Evaluation of management options for increasing the productivity of tropical savanna pastures. 2. Legume species

1989 ◽  
Vol 29 (5) ◽  
pp. 623 ◽  
Author(s):  
WH Winter ◽  
JJ Mott ◽  
RW McLean
Keyword(s):  
Perennial Grasses ◽  
Legume Species ◽  
Forage Production ◽  
Wet Season ◽  
Management Options ◽  
Stylosanthes Humilis ◽  
Northwestern Australia ◽  
Animal Growth ◽  
Townsville Stylo ◽  
Stocking Rates

The effect of legume species, used for augmentation of native perennial grasses, upon forage production and quality and animal production was studied over 4 vears in the semi-arid troPics of northwestern Australia. The legumes were Stylosanthes humilis cv. Paterson (Townsville stylo), S. hamata cv. Verano (Caribbean stylo) and a mixture of perennial species S. scabra cvv. Fitzroy and Seca and S. viscosa (perennial stylo). They were compared at 2 levels of fertility, unfertilised (UF) and with small inputs of superphosphate (F); and at stocking rates of 0.45,0.6 and 0.75 steers/ha for UF and 0.6, 0.8 and 1.0 steers/ha for F. By 1980 only half of the 3 x 12 treatments persisted, 3 Townsville stylo, 9 Caribbean stylo and 6 perennial stylo. Without fertiliser the perennial stylos had the highest wet season yields of 1-2 t/ha which constituted 4040% of pasture yield, compared with 2-20% for the other legumes. Caribbean stylo yields were highest with fertiliser, yielding 2-4 t/ha and 50-90% of the pasture at the end of the wet season, compared with 60-70% for perennial stylo and 5-30% for Townsville stylo. Anthracnose devastated Townsville stylo, and also reduced the productivity of Fitzroy. The perennial stylos had the highest concentrations of nitrogen (N), phosphorus (P), and sulfur (S) during the dry season while Caribbean stylo and its associated grasses had the lowest P and S concentrations during the wet season. When annual liveweight gains for each legume were compared at the same stocking rate-fertiliser level, differences were less than 15 kg, but there were considerable differences in the patterns of growth within the year; these differences were related to the seasonal availability and relative palatability of grass and legume. The overall mediocre animal growth of 30-110 kg/steer.year was attributed to the inadequate supply of nutrients for most of the year, with the possible exception of N.

Evaluation of management options for increasing the productivity of tropical savanna pastures. 1. Fertiliser

1989 ◽  
Vol 29 (5) ◽  
pp. 613 ◽  
Author(s):  
WH Winter ◽  
JJ Mott ◽  
RW McLean ◽  
D Ratcliff
Keyword(s):  
Nitrogen Concentration ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Low Fertility ◽  
Stocking Rate ◽  
Wet Season ◽  
Management Options ◽  
Themeda Triandra ◽  
Stylosanthes Humilis ◽  
Stocking Rates

