Effects of initial sowing rate and subsequent grazing management on the growth and clover content of irrigated white clover - perennial ryegrass swards in northern Victoria

2005 ◽  
Vol 45 (12) ◽  
pp. 1595 ◽  
Author(s):  
K. B. Kelly ◽  
C. R. Stockdale ◽  
W. K. Mason

Two experiments were conducted over 3 years. One was of factorial design involving 2 sowing rates of white clover (Trifolium repens L. cv. Haifa; sown at 8 or 3 kg/ha) and perennial ryegrass (Lolium perenne L. cv. Grasslands Nui; sown at 5 or 15 kg/ha) grazed by dairy cows at 2 frequencies [frequent (2–3 weeks in spring/autumn) and infrequent (4–6 weeks in spring/autumn)] and 2 intensities [hard (residual rising plate meter heights of less than 4 cm) and lax (residual rising plate meter heights of more than 5 cm)]; and the second was a regression design involving 5 sowing rates of white clover and ryegrass ranging from pure clover to pure ryegrass (sown at 10/0 through to 0/20 kg/ha), all grazed frequently and at a hard intensity. The hypotheses tested were that (1) pure white clover swards would be at least as productive as those that contained ryegrass, and (2) more frequent grazing would result in greater quantities of DM removed, while hard grazing would maintain a higher clover content. In general, the hypotheses were confirmed. Over the 3 years of the experiments, pure white clover swards were at least as productive as mixed swards in a situation where no nitrogen fertiliser was applied. In the first year, the amount of DM removed declined (P<0.05) as the ryegrass sowing rate increased, but by year 3, the pure clover treatment out-yielded the other treatments. Except for the first year, frequent grazing resulted in more (P<0.05) DM removed than did infrequent grazing. Frequently grazed swards also had higher daily net photosynthesis after grazing than did the swards in infrequently grazed treatments, and achieved maximum levels of photosynthesis more quickly. There was no difference in photosynthesis rate, despite significant differences in clover content, between sowing rate treatments, regardless of grazing management. Initial sowing rate had a large effect on clover content in year 1, but by year 3, most of this had disappeared as clover contents rapidly converged. Frequency of grazing had its greatest effect on clover content in year 1, with infrequent grazing resulting (P<0.05) in the greatest clover contents. Grazing intensity was an important determinant of clover content in years 2 and 3, where hard grazing resulted (P<0.05) in higher clover content. Digestibility of the herbage on offer ranged from 65 to 80%, and crude protein concentrations varied from 12 to 26%. In general, frequent grazing resulted in a digestibility of 2–4 percentage units higher than infrequent grazing, with hard grazing also tending to increase digestibility. Hard grazed treatments always had high crude protein concentrations in the herbage present before grazing, and there was a slightly higher concentration in frequently grazed herbage compared with herbage that was grazed less frequently. The white clover–perennial ryegrass swards generally responded best to a combination of frequent and hard grazing. However, neither white clover nor perennial ryegrass appears to be well adapted to the combination of soils, climate, irrigation and grazing by dairy cows that occurs in the northern irrigation region of Victoria, as evidenced by a rapid influx of weeds and the general decline in productivity over the duration of the experiment.

Author(s):  
V.T. Van Vught ◽  
E.R. Thom

The persistence of an endophyte-free ryegrass (Lolium perenne L.) pasture established by autumn spray/drilling was studied over two years at the Dairying Research Corporation, Hamilton. Main plots were sprayed with glyphosate at 1.44 kg a.i./ ha (4 l/ha of Roundup G2) in mid March 1996 (S), or mid March and again in mid April (D). White clover (Trifolium repens L.) was removed from half the area of each main plot using herbicide and the remainder was drilled with white clover. All plots were direct drilled with endophyte-free peren-nial ryegrass in late April. Plots were rotationally grazed by dairy cows. Double spraying killed germinating volunteer ryegrass, Poa species and weeds, almost doubling the ryegrass content of D compared with S plots in the first winter/spring, and maintaining an advantage over the first year from drilling. Plants were larger in D than S over the first winter/spring, contributing to about a 10% improvement in their survival, reducing to about 5% by March 1998. Sown-plant densities were 200-250/m2 by April 1998, similar to those found in high-endophyte pastures. Double spraying reduced the clover content of +Cl plots to similar levels as those in -Cl plots, lowering the potential herbage accumulation for D. Double spraying before drilling had a transitory effect on seasonal herbage accumulation, and no effect on overall herbage accumulation. Keywords: dairy pastures, endophyte, persistence, plant competition, ryegrass, tillering, white clover


