The effects of superphosphate on the growth and development of Townsville stylo (Stylosanthes humilis) in pure ungrazed swards at Katherine, NT

1970 ◽  
Vol 10 (47) ◽  
pp. 716 ◽  
Author(s):  
MJ Fisher

The effects of four levels of superphosphate (0, 112, 224, and 448 lb an acre) on the growth and development of ungrazed Townsville stylo (Stylosanthes humilis) in pure swards were examined on virgin Tippera clay loam at Katherine, N.T. Yields and distribution of dry matter, nitrogen, and phosphorus, leaf area, and growth rate, were measured every two weeks. Leaf relative water content and soil water extraction were measured at the end of the wet season. Yield responses to superphosphate were curvilinear and fitted regressions of the form y = a nx + bx + c at all harvests. Superphosphate encouraged root exploitation of the soil volume, but phosphorus deficient swards were more resistant to drought. The maximum recovery of phosphorus was 20, 14, and 14 per cent respectively when 112, 224, and 448 lb an acre superphosphate was applied. Loss of 31 per cent dry matter, 34 per cent nitrogen, and 44 per cent phosphorus in the eight weeks following maximum yield was concluded to be due to translocation to the root system. Even with 448 lb an acre superphosphate the phosphorus content of standing material was below the the critical percentage quoted in the literature as indicating phosphorus sufficiency.


1973 ◽  
Vol 13 (64) ◽  
pp. 544 ◽  
Author(s):  
MJT Norman ◽  
LJ Phillips

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.



1973 ◽  
Vol 13 (63) ◽  
pp. 389 ◽  
Author(s):  
MJ Fisher

A one-year experiment was done in the field at Katherine, Northern Territory, to determine the influence of defoliation at different times (January, February, and March) and heights (5, 13 and 20 cm) on the growth and development of Townsville stylo (Stylosanthes humilis) in ungrazed swards grown with complete fertilizer and irrigation. Townsville stylo withstood repeated defoliation at 5 cm provided that cutting started in January, but, when the first defoliation was delayed, single cuts at 5 cm in either February or March killed 82 and 53 per cent of the swards. Defoliation to 5 cm early in the season reduced total cumulative yield by less than 450 kg ha-1, and did not affect pod yield or nitrogen and phosphorus concentrations at the end of the growing season. Immediately after defoliation nitrogen and phosphorus concentrations were reduced, but there was rapid recovery to higher levels with 5-cm and the same levels with 13-cm defoliation. Successive defoliation at 4 3 cm in February and March increased yield of pods. Defoliation at both 5 and 13 cm increased relative growth rate compared with the control and less frequently defoliated treatments. Defoliation to 5 cm each four weeks altered the stand morphology to a dense mat of foliage at cutting height. The ability of Townsville stylo to withstand continued defoliation suggests that sustained grazing during the growing season may be successful in controlling grass weeds vulnerable to grazing without greatly reducing pod yield or total dry matter production of Townsville stylo.



1970 ◽  
Vol 10 (47) ◽  
pp. 710 ◽  
Author(s):  
MJT Norman ◽  
LJ Phillips

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.



1972 ◽  
Vol 23 (4) ◽  
pp. 633 ◽  
Author(s):  
PJ Robinson ◽  
RK Jones

The effects of phosphorus and sulphur applications on the growth of Townsville slylo (Stylosanthes humilis) and the redistribution of dry matter, nitrogen, phosphorus, and sulphur in various parts of the plant were examined in a glasshouse experiment. Large yield responses lo phosphorus and sulphur, and a highly significant interaction were obtained. Phosphorus and sulphur deficiency caused a 3-week delay in flowering. The rapid decline in nutrient concentrations both before and after flowering is discussed in relation to the use of critical values. Townsville stylo shows a very marked ability to translocate nutrients to the seed. Adequately fertilized plants contained only 0.02% phosphorus and 0.10% sulphur in the mature leaf, while the seeds contained 0.36% phosphorus and 0.36% sulphur. This is discussed in relation to animal nutrition during the dry season.



1974 ◽  
Vol 14 (69) ◽  
pp. 495 ◽  
Author(s):  
JR Ive ◽  
MJ Fisher

Townsville stylo (Stylosanthes humilis) selections collected from twelve naturalized populations, in Queensland and the Northern Territory, and certified seed of the Katherine ecotype ('lines'), were grown for three years in a field experiment at Katherine, N.T. (latitude 14.3�S). In the third year, the experiment was oversown with Digitaria ciliaris. Flowering of all lines was delayed by late sowing, but was hastened by drought. However, the order in which the lines flowered was basically the same for all three years, and similar to that at Lansdown, Queensland (latitude 19.7�S). Although seasonally dependent, highest dry matter production was associated with erect mid- or late mid-season maturity lines which were often lowest in nitrogen and phosphorus concentration. There were no differences between lines in their ability to compete with Digitaria. Grazing reduced the proportion of grass in the swards compared with the forage harvested and non-defoliated treatments largely because Townsville stylo appeared to withstand grazing and trampling better than Digitaria.



