Plant and animal production of an irrigated annual pasture following initial gypsum treatment of a heavy clay soil

1970 ◽  
Vol 10 (42) ◽  
pp. 36 ◽  
Author(s):  
LF/Squires VR Myers

The response of an irrigated annual pasture to gypsum (calcium sulphate) was assessed in terms of pasture yield and animal production on a heavy clay soil (Riverina clay). Gypsum was either broadcast (4480 lb an acre) before sowing or dissolved (560 lb an acre) in the water at the first irrigation. Both methods of application increased seedling emergence and pasture production. In the first year of grazing at seven sheep per acre the untreated pasture barely survived, whereas the treated pastures were satisfactory. After four years of grazing, spring yields of the untreated pastures equaled gypsum treated pastures, but only when the stocking rate of the controls had been reduced by three sheep per acre for nearly 18 months. The proportion of sown species was still lower than on treated pasture. The large differences in pasture production were reflected in liveweight gains and wool production an acre. In the final phases stocking rates of five sheep per acre on untreated plots and eight sheep per acre on the gypsum treated plots gave the same production per sheep. An estimate of costs and returns from wool alone indicated that an initial gypsum treatment was profitable.

1997 ◽  
Vol 37 (7) ◽  
pp. 755 ◽  
Author(s):  
R. J. Jones

Summary. Pasture production and steer liveweight gain were compared on native pasture (Bothriochloa decipiens, Heteropogon contortus, Themeda triandra and Chrysopogon fallax) and on native pasture oversown with Indian couch or Indian bluegrass (Bothriochloa pertusa). This grass was not a planned introduction to the area but is spreading in Central and North Queensland and its value as a pasture species is questioned by graziers. There were 3 nominal stocking rates of 0.3, 0.6 and 0.9 steers/ha. Each paddock was stocked with 3 steers of stratified ages. The experiment was sown in March 1988 and terminated in June 1993. The experiment, sited 50 km south of Townsville in eucalypt woodland on a solodic-solodised-solonetz soil, was sown in March 1988 and terminated in June 1993. Increases in stocking rate resulted in a linear decline in both pasture yield (by 3–5 t/unit increase in stocking rate) and steer gains (by more than 100 kg/unit increase in stocking rate). Differences between pastures were apparent only at the medium and high stocking rates where, over time, Indian couch gave higher pasture yields and steer gains. Younger steers gained far more weight than older steers. Mean gains over 3 years were weaners 125 kg/year, yearlings 93 kg/year and 2-year-old steers 46 kg/year. Native pasture remained fairly stable botanically at the low stocking rate, but the tufted perennial grass species declined at both the medium and high stocking rates. Sowing Indian couch hastened the botanical changes due to stocking rate, and it became the dominant species at these higher stocking rates. At the low stocking rate, the contribution of Indian couch declined from initial values indicating that this is not an invasive species in the area at a low stocking rate. Contribution of Indian couch to pasture yield was linearly related to stocking rate. Nutritional quality of the Indian couch was similar to the other native perennial grasses though calcium concentration was higher. Increased steer gains were related to higher yield on Indian couch pastures at the higher stocking rates rather than to improved quality. Maximum liveweight gain/ha was achieved at about 0.6 steers/ha. Stocking at 0.9 steers/ha was not sustainable. Even at the low stocking rate, steers would need to spend about 2.8 years on the pastures after weaning to reach 500 kg liveweight. It was concluded that B. pertusa is a useful pasture grass in this environment giving steer gains equal to, or higher than, the gains from the native pasture which it replaced.


1976 ◽  
Vol 16 (79) ◽  
pp. 209 ◽  
Author(s):  
GG Robinson ◽  
A Lazenby

The species frequency, pasture availability and animal production on natural pastures oversown with white clover were examined over the five year period 1968-73. Superphosphate was applied annually at different levels (0, 250 and 500 kg ha-1) and the plots were grazed continuously at two stocking rates (7.8 and 15.6 wethers ha-1). An increase in the frequency of white clover (Trifolium repens) and a decrease in bare ground, Panicum spp-Eragrostis spp. and Sporobolus elongatus (in the case of the latter two the effect was particularly evident at the low stocking rate) followed the application of superphosphate. Increasing stocking rate resulted in a reduction in white clover and an increase in the frequency of Panicum spp.-Eragrostis spp. and bare ground. Pasture availability and animal production were increased by superphosphate. Apart from the first year, when the season was unusually dry, supplementary feeding was minimal on all topdressed treatments but was essential at the high stocking rate where no superphosphate was applied. Over the five year period animals on the pastures receiving superphosphate averaged 15 per cent heavier and gave 18 per cent more wool than those that were unfertilized. Wool production at the high stocking rate averaged 17.8 kg ha-1 (49 per cent) more than that from the low stocking rate.


