Effect of fertilizer nitrogen, stocking rate and autumn deferment of grazing in association with hay cutting on the root structure of annual pasture species

1976 ◽  
Vol 16 (78) ◽  
pp. 110 ◽  
Author(s):  
JJ Doyle ◽  
MJ Sharkey

Length, weight, branching and chemical composition of roots of barley grass (Hordeum leporinum) and subterranean clover, (Trifolium subterraneum), the main components of a non-irrigated pasture were measured in the fourth year of an experiment on pastures grazed by Corriedale wethers. The grazing treatments were in a factorial design (2 x 2 x 3) replicated three times, with three stocking rates, two levels of nitrogen fertilizer and two methods of management. Grass and clover density was reduced progressively as stocking rate was increased from 10 to 12 to 17 wethers ha-1 but the surviving plants at maturity had vigorous root systems. This performance of annual species contrasts with that of perennial pasture species where root development and root branching may be expected to decline with increase in grazing pressure. Applications of nitrogen fertilizer annually at rates of 0 or 67 kg ha-1 had little effect on density of grasses or clovers but clover roots were lighter and had fewer rhizobia nodules where nitrogen fertilizer had been applied. The management of pasture by deferment of grazing during regeneration was beneficial to clover plants in that their root structure was larger at maturity; similar effects were not evident in grass roots.

1974 ◽  
Vol 25 (4) ◽  
pp. 525 ◽  
Author(s):  
GD Kohn

From 1962 to 1966 an experiment was carried out at the Agricultural Research Institute, Wagga Wagga, N.S.W., with dry Merino sheep on an annual clover-grass pasture, in which the stocking rate and the rates of topdressing with superphosphate were varied. In the first year Trifolium subterraneum (subterranean clover) responded to superphosphate, particularly at the lowest stocking rates. In the following 2–3 years there was a change to Hordeum leporinum Link (barley grass) dominance. A greater amount of subterranean clover persisted over the years on the unfertilized plots than on the fertilized plots. Clover burr on these treatments was associated with better liveweight performance by sheep over the dry summer-autumn period. However, after the autumn rains germinating barley grass on the topdressed plots allowed rapid liveweight gains to be made by the sheep on those treatments. Greasy wool production per head, averaged over four shearings, was 4.81, 4.36 and 3.86 kg at 5, 10 and 15 sheep per ha respectively. Superphosphate had no significant effect on wool production. Liveweights decreased as the stocking rate increased. However, at a given stocking rate, the liveweight changes were influenced by changes in pasture composition induced by topdressing with superphosphate, as much as by total available pasture. It appears that in this clover ley farming area topdressing can be omitted in the pasture phase of a wool production system after 700 kg superphosphate ha-I have been applied to the soil.


1971 ◽  
Vol 22 (1) ◽  
pp. 81 ◽  
Author(s):  
PG Ozanne ◽  
KMW Howes

The applied phosphorus requirement of a pasture sown to subterranean clover was measured with and without grazing. Under moderate grazing pressure, in the year of establishment, the pasture required about 50 % more phosphorus than when ungrazed. In the following season, at a higher stocking rate, the grazed areas needed twice as much phosphorus as the ungrazed to make 90% of their maximum growth. In both years this difference in requirement between stocked and unstocked treatments was present throughout the growing season. Increased phosphorus requirement under grazing is associated with the need for greater uptake of phosphorus under conditions where redistribution of absorbed phosphorus within the plant is prevented by defoliation. It does not appear to be due to effects of defoliation on root size. Nor does it depend on differential light interception or on changes in botanical composition.


1973 ◽  
Vol 13 (63) ◽  
pp. 404 ◽  
Author(s):  
JG McIvor ◽  
DF Smith

Changes in herbage production, dry matter content, nitrogen content and in vitro digestibility of two sown species-subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum) - and five common volunteer species-capeweed (Arctotheca calendula), musky crowfoot (Erodium moschatum), barley grass (Hordeum leporinum), ripgut brome grass (Bromus rigidus) and soft brome grass (Bromus mollis)-were measured throughout their growth cycle. The volunteer species compared favourably with the sown species for these measurements and should be capable of providing nutritious grazing for animals.


