scholarly journals Nitrogen use on Canterbury dryland pastures

Author(s):  
J.D. Morton ◽  
S.D. Mcbride

Results from the first two years of a farmlet trial carried out on a dryland Lismore soil near Ashburton, Mid Canterbury are reported. Farmlet treatments were 0, 25 (25 N) and 50 (50 N) kg N/ha applied as urea in mid-April of 1992 and 1993. Stocking rates for each farmlet were 9.5, 10.5 and 11.5 (Year l), and 11, 12 and 13/ha Borderdale ewes/ha (Year 2). For both years of the trial, there were small increases in mean pasture cover from N use despite the higher stocking rates on the N farmlets. Both mean clover content (14%) and N fixation rates (36 kg N/ha/year) were low but only declined slightly with N use. Average lamb carcass weight was lower on the 25 N and 50 N farmlet than the nil N farmlet (16.9 cf 18.3 kg). Despite this decrease, lamb carcass production per ha was significantly higher on the 50 N farmlet (216 kg/ha) compared with the nil N farmlet (199 kg/ha), Similar wool weights per ewe between farmlets resulted in an increase in wool production per ha from both N farmlets (25 N - 34.9 kg/ha, 50 N - 38 kg/ha) compared to nil N (30.8 kg/ha). Keywords: clover content, lamb production, nitrogen fertiliser, nitrogen fixation, stocking rate, wool production

Author(s):  
S.T. Morris ◽  
A.F. Mcfrae

This paper reports and discusses the results of 4 years of trials (1985-1988) involving 2 farmlets, one receiving 3 nitrogen applications (50 kg /ha) in autumn, winter and spring (+N) and one receiving no N fertiliser (-N). Stocking rags were 3.3 animals/ha on -N farmlet and 4.3 animals/ha on the +N farmlet for the first 3 years, with the objective being to utilise the extra N-boosted grass with extra animals/ha but not to sacrifice individual animal performance. In the fourth year the stocking rates were kept the same on each farmlet (3.3 animals/ha) in an endeavour to utilise the extra grass grown on the +N farmlet by way of increased per head performance. In 2 of the 3 years (1985 and 1987) where the +N farmlet supported the higher stocking rate, liveweight gain (LWG) did not differ between animals. In 1986 the extra animals on the -l-N farmlet had a lower LWG, whereas in 1988 the LWGs were similar for the 2 farmlets stocked at the same rate. The apparent DM responses (kg DM/kg N applied) ranged from 2 to 12. The rates of N fertiliser used in this trial do not appear to result in economic increases in pasture production for the beef production system reported here. Nitrogen fertiliser did not reduce the clover content of pastures rotationally grazed by beef cattle. Keywords beef production, nitrogen fertiliser, pasture composition, livewieght gain, economics.


Author(s):  
R.A. Moss

Lamb meat production from an irrigated old ryegrass pasture farmlet is reported for the following conditions in successive years:- Year 1 and 2: Stocked at 18 ewes plus 5 ewe replacements/ha - dry summers Year 3: Same stocking rate as year 1 - moist summer Year 4: Stocking rate reduced to 15 ewes plus 4 replacements/ha - dry summer Year 5: Same stocking rate as year 4 - wet summer Mean carcass weight for all lambs in years l-5 was respectively 12.0, 12.4, 13.4, 12.0 and 14.2 kg; lamb meat production was respectively 241, 257, 252, 214 and 262 kg/ha. At high stocking rates, in the years with dry summers, early drafting of light weight lambs was necessary so that other lambs could achieve a target carcase weight of 13-16 kg. However ewe lambs did not reach that target. For two years with reduced stocking rate, dry summer weather in one of these years still precluded ewe lambs from reaching the target. In the other year with wet summer weather, production per lamb and per hectare was satisfactory. Further management means of increasing production of heavy weight lamb are discussed. Keywords: Pasture yields, lamb production, carcase weight, wool production