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

A whole-farm systems comparison of combinations of perennial ryegrass and white clover cultivars rotationally grazed by dairy cows over two complete seasons evaluated improvements in perennial ryegrass and white clover cultivars resulting from plant breeding efforts. There were four treatments comprised of two ryegrass mixtures and two clover mixtures in a 2 x 2 factorial design, each replicated three times in a randomised block design giving 12, self-contained 4-ha farmlets each stocked at three multiparous Friesian cows/ ha. All pastures were sown in April 1998, using seed obtained through commercial sources, with a high endophyte (>70% endophyte infection) specification for the ryegrass cultivars. A grow out test, carried out after sowing, showed that two of the ryegrass cultivars used in the mix of older cultivars (80R) had less than 70% endophyte infection (Ellett 50%, Nui 62%, Yatsyn 94%) resulting in an average endophyte infection of 69% for that mix. The mix of newer ryegrass (98R) cultivars had an average endophyte infection of 92% (Aries HD 91%, Bronsyn 98%, Samson 87%). While seedling densities (ryegrass and clover) were similar for all mixtures at the start, from late summer of the first year onward, tiller densities were around 30% lower (due to predation of endophyte-free plants and tillers by the Argentine stem weevil) in the 80R treatment. The lower tiller density opened up the sward at an opportune time for clover expansion, which the newer clover cultivars (98C) Sustain and Challenge converted into a higher clover production than from the older clover cultivars (60C) Huia and Pitau. The 80R treatment had a greater spring surplus requiring more conservation than the 98R treatment, which had a more even growth distribution over the year. Differences in endophyte infection levels had a major impact on pasture composition, especially clover content; reducing the endophyte level of seed sown from 90% to 70% may create an opportunity to increase the clover content and quality of young pastures in the Waikato. Keywords: cultivars, dairying, endophyte, perennial ryegrass, tiller density, white clover


Author(s):  
D.A. Clark ◽  
C. Matthew ◽  
J.R. Crush

An upper limit to productivity of perennial ryegrass-white clover pastures in New Zealand at about 15 t DM/ha per year has been identified as a constraint to future increases in productivity. With potential yields of 26.6 t DM/ha per year from temperate grasses and 45 t DM/ha per year from maize at mid-latitudes, the challenge for New Zealand dairy farming systems is to achieve greater than 15 t DM/ha per year without imposing additional production or environmental costs. Given these constraints a major switch to crops is not feasible because those that produce more than pasture, e.g., maize, have insufficient crude protein to support lactation. Theoretically, a farm area allocation to 78% perennial ryegrass-white clover and 22% maize-winter oats could provide 23.3 t DM/ha per year at a crude protein content of 16%. This is greater than the 20 t DM/ha per year upper limit of irrigated perennial ryegrass-white clover. Incremental yield improvements of grasses and clovers by traditional plant breeding are low (1.5% per year), and difficult to capture. Future plant breeding gains are more likely to come from increased plant stress tolerance. Improved pasture monitoring to allow timely removal of constraints, will enable potential yields to be achieved. Biotechnology offers the possibility of improving the potential yield of net photosynthesis by 20% either through the transfer of genes from a C4 plant (e.g., maize) or a C3 plant (e.g., perennial ryegrass), or use of the major photosynthetic enzymes, rubisco, from a thermophilic alga. Biotechnology is also providing new knowledge about the control of plant development and response to stresses. The application of this knowledge may allow dairy farmers to achieve another 5 t DM/ha per year from perennial ryegrass-white clover pastures. Keywords: biotechnology, dairy, perennial ryegrass, photosynthesis, white clover, yield limitation