1972 ◽  
Vol 12 (59) ◽  
pp. 608 ◽  
Author(s):  
RC Rossiter ◽  
GB Taylor ◽  
GW Anderson

Pasture swards of the annual clovers Trifolium subterraneum (CV. Geraldton), T. hirtum (CV. Kondinin), and T. cherleri (CV. Yamina), and a mixture of all three were sown on a gravelly soil at Bakers Hill, Western Australia, in 1964. All pastures were set-stocked at 5 sheep ha-l from April 1965-April 1968, and at 8 sheep ha-1 from April 1968-March 1970. From 1966 onwards the amount of pasture dry matter on offer in July and September was two to four times as great on the subterranean clover pasture as on rose or cupped clover pastures. Moreover, the subterranean clover pasture resisted invasion by volunteer annuals more strongly. The mixed clover pasture was dominated by subterranean clover by 1966, and remained so thereafter. For the first four seasons of grazing, wool production was consistently higher (on average, 14 per cent higher) on rose clover than on subterranean clover pasture, and slightly lower still on cupped clover. In the fifth season, when grazing pressure was higher than previously, the rose and cupped clovers 'crashed', and subterranean clover produced most wool. We argue that the higher wool production on rose clover during 1965-1969 was due to some factor additional to digestible organic matter intake.


1968 ◽  
Vol 8 (35) ◽  
pp. 702 ◽  
Author(s):  
DF Smith

Mixed swards of barley grass (Hordeum leporinum) and subterranean clover (Trifolium subterraneum) of two densities were grown at two levels of nitrogen. Growth was started at two different times mid- April and mid-May-and at each time half the plots were subjected to moisture stress. The swards were harvested after nine weeks of growth. The survival of clover plants was reduced by an early start, moisture stress and nitrogen addition : much more so than barley grass. The root : shoot ratios of both species were calculated ; both showed some sensitivity to the time of break and moisture stress, and the grass was also affected by the other two factors. Total sward production and the ratios of clover to grass varied widely Grass daminance was favoured by moisture stress or a late break, and both of these factors tended to override the effect of higher soil nitrogen in determining clover-grass balance. Total sward production more dependent on density than any other factor, especially with the later start. Higher nitrogen was effective in boosting production only if the break was early and there was no moisture stress.


1976 ◽  
Vol 16 (83) ◽  
pp. 810 ◽  
Author(s):  
BD Hill ◽  
DG Saville

A grazing experiment was conducted at Cowra, on the western slopes of New South Wales, on a pasture consisting of lucerne (Medicago sativa) and annual species including capeweed (Arctotheca calendula), barley grass (Hordeum leporinum). wimmera ryegrass (Lolium rigidum) and subterranean clover (Trifolium subterraneum) . The performance of Border Leicesterx Merino ewes mated to Dorset Horn rams and the growth of their progeny was compared under rotational and set stocked grazing management systems, with and without a 20 per cent area of lucerne saved for grazing when additional feed was required. There was one stocking rate (8.7 ewes ha-1) in 1966 and two (8.7 ewes ha-1 and 13.0 ewes ha-1) in 1967 to 1969. Rotational grazing decreased the lamb growth rate but increased the number of lambs born. The management system did not affect the body weight or wool production of the ewes. Lucerne was quickly eliminated from the set stocked areas and was greatly reduced in the rotational systems. Capeweed became dominant in the set stocked areas. Saving increased the number of lambs born at the high stocking rate in 1967 to 1969. In 1966 saving reduced lamb growth, ewe body weight and wool growth in the rotational system. The high stocking rate increased wool production per hectare, but decreased the number of lambs born and, in 1967, the lamb growth rate.