Author(s):  
S.L. Harris ◽  
J.W. Penn ◽  
A.M. Bryant

High rates of nitrogen (N) fertiliser (217 and 324 kg N/ha/y) applied during a farrnlet study at No. 2 Dairy, DRC, Hamilton increased annual net herbage accumulation by 23% and 27% respectively. Increases in feed conservation and milk production reflected the extra pasture growth. On low stocked (3.2 cows/ha) farmlets where 219 and 330 kgN/ba/yr were used, clover contents declined to 12.5% and 3.4% respectively compared with 22.8% where no N was used. Decreased clover content was probably a result of competition from increased growth of ryegrass. At the high stocking rate (4.5 cows/ha), N application resulted in clover contents of 19.6% and 7.9% respectively, compared with 23.8% where no nitrogen was used. Pasture utilisation was better on these fannlets than under the lower stocking rate, suggesting the improved utilisation of additional feed, particularly during spring, was responsible for the higher clover content. Nitrogen fixation activity was lower in pastures which received N fertiliser due to both the decreased clover content and a reduction in activity per clover plant. Keywords: conservation, dairying, milk production, nitrogen fertiliser, pasture production, Trifolium repens


1977 ◽  
Vol 28 (1) ◽  
pp. 133 ◽  
Author(s):  
JP Langlands

Grass and milk consumption and liveweight changes of lambs grazed at stocking rates ranging from 9 to 35 sheep/ha were measured during a 105 day lactation. Grass consumption and wool production of their mothers and of similar ewes without lambs were also determined. The forage and total organic matter intakes of the lamb increased with time while milk consumption declined; all three variables were negatively correlated with stocking rate. The intake of the ewe and its liveweight gain were not sensitive to increasing stocking rate, but wool production declined at higher stocking rates. The maintenance requirement of the ewes was estimated to be 218 kJ metabolizable energy/kg liveweight, and the efficiency with which metabolizable energy was utilized for milk production was 66%. Lactation increased the intake of the ewe but reduced its wool production.


1975 ◽  
Vol 15 (73) ◽  
pp. 159 ◽  
Author(s):  
PA Kenney ◽  
IF Davis

A study was made during a three year period (1 968-1 970) of wool production by a flock of 540 ewes grazing annual pasture at Werribee, Victoria. The ewes were stocked at three rates (5, 7 1/2 and 10 ewes ha-1) and lambed between July 6 and August 20 or between September 10 and October 29 each year. Fibre diameter and length of wool samples were measured in 1968, 1969 and 1970 ; in 1970 growth of greasy wool was calculated from staples of dye-banded wool. Wool growth was reduced in all ewes during late pregnancy and early lactation but was not affected during late lactation in ewes lambing in September. The proportion of tender fleeces from all ewes was greater in 1970 and the weight of fleeces from only those ewes bearing single lambs was less in all years for ewes lambing in July than for ewes lambing in September. More ewes were barren and fewer ewes had twins in July and consequently the mean fleece weights of all ewes from both groups were similar. Fleeces from ewes stocked at 10 ha-1 were lighter, shorter and finer than fleeces from ewes stocked at 5 and 7 1/2 ha-1, but the proportion of tender fleeces did not differ between the groups. Wool production of ewes stocked at 5 and 7 1/2 ha-1 increased from 1968 to 1970, whereas that of ewes at 10 ha-1 did not. This was associated with differences in pasture availability and composition. At 10 ewes ha-1 less pasture was present in winter and spring in 1970 than in 1968, whereas at the other stocking rates it was greater. In 1970 the density of weeds in autumn was greater and in spring more silver grass (Vulpia spp.) and less brome grass (Bromus spp.) was available at the high stocking rate.


1974 ◽  
Vol 14 (69) ◽  
pp. 454
Author(s):  
DJ Cannon

The wool production and liveweight of Corriedale wethers was measured when both stocking rate and the proportion of land to wheat and pasture varied. The nominal stocking rates (R) were 6.8, 8.6, 10.5, 12.4 and 14.2 wethers ha-1, and the proportion sown to wheat was 0, 15 or 30 per cent. Clean wool production per head declined linearly with increase in stocking rate and the proportion of land sown to crop. Generally both maxima and minima liveweights declined with increase in cropping and minima liveweights with increase in stocking rate. The effect of cropping on wool production was attributed to the increased stocking rate on the uncropped portion of land during the period when the cropped area was unavailable to grazing. 'Average' stocking rates per ha (S) were calculated on the basis of the proportion of land to crop and the fraction of the year stubbles were available for grazing. S was found to be a more useful measure of stocking rate than R, in a system of dual use of land.