2003 ◽  
Vol 140 (2) ◽  
pp. 151-159 ◽  
Author(s):  
T. A. WILLIAMS ◽  
D. R. EVANS ◽  
I. RHODES ◽  
M. T. ABBERTON

Three experiments were carried out to investigate the dry matter production of nine white clover (Trifolium repens L.) varieties grown with the same variety of perennial ryegrass (Lolium perenne L.) and subjected to rotational grazing by sheep over a period of 10 years. The experiments differed only in the nitrogen fertilizer added: no nitrogen, 100 kg/ha per year and 200 kg/ha per year. Dry matter (DM) yields of white clover and perennial ryegrass components of the sward were recorded at approximately 6-week intervals during the growing season.Without applied nitrogen, 10-year mean white clover annual DM yields ranged from 2·89–4·54 t/ha. Mean clover content for all varieties ranged from 31–50% for the first 9 years, declining to 20% in the 10th year. The most consistently high yielding variety, AberVantage, gave yields greater than 3·5 t/ha in every year. Similar results were observed for the variety Aran. The 10-year mean annual DM yield of the perennial ryegrass companion (variety Talbot) ranged from 4·41–5·57 t/ha depending on the white clover variety in the mixture. Variation in perennial ryegrass DM yield was of a similar range and pattern as for white clover.In the experiment in which 100 kg N/ha per year was added, 10-year mean white clover annual DM yields ranged from 2·27–3·87 t/ha. The varieties AberVantage and Aran showed yields that fell below 3 t/ha per year in only 1 or 2 years, respectively. Mean clover content for all varieties ranged from 26–38% for the first 9 years, declining to 17·5% in the 10th year. There was no consecutive annual decline in white clover DM yields. The 10-year mean annual DM yields of the perennial ryegrass companion ranged from 6·03–7·57 t/ha.With applied nitrogen fertilizer of 200 kg N/ha per year (Experiment 3), 10-year mean white clover annual DM yields ranged from 1·21–2·67 t/ha. Mean clover content ranged from 12–27% for the 10 years. AberVantage and Aran showed yields consistently above 2 t/ha. No general decline in white clover DM yields was observed although some varieties showed consecutive annual reductions in years 8, 9 and 10. The 10-year mean annual DM perennial ryegrass yields ranged from 7·27–8·68 t/ha.The results show that, under rotational grazing by sheep, white clover can give reliably high yields over a 10-year period. With moderate to high applications of nitrogen fertilizer white clover yields were lower than without nitrogen but they were consistent and sufficient to make a considerable impact on forage quality. There was no evidence for a general decline in clover content until the 10th year of the experiment and no cyclical pattern of annual variation in white clover yield was observed. The implications of these results for the role of white clover in UK agriculture are discussed.


1972 ◽  
Vol 79 (2) ◽  
pp. 291-301 ◽  
Author(s):  
D. Reid

SUMMARYThe yield results are reported for the final 3 years of a 6-year experiment in which twenty-one rates of nitrogen fertilizer ranging from 0 to 800 lb/acre (897 kg/ha) were applied annually on S. 23 perennial ryegrass swards with and without S. 100 white clover. The long-term effects of the treatments on herbage yields are discussed using the results from all 6 years. Four-parameter exponential curves fitted to the herbage yield data from each year show that the response pattern for the pure-grass sward remained relatively constant over the years although the mean annual yields varied slightly. The response of dry-metter yield to nitrogen rate on this sward was almost linear between the 0 and 300 lb nitrogen/acre (336 kg/ha) rates, then it decreased progressively, becoming non-significant about the 500 lb/a ere (560 kg/ha) ra te. Crude-protein yield responded almost linearly up to the 600 lb/acre (673 kg/ha) rate. The average yield responses over the 6 years for the pure-grass sward with nitrogen rates between 0 and 300 lb/acre was 27–8 lb dry matter (range 25·8–29·8 lb) and 4·2 lb crude protein (range 3·8–4·8 lb) per lb of nitrogen applied. At high nitrogen rates the yield curves for the grass and clover sward were similar to those for the pure-grass sward but at low rates the grass and clover sward gave a lower response to nitrogen and a greater yield at each nitrogen rate. The yield response to nitrogen rates between 0 and 300 lb/acre applied on this sward increased from 13·1 lb dry matter/lb of nitrogen in the first year to 20·2 lb in the sixth year. The difference in yield between the grass and clover and the pure-grass swards given no nitrogen fertilizer decreased from 4850 lb dry matter/acre (5440 kg/ha) to 2370 lb/acre (2660 kg/ha) over the same period. Within each year the yield difference between the two swards decreased with increasing nitrogen rate reaching an insignificant value at a rate of about 350 lb/acre (392 kg/ha) in the first year declining to 150 lb/acre (168 kg/ha) in the sixth year. On average the weight of nitrogen required annually on the pure-grass sward to give the same herbage yield as the grass and clover sward receiving no nitrogen was 125 lb/acre (140 kg/ha) on a drymatter basis and 195 lb/acre (219 kg/ha) on a crude protein basis.