1980 ◽  
Vol 20 (107) ◽  
pp. 678 ◽  
Author(s):  
EC Wolfe ◽  
RD FitzGerald ◽  
DG Hall ◽  
OR Southwood

The production and management of weaner steers on two pasture types were studied over 3 years at Wagga Wagga in southern New South Wales. One pasture (LC) was sown with a mixture of lucerne (Medicago sativa) and subterranean clover (Trifolium subterraneum) and the other (C) was sown only with subterranean clover. On each pasture the management treatments were 1.3 and 2.0 steers ha-' in 1975, and 2.1 and 3.0 steers ha-1 in 1976 and 1977, with a grain supplement at the heavier stocking rate in all years. Each year, steers gained more liveweight in February-March or April-May on LC than on C, and this advantage was maintained or increased until slaughter in the following January. The faster growth of steers on lucerne-clover was always associated with an increased supply of green herbage. Annual liveweight gain on LC exceeded that on C by 20-30 kg/head in 1975 and 1977, and by up to 90 kg/head in 1976, when the rainfall pattern was unsuitable for clover growth. Carcases from steers on LC were heavier (all years), covered with a greater depth of fat (1 975 and 1976) and showed better eye muscle development (1 76 and 1977) than those on C. In 1975, neither stocking rate nor supplementary feeding affected liveweight or carcase development. In the following 2 years, increasing the stocking rate from 2 to 3 steers ha-1 reduced annual liveweight gains by 35-40 kg/head. Oat grain supplements (2-3 kg/head day-1 in February-March, June-July and December-January) improved weight gains and carcase quality on both pasture types in 1977, but only on C in 1976


1972 ◽  
Vol 23 (6) ◽  
pp. 1101 ◽  
Author(s):  
HL Davies ◽  
EAN Greenwood

For five years, three rates of ammonium sulphate (N0, N1, and N3: 0, 280, and 840 kg/ha/year) were applied as a split dressing to ,a pasture of Bromus mollis L. and Trifolium subterraneum L. which was continuously grazed by wethers set-stocked at 8.6 and 12.4 sheep/ha. The N0 treatment produced clover dominance, N1 a mixed sward, and N3 grass dominance. The higher stocking rate increased the proportion of clover in the mixed sward. These differences in botanical composition produced three significant effects on the relation between liveweight gain and quantity of green pasture on offer. An increase in the proportion of clover in the sward increased: (1) the quantity of herbage dry matter on offer required for liveweight maintenance; (2) the maximum rate of liveweight gain; (3) the quantity of dry matter on offer at the point of 90% maximum liveweight gain. Regressions of those three parameters on botanical composition accounted for over 90% of the variance. The effects of treatments on liveweight at other times of the year are also described. In the first year of grazing ammonium sulphate increased liveweight, apparently because of increased pasture on offer after emergence. In subsequent years the effect of ammonium sulphate was reversed: liveweight was reduced, and this was associated with lower nitrogen concentrations in, and lower quantities of, herbage produced. Wool elongation rates were greatest in spring and lowest prior to the germinating rains in autumn. Elongation rate was unaffected by stocking rate and only slightly affected by ammonium sulphate. From January to April, greatest elongation occurred on the grass-dominant N3 paddocks; from May to December greatest elongation occurred on the clover-dominant N0 paddocks. The implications of the role of nitrogen fertilizer in relation to sheep production in the winter rainfall regions of Australia are discussed.


