with ryegrass alone receiving 270 kg N/ha/year. The yield advantage would have been greater still if they were compared with typical Southland pastures. Not only was 180 kg more carcass and 17 kg more wool produced per hectare on mixed swards, but nitrogen fixation by clover produced more than $300 worth of nitrogen per hectare. The yield advantage achievable from the ryegrass-white clover swards requires specific pasture management, particularly in spring- summer and the use of adapted white clover cultivars. Keywords: cultivars, Lolium perenne, nitrogen, pasture production, perennial ryegrass, set stocking, Trifolium repens, white clover, wool


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.


1997 ◽  
Vol 45 (2) ◽  
pp. 263-275
Author(s):  
R.L.M. Schils

In a field trial in 1989-93 on clay soil at Lelystad, Netherlands, a mixed sward of Lolium perenne cv. Profit and Magella and Trifolium repens cv. Retor was given annual applications of 0, 25, 50, 75 or 100 kg N ha-1 and was cut 4-5 or 6-7 times a year. In a trial in 1992-94 on sandy soil in Overijssel, a sward of L. perenne cv. Meltra, Citadel and Condesa oversown with T. repens cv. Retor in 1991 was given annual applications of 0, 50 or 100 kg N ha-1. Average annual dry matter (DM) yields were 14.66 and 13.76 t ha-1 year-1 for the clay and sandy soil, respectively. Yields increased with increasing N rate at both sites. Cutting frequency had no consistent effect on DM yield, and there was no significant interaction between N rate and cutting frequency. T. repens contents decreased with increasing N rate, reducing the DM yield in the cuts after the first in the fertilized treatments. Annual N yields were not affected by N application. The higher cutting frequency increased the T. repens content from 36 to 47% and the N yield from 458 to 524 kg ha-1, but did not affect the DM yield.


1998 ◽  
Vol 49 (7) ◽  
pp. 1141 ◽  
Author(s):  
M-G. Batson

Renovation of pastures dominated by bent grass (Agrostis castellana), by killing the vegetation with herbicides followed by cultivation and re-sowing, according to current recommendations, can kill up to 95% of the bent grass. To improve the success of killing bent grass and reducing the likelihood of regeneration from rhizomes after renovation, the behaviour of rhizomes after fragmentation was studied in pots. Rhizomes were cut into different lengths (15, 40, and 100 mm) to contain 1, 3, and 8 nodes per section and planted at depths of 25, 50, 75, 100, and 200 mm in cultivated soil, with or without competition from establishing seedlings of perennial ryegrass and white clover. The proportion of bent grass shoots developing from buried rhizomes was reduced to <10% when rhizomes were broken into sections containing only a single node and buried at or below 75 mm. Even after 3 months burial, an average of 0, 0·2, and 0·4 nodes in 1-node, 3-node, and 8-node sections, respectively, were still viable after fragmentation and could potentially develop, should conditions change, ensuring regeneration. The presence of newly sown pasture did not affect either the development of nodes or the vigour of shoots of bent grass during the 3-month measurement period. Pasture production, however, was reduced with increasing bent grass shoot production such that 8-node sections buried at 25 and 50 mm produced up to 3 times more dry matter per pot than other pasture components, giving bent grass a competitive advantage.


1978 ◽  
Vol 29 (1) ◽  
pp. 9 ◽  
Author(s):  
SJ Cook ◽  
A Lazenby ◽  
GJ Blair

The cessation of superphosphate dressings to a perennial ryegrass-white clover pasture which had received more than 1300 kg superphosphate per hectare resulted in pasture degeneration. Within 2½ years of the last superphosphate dressing, the sown species comprised less than 15% of the harvested forage, compared with 53% in the forage from plots receiving 500 kg superphosphate per hectare per year. Only where superphosphate was applied at either 250 or 500 kg per hectare per year did the ryegrass persist. As perennial ryegrass was the only species to contribute to pasture production in winter, this botanical degeneration significantly reduced winter production. The phosphate-deficient pastures were invaded by summer-growing native grasses such as red grass, which, although contributing substantially to summer production, made little or no growth in the 6 months April to September inclusive.


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.


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