Options for increasing pasture and animal production from native perennial pastures comprising predominantly Themeda triandra, Chrysopogon fallax, Sehima nervosum and Sorghum plumosum were studied over 5 years at Katherine in the semi-arid tropics of north-western Australia. The pastures were augmented with either Stylosanthes humilis, S. hamata or a mixture of S. scabra and S. viscosa, either without fertiliser or with low inputs of superphosphate (100 kg/ha at establishment and 25 kg/ha annually), and with the trees either killed or left undisturbed. At each fertiliser level there were 3 stocking rates. Five years after sowing, only half of the pastures persisted, due to the poor productivity of the legumes and the inability of the native perennial grasses to tolerate high grazing pressure which was about 10-fold that for non-augmented native pasture. This effect was greater in the unfertilised treatments, where the legume contributed less to pasture yield, so that the sustainable stocking rate was only half of that for pastures fertilised with small amounts of superphosphate. When fertilised, stable pastures of nearly pure legume were obtained after 3-4 years at the highest stocking rate of 1 steer/ha. Fertiliser also (i) increased the nitrogen and sulfur concentrations of S. humilis and the perennial stylos S. scabra and S. viscosa, but lowered their concentrations in S. hamata, particularly in the early wet season; (ii) decreased nitrogen concentration in Chrysopogon fallax; and (iii) increased phosphorus and sulfur concentrations of all the perennial grasses. In general, fertiliser promoted higher liveweight gains of cattle during the wet season and lower losses during the dry season. In the fertilised treatments growth tended to be poorer at the highest stocking rate, particularly during the late dry and early wet seasons. This effect was attributed to spoilage of dry legume by the early rainfall and lack of grass in these treatments. We conclude that S. hamata, S. scabra and S. viscosa grow reasonably well in soils of low fertility, but the productivity of the legumes and of the cattle can be improved by small inputs of superphosphate. The mediocre growth of the cattle in all the treatments may have been due to the low levels of some nutrients, particularly phosphorus and sulfur, in these pastures.

Evaluation of management options for increasing the productivity of tropical savanna pastures. 3. Trees

1989 ◽  
Vol 29 (5) ◽  
pp. 631 ◽  
Author(s):  
WH Winter ◽  
JJ Mott ◽  
RW McLean
Keyword(s):  
Dry Season ◽  
Perennial Grasses ◽  
Fertility Level ◽  
Wet Season ◽  
Management Options ◽  
Themeda Triandra ◽  
Weight Losses ◽  
Nitrogen Concentrations ◽  
The Mean ◽  
Stocking Rates

The effect of killing trees upon the production and quality of native perennial grasses, Themeda triandra, Chrysopogon fallax, Sehima nervosum, and Sorghum plumosum, and oversown legumes from the genus Stylosanthes, was studied over 4 years at Katherine, in the semi-arid tropics of northwestern Australia. The pastures were either unfertilised or received low inputs of superphosphate, and for each fertility level were grazed at 3 stocking rates. At no time were legume yields affected by killing the trees but, in the first 3 years, the amount of grass was approximately twice as much when the trees were killed. During this period the mean grass yields declined 4-5 fold from about 2.2 t/ha. By the fourth year the advantage from tree killing upon grass yield was apparent only at the lowest stocking rates at each fertility level. Nitrogen concentrations of the grasses and legumes, with the exception of S. hamata, were increased 7 and 10% respectively above the mean annual values of 0.89 and 1.75% where the trees were killed, while the phosphorus and sulfur concentrations were not affected. Tree killing had no effect upon wet season liveweight gains during the last 2 years of the experiment. However, there were some benefits during the dry season when weight losses were lower for most treatments during the early dry season (June-September) and also lower for the lowest stocking rate treatment without fertiliser during the late dry season (October-November).

Wet season grazing of Townsville stylo pasture at Katherine, N.T

1970 ◽  
Vol 10 (47) ◽  
pp. 710 ◽  
Author(s):  
MJT Norman ◽  
LJ Phillips
Keyword(s):  
Dry Matter ◽  
Correlation Coefficients ◽  
Dry Matter Yield ◽  
Stocking Rate ◽  
Wet Season ◽  
Nitrogen Yield ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Using Data ◽  
Stocking Rates

At Katherine, N.T., stocking rates of 1.33, 1.00, and 0.67 Shorthorn steers an acre for a period of 18 weeks in the wet season beginning January were imposed on established pastures sown to Townsville sty10 (Stylosanthes humilis) alone but subsequently invaded to varying degrees by annual grasses. The experiment was repeated over three years. There were no significant differences in mean liveweight gain per head over three years ; hence liveweight gain per acre at the heaviest stocking rate was approximately twice that at the lightest rate. The mean dry matter yield of grass increased significantly with decreasing stocking rate, but there were no significant differences between stocking rates in Townsville stylo dry matter yield, nitrogen yield, or phosphorus yield. Correlation coefficients were calculated using data from individual paddocks and years. There was a highly significant positive correlation between liveweight gain per head and pasture nitrogen yield, and between liveweight gain per head and pasture phosphorus yield.