2001 ◽  
Vol 41 (8) ◽  
pp. 1109 ◽  
Author(s):  
R. A. Waller ◽  
P. W. G. Sale ◽  
G. R. Saul ◽  
G. A. Kearney

A 4-year field experiment was carried out in south-western Victoria to determine whether tactical stocking might improve perennial ryegrass (Lolium perenne L.) persistence and prime lamb production, compared with the more common practice of continuous stocking. Tactical stocking consisted of variable-length summer, autumn and winter rotations and continuous stocking in spring. The 2 grazing strategies were compared on 2 contrasting pastures: an upgraded pasture, sown with newer cultivars of perennial ryegrass and subterranean clover (Trifolium subterraneum L.) with 26 kg phosphorus/ha.year, and a more typical naturalised perennial ryegrass pasture receiving 6 kg phosphorus/ha.year. Paddocks were grazed by Border Leicester x Merino ewes, which were mated to a terminal sire to lamb in September. The effects of the grazing systems and pasture treatments on ryegrass persistence and pasture botanical composition are presented in this paper. The perennial ryegrass component of the sward decreased from an average mass of 1000 kg dry matter/ha on the upgraded pasture and 400 kg dry matter/ha on the typical pasture in spring 1996 to 100 kg dry matter/ha and <50 kg/ha for the 2 pasture types, respectively, in spring 1998. This occurred irrespective of the grazing system imposed. The decline of ryegrass was attributed to several factors including the very dry 3-year period, summer rainfall events that caused ryegrass buds to break dormancy then die when dry conditions resumed, the gravelly soil type where the experiment was located, and the high grazing pressure used. A number of species became more prevalent in the pastures as the ryegrass disappeared. Silver grass (Vulpia spp.) increased 4–5-fold on all treatments. By the fourth year, barley grass (Hordeum leporinum) and Bromus spp. had increased significantly with tactical stocking compared with continuous stocking. Capeweed (Arctotheca calendula L.) and Erodium spp. increased on both the continuously stocked and upgraded pastures. The subterranean clover component was maintained across all treatments over the 4 years, indicating that tactical stocking did not adversely affect clover persistence. Since ryegrass declined irrespective of treatment, the tactical stocking system used in this study cannot be recommended for improving ryegrass persistence.


2001 ◽  
Vol 41 (8) ◽  
pp. 1099 ◽  
Author(s):  
R. A. Waller ◽  
P. W. G. Sale ◽  
G. R. Saul ◽  
G. A. Kearney

A 4-year field experiment was carried out in south-western Victoria to determine whether tactical stocking might improve perennial ryegrass (Lolium perenne L.) persistence and prime lamb production, compared with the more common practice of year-around continuous stocking. Tactical stocking consisted of variable length summer, autumn and winter rotations and continuous stocking in spring. The 2 grazing strategies were compared on 2 contrasting pastures: an upgraded pasture, sown with newer cultivars of perennial ryegrass and subterranean clover (Trifolium subterraneum L.) with 26 kg phosphorus/ha.year, and a more typical naturalised perennial ryegrass pasture receiving 6 kg phosphorus/ha.year. Paddocks were grazed by Border Leicester x Merino ewes, which were mated to a terminal sire to lamb in September. The effects of the grazing systems and pasture treatments on herbage production and stocking rate are presented in this paper. Herbage production was similar between the treatments, but tactical stocking significantly increased herbage mass during the growing season (P<0.05) compared with continuous stocking. In spring each year, the herbage mass generally exceeded 3000 kg dry matter/ha in tactically stocked paddocks and averaged 500–900 kg dry matter/ha higher than the mass on continuously stocked paddocks. This enabled the year-round stocking rate to be increased by an average of 9% over the 4 years of the experiment. We considered that the stocking rates could not be further increased, despite the higher herbage mass in spring, as stock reduced the dry herbage to a low residual mass by the opening rains in autumn. In contrast, stocking rates averaged 51% higher on the upgraded pasture compared with the typical pasture over the 4 years of the experiment. This indicates that pasture improvement and soil fertility status have a much greater impact on productivity than changes to grazing method. However, tactical stocking was able to increase the sustainability of prime lamb production on upgraded pastures in a dry summer climate, by maintaining herbage cover on the paddocks over the summer–autumn period.


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