1968 ◽  
Vol 71 (3) ◽  
pp. 327-335 ◽  
Author(s):  
J. B. Owen ◽  
W. J. Ridgman

SUMMARYExperiments designed to assess differences between treatments in pasture productivity as measured by the production of animals are complicated by the stocking rates chosen. The paper attempts toderive a simple model relating production per animal and production per unit area to stocking rate for meat animals, based on biological considerations.A method is proposed which would allow meaningful grazing experiments to be carried out employing only one stocking rate, thus considerably reducing the expense of this type of experimentation.The model is applied to some recent data obtained by Hodgson (1966) and Appleton (1967, personal communication).


1978 ◽  
Vol 29 (1) ◽  
pp. 103 ◽  
Author(s):  
LA Edye ◽  
WT Williams ◽  
WH Winter

The relationship between stocking rate and liveweight change per animal was examined over a period of 3 years for two continuously grazed pastures, one of Brachiaria and the other consisting of guinea grass with Endeavour stylo and Siratro. On an annual basis there was no significant effect of stocking rate over the last 2 years, but on a seasonal basis there were highly significant effects in all seasons. In the dry seasons, animal gain rose as the stocking rate fell, but in the last two wet seasons gains fell with the lower stocking rates. On an annual basis the two effects cancelled out. Response surfaces for gain versus pasture yield and stocking rate were curvilinear (quadratic) during the wet season and linear during the dry. Optimum stocking rates (for maximum gain per hectare) were determined for the wet and dry seasons; the rate was greatly affected by the yield of green material during the dry season but less so during the wet. The possible causes of this reversed wetseason effect are discussed.


1978 ◽  
Vol 18 (95) ◽  
pp. 788 ◽  
Author(s):  
NH Shaw

Changes in the yield, botanical composition and chemical composition of a native pasture (Heteropogon contortus dominant) oversown with S. humilis (T.S.) were measured in a grazing experiment from 1966 to 1973. The 24 treatments were factorial combinations of two sowing methods for T.S. (ground sowing into spaced cultivated strips, or aerial sowing), three levels of molybdenized superphosphate (F0 = nil ; F1 = 125 kg ha-1 annually; F2 = 250 kg ha-1 annually plus an extra 250 kg ha-1 initially) and four stocking rates. Stocking rates were gradually increased during the experiment and for the last three years overlapping ranges were used for the three fertilizer levels; the overall range was then from 0.55 to 1.65 beasts ha 1 T.S. establishment by ground sowing was much more reliable than from aerial sowing, giving twice the average percentage frequency, and this proportion was maintained over years. High fertilizer improved establishment and the best legume stands were in the high fertilizer high stocking rate treatments. Total presentation yield of pasture was increased by fertilizer and reduced by high stocking rates. Over the last two years the means for March, adjusted by regression to the overall average stocking rate of 0.98 beasts ha-1, were 31 20,4020 and 5370 kg ha-1 for F0, F1 and F2 respectively, but these yields were reduced by ca 25 per cent for an increase of 0.5 beasts ha-1. H. contortus remained dominant and its mean contribution to total yield increased from 48 per cent in 1969 to 67 per cent in 1973. This proportion was reduced by 12.8 per cent over the range from 0.55 to 1.65 beasts ha-1, but high fertilizer had the opposite effect so that differences between the extremes low stocked F0 and high stocked F2 were small. The DM percentage yield of T.S. was strongly increased by fertilizer, and, most importantly, also by high stocking rates in the presence of fertilizer. Values for F0 treatments remained below 10 per cent, but in the final year values for F1 and F2 at the highest stocking rates were 36 and 27 per cent, respectively. Despite these large changes in T.S., there was overall stability of botanical composition. Phosphorus and nitrogen concentrations in T.S. and H. contortus were increased by superphosphate but there was an overall decline in potassium concentration. Soil phosphorus levels were greatly increased