Effect of time of cessation of wet season grazing on Townsville stylo-annual grass pasture at Katherine, N.T

1973 ◽  
Vol 13 (64) ◽  
pp. 544 ◽  
Author(s):  
MJT Norman ◽  
LJ Phillips
Keyword(s):  
Dry Matter ◽  
Recovery Period ◽  
Dry Matter Yield ◽  
Annual Grass ◽  
Wet Season ◽  
Active Growth ◽  
Heavy Grazing ◽  
Stylosanthes Humilis ◽  
Dry Conditions ◽  
Townsville Stylo

A Townsville stylo (Stylosanthes humilis)-annual grass pasture at Katherine, N.T., was subjected to a series of treatments in 1969-70 and 1970-71 under which plots were grazed heavily from the beginning of the wet season for a period and then allowed to recover undefoliated for the remainder of the season. The dates at which heavy grazing ceased were spaced at 2-week intervals from November 24 to March 16. At the end of the wet season, total dry matter yield was linearly related to length of recovery period. Townsville stylo yield declined as recovery period was reduced from 18 to 8 weeks, but showed little response to a further reduction to 4 weeks. In contrast, annual grass yield showed little change as recovery period was reduced from 18 to 8 weeks, but fell with a further reduction to 4 weeks. As a result, the proportion of Townsville stylo in the pasture at the end of the season was high with long and short recovery periods but reached a minimum with an 8 - 10 week recovery period. Dry conditions prevailed in the first half of both seasons. The evidence suggests that young Townsville stylo is sensitive to heavy grazing when under water stress, and that early grazing for grass control should be imposed only during periods of active growth.

Herbicides for weed control in grain sorghum crops in the Northern Territory

1970 ◽  
Vol 10 (46) ◽  
pp. 588
Author(s):  
IMW Wood
Keyword(s):  
Good Control ◽  
Dry Weight ◽  
Grain Sorghum ◽  
Northern Territory ◽  
Research Station ◽  
Wet Season ◽  
Grain Yields ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Grass Weed

In experiments conducted in the 1968-69 wet season at the Katherine Research Station, Northern Territory, a number of herbicides gave good control of the grass weed Pennisetum polystachyon in grain sorghum crops. Linuron at 3 lb a.i. an acre and PCP at 20 lb a.i. an acre as pre-emergence applications effectively controlled grasses with no apparent adverse affects on the crop. With both there were significantly higher grain yields than on unweeded control plots containing an average of 1378 lb dry weight of P. polystachyon an acre. Fluometuron at 3 lb a.i. an acre late pre-emergence and early post-emergence and chlorthal at 7 lb a.i. an acre pre-emergence controlled grasses but did not increase grain yields. Further investigations are warranted with these herbicides, as banded applications to the interrow may overcome the apparent problem of crop phytotoxicity. Chlorthal at rates that gave good grass control had no adverse effect on Townsville stylo (Stylosanthes humilis). This could be an important advantage when sorghum is sown in rotation with Townsville stylo pasture or where the crop is undersown with Townsville stylo.

Effect of pasture type and supplementary feeding on the reproductive performance of cattle in the dry tropics of north Queensland

1977 ◽  
Vol 17 (85) ◽  
pp. 197 ◽  
Author(s):  
RG Holroyd ◽  
PJ Allan ◽  
PK O'Rourke
Keyword(s):  
Reproductive Performance ◽  
Dry Season ◽  
Conception Rate ◽  
Wet Season ◽  
Lactating Cows ◽  
Dry Tropics ◽  
Stylosanthes Humilis ◽  
Native Pasture ◽  
Conception Rates ◽  
Townsville Stylo