1974 ◽  
Vol 14 (69) ◽  
pp. 454
Author(s):  
DJ Cannon

The wool production and liveweight of Corriedale wethers was measured when both stocking rate and the proportion of land to wheat and pasture varied. The nominal stocking rates (R) were 6.8, 8.6, 10.5, 12.4 and 14.2 wethers ha-1, and the proportion sown to wheat was 0, 15 or 30 per cent. Clean wool production per head declined linearly with increase in stocking rate and the proportion of land sown to crop. Generally both maxima and minima liveweights declined with increase in cropping and minima liveweights with increase in stocking rate. The effect of cropping on wool production was attributed to the increased stocking rate on the uncropped portion of land during the period when the cropped area was unavailable to grazing. 'Average' stocking rates per ha (S) were calculated on the basis of the proportion of land to crop and the fraction of the year stubbles were available for grazing. S was found to be a more useful measure of stocking rate than R, in a system of dual use of land.


1986 ◽  
Vol 8 (1) ◽  
pp. 46 ◽  
Author(s):  
RD Graetz

Measurements were made of the wool growth, body weight gain and diet of sheep grazing a saltbush pasture near Broken Hill, N.S.W. The experiment utilized a fenceline contrast in saltbush (Atriplex vesrcarra) density that was visible on Landsat imagery. It ran for five years (1976-1981) with a design of two pasture types by two stocking rates. Fleece weights varied from 3.9-6.0 kg/head and wool production from 0.6-2.9 kg/ha. Neither wool production per head nor bodyweight were substantially affected by stocking rate or pasture type. The composition and quality of the diets selected by sheep on both pastures were identical and of high nutritional value indicating their capability to accommodate differences in pasture composition. Pasture quality was not limiting between stocking rates or determined by the abundance of saltbush. Changes in pasture composition resulting from grazing and exclosure were small and of no significance.


1976 ◽  
Vol 27 (6) ◽  
pp. 881 ◽  
Author(s):  
JG Mulholland ◽  
JB Coombe ◽  
M Freer ◽  
WR McManus

The production of young crossbred wethers grazing oat, barley and wheat stubbles was measured in each of three years at stocking rates ranging from 15 to 30/ha. In one year, production on 'weedy' stubbles was compared with that of 'clean' (weed-free) stubbles, and also the effect of a wheat–urea–mineral supplement on the production of sheep was measured on oat stubble. Liveweight change and wool production were significantly influenced by the availability of green plant material and by stocking rate, but not by supplementation. The maximum liveweight loss in any year was 7.5 kg and the maximum gain 6.0 kg, both recorded over 11 weeks' grazing. Mean daily clean wool production was 9.9 g/sheep at the lower stocking rate and 6.6 g/sheep at the higher rate, but production per hectare was 10–60% higher at the heavier stocking rate. The ranking of the crop stubbles with respect to animal production was not consistent from year to year. Intense selection for green plant material by sheep resulted in the proportion of green in the diet being nearly always greater than 80%, when the weight of this material on the plots was more than 40 kg dry matter/ha. It appeared that a low intake of nitrogen was not the main limitation to animal production. A maximum of only 36% of the crop residue which disappeared during the experiment could be accounted for as animal intake. Thus it is unlikely that the potential of cereal residues as a source of food for animal production will be realized with grazing sheep.


Author(s):  
P.C. Luscombe

The effect of N fertiliser on pasture yields and species composition, and spring stock carrying capacity was measured undergrazing at Ballantrae, the Grasslands Division hill country area. N fertiliser was applied as urea in early spring at rates up to 100 kg N/ha. Paddocks were set stocked with sheep with additional sheep being added to N fertilised paddocks to maintain similar herbage availabilities. N fertiliser increased pasture growth by an average of 7 kg DM/ kg N applied. Stock carrying capacities over spring ranged from 18 sheep/ ha without N, to 26 sheep/ ha with 100 kg N/ha. The major species composition effects of N was a reduction in clover yields and clover nitrogen fixation rates, in the spring, summer and autumn after the spring application. Clover growth and N fixation decreased most over summer when clover yields and nitrogen fixation were 41% and 52% lower respectively on hill slopes, at the highest rate of N fertiliser. Pasture yields were lower in autumn on pastures previously N fertilised.


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