1993 ◽  
Vol 33 (5) ◽  
pp. 561 ◽  
Author(s):  
CJ Gardener ◽  
MR McCaskill ◽  
JG McIvor

Native pastures dominated by Heteropogon contortus (speargrass) were sown to Stylosanthes hanzata cv. Verano in 1972, and herbage production and steer growth rates were compared with those of native pastures from 1973 to 1985. The native pastures also contained naturalised Stylosanthes humilis, but its contribution to pasture yield diminished rapidly, after infection by Colletotrichum gloeospoirioides (anthracnose) in 1973. The experiment was a factorial design of 2 pasture types (native, native plus Verano) x 2 stocking rates (0.6, 1.2 steers/ha) x 2 superphosphate treatments (nil, 300 kg/ha.year) x 2 replicates. Fertiliser application decreased the proportion of legume but had no significant effect on herbage or animal production on this comparatively fertile site (extractable P, 18 mg/kg). Annual liveweight gains at the high and low stocking rates, respectively, on the native pasture averaged 100 and 120 kg/steer. Sowing to Verano did not affect herbage yields but increased annual liveweight gains by 28 and 36 kg/steer at low and high stocking rates. The high stocking rate of 1.2 steers/ha was sustainable for the first 9 years of the experiment, when above-average rainfall was received. However, in the following 3 below-average years, there was a shift to less-desirable species, and a decline in pasture productivity. Relative to the low stocking rate, herbage production on the native pasture in the final season was reduced by 60% and on the Verano pasture by 26%. The highest annual herbage utilisation rate that appeared sustainable in the long term was about 45%, which corresponded to a utilisation rate of 30% during the growing season (about November-May). When oversown with Verano, speargrass tended to decline in favour of annual grasses, weeds, and the introduced grass Urochloa mosanzhicensis, which had been sown on an adjacent experiment. Urochloa appeared to be a more suitable companion species than speargrass for Verano.


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.


1973 ◽  
Vol 81 (2) ◽  
pp. 193-204 ◽  
Author(s):  
J. P. Langlands ◽  
I. L. Bennett

SummaryA Phalaris tuberosa and Trifolium repens pasture was grazed continuously at stocking rates varying from 2·5 to 37·1 sheep per ha between 1964 and 1969. During this period herbage availability and composition, basal cover, root weight, water infiltration, soil moisture content, bulk density and chemical composition of the soil were measured at intervals.As stocking rate was increased, herbage availability, root weight, basal cover, soil pore space and the rate of water infiltration declined, and bulk density and the nitrogen and calcium contents of the herbage on offer increased. In periods of below-average rainfall, soil moisture and nitrate levels were greater when herbage was of low availability.Herbage production was calculated from estimates of herbage consumption and of litter decomposition, and averaged 8·45 t dry matter/ha/year; it was insensitive to changes in stocking rate over the range from 2 to 22 sheep/ha. The ratio, herbage consumption/ pasture production increased by 0'045 per unit increase in stocking rate.


Author(s):  
K. Milligan

This collection of papers does four significant things: 1. It concentrates on hill country. 2. Precisely defines the research environment in pasture levels and animal production terms. One can clearly see the consequences in animal production at different times of the year when pre-grazing and residual herbage levels are defined and varied and to see the effects of different grazing systems at these pasture levels. Much better than high vs low stocking rates. 3. Attempts to set pature targets as well as animal production targets. 4. Defines critical pasture DM levels both below which pasture production is reduced, and above which control is lost. The proximity to these critical levels will, for a farmer, more precisely define the grazing management system he should adopt and the levels of animal production he should be able to achieve


1982 ◽  
Vol 33 (4) ◽  
pp. 705 ◽  
Author(s):  
BA Rowe

A simple relation between the annual wool production per animal (y) and the amount of pasture dry matter produced per animal (x) was derived and tested using the results from a grazing experiment in which the effects of superphosphate and stocking rate on wool and pasture dry matter production were measured from pastures which were continuously grazed by Merino wethers for 3 years. The linear relation, y = a + b/x, accounted for 63% of the variance in wool production per animal in the first year, 82 % in the second and 97 % in the third. Exclusion of an outlier from the first year results increased the variance accounted for to 85 %. This model is simpler and more precise than some others that have been published. It is also consistent with the curvilinear relation between production per animal (y) and pasture production per animal (x).


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