A study was made over a four year period ( 1970-1 973) on the reproductive performance of cows grazing either native pasture stocked at 1 breeder 4.9 ha-1 or native pasture oversown with Townsville stylo (Stylosanthes humilis) and fertilized with superphosphate, stocked at 1 breeder 2.4 ha-1. Animals were supplemented on each pasture type with combinations of molasses, urea and phosphorus at various times of the year. Mating from September 1 to January 31 resulted in animals lactating during the dry season. At double the stocking rate, lactating cows on fertilized pastures had similar conception rates to those on native pasture. During a prolonged dry season, lactating cows on fertilized pasture had twice the conception rate and fewer required survival feeding. Urea compared with non-urea based supplements produced significant increases in conception rates of cows grazing native pasture especially during a dry year. Calves were born earlier, had shorter intercalving intervals and fewer cows had to be fed a survival ration when urea was available. On fertilized pasture, urea based supplements caused only a marginal increase in conception rate except in a dry year, when there was a significant increase. Over the four years, there was a diminishing response in the conception rate of lactating cows grazing native pasture and supplemented with phosphorus during the wet season compared with the control. On fertilized pasture, there was a variable but non-significant response. The addition of phosphorus either as a wet or dry season supplement to urea caused variable responses on each pasture type, but none differed significantly from that of urea.

The effect of a phosphorus supplement on the performance of steers grazing Townsville stylo-based pasture in north Queensland

1977 ◽  
Vol 17 (86) ◽  
pp. 357 ◽  
Author(s):  
L Winks ◽  
FC Lamberth ◽  
PK O'Rourke
Keyword(s):  
Dry Season ◽  
Wet Season ◽  
Dry Tropics ◽  
Stylosanthes Humilis ◽  
Native Pasture ◽  
Weight Gains ◽  
Annual Grasses ◽  
Townsville Stylo

The effect of phosphorus supplementation on the performance of steeres grazing unfertilized native pasture and Townsville stylo (Stylosanthes humilis) with andwithout superphosphate fertilizer on the subcoastal spear grass region of the dry tropics of north Queensland was studied over a period of 40 months. Liveweight gains in the absence of supplementation on fertilized Townsville stylo pastures were greater than on unfertilized Townsville stylo, where performance was similar to that recorded on untreated native pasture. Phosphorus supplementation increased weight gains during the wet season on both unfertilized Townsville stylo and native pasture but had no significant effect on dry season performance or performance on fertilized Townsville stylo. Fertilized areas became dominated by annual grasses, Digitaria ciliaris and Brachiaria milliiformis, and legume yields were higher on unfertilized than on fertilized areas. Fertilizer improved the quality of available pastures.

Management options for increasing the productivity of tropical savanna pastures. IV. Population biology of introduced Stylosanthes spp

1989 ◽  
Vol 40 (6) ◽  
pp. 1227 ◽  
Author(s):  
JJ Mott ◽  
WH Winter ◽  
RW McLean
Keyword(s):  
Population Biology ◽  
Large Scale ◽  
Rapid Decline ◽  
Management Options ◽  
Hard Seed ◽  
Long Term Stability ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Fertilizer Rates

In a large-scale grazing experiment in the Monsoon Tallgrass savannas of the Northern Territory, Townsville stylo (Stylosanthes humilis), Caribbean stylo (S. hamata) and perennial stylo (S. scabra + S. viscosa) were sown into native pasture and grazed at three stocking rates, under two fertilizer rates and with trees killed and unkilled. These treatments, together with the occurrence of anthracnose, led to the rapid decline in both yield and numbers of plants in those pastures sown to Townsville stylo. In contrast, yields of Caribbean stylo and Perennial stylo stabilized after three years in both fertilized and unfertilized swards. While total legume yield of these latter two treatments was similar, the dominant contribution in Caribbean stylo was made by annual plants, while in Perennial stylo swards individuals more than 18 months old contributed 80% of the yield.There were marked differences between all species in their population biology. Townsville stylo declined in numbers with death of individuals prior to seed set and the rapid depletion of the soil seed pool which had little long-lived seed. In contrast, in swards of Caribbean stylo a large amount of hard seed rapidly built up in the soil seed pool and ensured continuity of productivity even if seed was not set in some years. In the perennial stylos, seed softened quickly, and the soil seed pool remained small and short-lived. In these latter Stylosanthes spp., long-term stability depended on the survival of perennating plants rather than seed.Pasture management must take into account these different patterns of population dynamics. In particular, while fire is a potentially useful tool in renovating Caribbean stylo swards with their large soil seed pool, it can be extremely detrimental to perennial stylo swards where individuals are susceptible to burning and there is little soil seed available to re-establish the sward.