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


Author(s):  
Numan Kılıçalp ◽  
Mustafa Avcı ◽  
Hatice Hızlı ◽  
Rüştü Hatipoğlu

This research was conducted to determine forage yield, chemical composition, milk yield and milk composition in dairy cattle grazing on pasture established with species and mixtures of Perennial ryegrass (Lolium perenne, Bastion,PR), Orchardgrass(Dactylis glometata, Pizza,OG) and White clover(Trifolium repens, Huia,WC). In this research conducted for two years, the grazing experiment was carried out according to a change over trial design. For this purpose, a total of 6 Holstein Friesian cows (at the 2nd lactation and with an average of 520 ± 26 kg live weight) were used for two periods, each of which consisted of 30 days (8 days of adaptation and 22 days of the basis period). The milk nutritional composition of the animals (dry matter, fat and protein content) was determined in the last three days in the last five consecutive days of each lactation period. The acid detergent fiber (ADF) content of pasture obtained from Perennial ryegrass + White clover mixture (PRWC) was found to be lower than that obtained from the other two (PR and OG) pasture and Net Energy Lactation (NEL) content was found higher in the first grazing period in the first year. However, the effect of the investigated pastures on milk yield was not significant, but it was found that the effects on milk protein yield in the first year and dry matter of milk in the second year were significant. In the first year of grazing period, milk yield, milk fat yield and protein yield were found to be significant. The results of this study showed that under these operating conditions, the botanical composition of the pasture had no effect on the amount and composition of the milk, but the milk yield decreased as the vegetation period advanced.


2020 ◽  
Vol 60 (1) ◽  
pp. 143 ◽  
Author(s):  
Bríd McClearn ◽  
Trevor Gilliland ◽  
Clare Guy ◽  
Michael Dineen ◽  
Fergal Coughlan ◽  
...  

Grazed grass is considered the cheapest feed available for dairy cows in temperate regions, and to maximise profits, dairy farmers must utilise this high-quality feed where possible. Recent research has reported that including white clover (Trifolium repens L.) in grass swards can have a positive effect on milk production. The aim of the present study was to quantify the effect of tetraploid and diploid perennial ryegrass (Lolium perenne L.; PRG) swards sown with and without white clover on the milk production of grazing dairy cows. Four grazing treatments were used for the study; tetraploid-only PRG swards, diploid-only PRG swards, tetraploid PRG with white clover swards and diploid PRG with white clover swards. Thirty cows were assigned to each treatment and swards were rotationally grazed at a stocking rate of 2.75 cows/ha and a nitrogen-fertiliser application rate of 250 kg/ha annually. There was no significant effect of ploidy on milk production. Over the present 4-year study, cows grazing the PRG–white clover treatments had greater milk yields (+597 kg/cow.year) and milk-solid yield (+48 kg/cow.year) than cows grazing the PRG-only treatments. This significant increase in milk production suggests that the inclusion of white clover in grazing systems can be effectively used to increase milk production of grazing dairy cows.


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