Improvement in soil structure resulting from sown pastures on degraded areas in the dry savanna woodlands of northern Australia

Soil Research ◽  
1983 ◽  
Vol 21 (1) ◽  
pp. 83 ◽  
Author(s):  
BJ Bridge ◽  
JJ Mott ◽  
WH Winter ◽  
RJ Hartigan
Keyword(s):  
Soil Structure ◽  
Surface Soil ◽  
Northern Australia ◽  
Wet Season ◽  
Stylosanthes Hamata ◽  
Native Grassland ◽  
Townsville Stylo ◽  
Stocking Rates ◽  
High Infiltration

The structure of the surface soil under pastures sown on a former Themada australis native grassland and on degraded areas in the red earths of northern Australia was examined micromorphologically. Heavily grazed pastures containing the legumes Stylosanthes hamata cv. Verano and Alysicarpus vaginalis had more macropore space in the surface soil than arlightly grazed native grassland, while pastures containing S. humilis (Townsville stylo) had as little macropore space as degraded areas. Macropore space in a S. hamata pasture increased between the third and fourth wet seasons after establishment. Where macropore space was high, infiltration measurements showed that sorptivities were as high as those in the native grassland. Where macropore space was low, sorptivities were as low as those in degraded areas. However, all sown pastures showed low hydraulic conductivities equivalent to those in the degraded areas, and this was attributed to trampling during the wet season under the higher stocking rates involved. The improvement and maintenance of soil structure in the S. hamata and A. vaginalis pastures, together with their high sorptivities, indicates that they are stable in the long term.

Effect of stocking rate and fertilizer on the performance of steers grazing Townsville stylo-based pasture in north Queensland

1974 ◽  
Vol 14 (67) ◽  
pp. 146 ◽  
Author(s):  
L Winks ◽  
FC Lamberth ◽  
KW Moir ◽  
PM Pepper
Keyword(s):  
Grass Species ◽  
Stocking Rate ◽  
Native Grass ◽  
Dry Tropics ◽  
Yield And Quality ◽  
Stylosanthes Humilis ◽  
Native Pasture ◽  
Townsville Stylo ◽  
Stocking Rates

The performance of steers grazing Townsville stylo (Stylosanthes humilis)-native grass pasture, with and without superphosphate fertilizer, was studied at two stocking rate (0.41 and 0.82 beasts ha-1) on the sub-coastal spear grass region of the dry tropics of north Queensland over a period of three and a half years. Fertilizer increased yield and quality of pasture, but invasion of the fertilized areas by annual grass species was occurring by the end of the study. Liveweight gains on fertilized Townsville stylo pastures were greater than on unfertilized Townsville stylo, where performance was similar to that recorded on untreated native pasture at stocking rates of 0.25 and 0.41 beasts ha-1. Liveweight gains at the lighter stocking rate were greater than at the higher level on the Townsville stylo-native grass pasture, but at the stocking rates applied to native pasture there was no significant effect of stocking rate. A stocking rate of 0.41 beast ha-1 on fertilized Townsville stylo was safe in all years. Wastage of material was high owing to mould development on the Townsville stylo which remained as standing hay during the winter.

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