1970 ◽  
Vol 10 (47) ◽  
pp. 755
Author(s):  
MJ Fisher ◽  
LJ Phillips

Two experiments were done at Katherine, N.T. to compare the effectiveness of minimum cultivation techniques for establishing both bulrush millet and grain sorghum for stock feed in weedy leys of Townsville stylo (Stylosanthes humilis). Measurements were made of crop yield and regeneration and weediness of the swards after cropping. In the first experiment, tyne cultivation ('chisel ploughing') in the dry season was compared with mouldboard ploughing and rotary hoeing in the wet season and with shallow tyne cultivation ('chisel sweeps') in the early wet season. In the second experiment chisel sweeps in the early wet season and chisel ploughing and rotary hoeing in the wet season proper were used. Crops were established in 6-inch drills and 3-feet rows in both experiments. In the first experiment, chisel sweeps gave yields within 14 to 28 per cent of those obtained by mouldboard ploughing or rotary hoeing, and in the second experiment there were no yield differences between cultivation treatments. Climatological data suggest that no difficulty would be encountered in using chisel sweeps at Katherine in at least three years in five. In the first experiment, establishment technique had no effect on crop yield, but in the second seasonal conditions were more favourable and yield in 6-inch drills was higher than in 3-feet rows. Both crop species completely suppressed the ley and in the second experiment, but not the first, Townsville sty10 content in the year following cropping was 23 per cent greater in the cropped compared with the uncropped treatments. Millet produced more dry matter than sorghum (17420 cf. 13120 lb an acre), but the same nitrogen yield (83.4 lb an acre). In millet 1.2 per cent dry matter and 3.2 per cent nitrogen were in the heads, and for sorghum the figures were 24.8 and 53.7. Sorghum appears to have potential as cattle forage.



2009 ◽  
Vol 60 (6) ◽  
pp. 566 ◽  
Author(s):  
R. F. Brennan ◽  
M. D. A. Bolland

Canola (oilseed rape, Brassica napus L.) is now grown in rotation with spring wheat (Triticum aestivum L.) on the predominantly sandy soils of south-western Australia. For both crop species, fertiliser nitrogen (N) and phosphorus (P) need to be applied for profitable grain production. The fertiliser N requirements have been determined separately for canola or wheat when adequate P was applied. By contrast, the fertiliser P requirements of the 2 species have been compared in the same experiment when adequate N was applied and showed that canola consistently required ~25–60% less P than wheat to produce 90% of the maximum grain yield. We report results of a field experiment conducted at 7 sites from 2000 to 2003 in the region to compare grain yield responses of canola and wheat to application of N and P in the same experiment. Four levels of N (0–138 kg N/ha as urea [46% N]) and 6 levels of P (0–40 kg P/ha as superphosphate [9.1%P]) were applied. Significant grain yield responses to applied N and P occurred for both crop species at all sites of the experiment, and the N × P interaction for grain production was always significant. To produce 90% of the maximum grain yield, canola required ~40% more N (range 16–75%) than wheat, and ~25% less P (range 12–43%) than wheat. For both crop species at 7 sites, applying increasing levels of N had no significant effect on the level of P required for 90% of maximum grain yield, although at 1 site the level of P required to achieve the target yield for both crop species when no N was applied (nil-N treatment) was significantly lower than for the other 3 treatments treated with N. For both crop species at all 7 sites, applying increasing levels of P increased the level of N required for 90% of the maximum grain yield. Fertiliser P had no significant effect on protein concentration in canola and wheat grain, and oil concentration in canola grain. As found in previous studies, application of increasing levels of N decreased oil concentration while increasing protein concentration in canola grain, and increased protein concentration in wheat grain. The N × P interaction was not significant for protein or oil concentration in grain. Protein concentrations in canola grain were about double those found in wheat grain.



1970 ◽  
Vol 10 (46) ◽  
pp. 588
Author(s):  
IMW Wood

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.



1974 ◽  
Vol 14 (67) ◽  
pp. 182 ◽  
Author(s):  
Mannetje L t ◽  
KHLvan Bennekom

A midseason maturity type of Townsville stylo sown at monthly intervals throughout a year in a glasshouse in Brisbane (27�30' south) started flowering from 42 to 76 days after sowing between February and September, with dry matter yields at flowering ranging from 0.05 to 5.82 g/per plant. Sowings between October and January resulted in flowering after 98 to 157 days, with yields ranging from 26.41 to 54.75 g/per plant. Flowering was mainly determined by daylength, although low temperatures during winter delayed inflorescence elongation. Growth after onset of flowering was measured in plants sown in winter, spring and late summer. Plant weights increased after flowering in all sowings. In the spring sowing this consisted entirely of stem and inflorescence, but in the other sowings leaf was formed after onset of flowering as well. Winter and spring sowings gave the highest, late summer sowing the lowest final yields. The main agronomic implication is that sowing early in the growing season is necessary for obtaining a good first year's yield, but that seed production is little affected by sowing date, ensuring good regeneration even in years with a late start of the growing season.



1970 ◽  
Vol 10 (47) ◽  
pp. 790
Author(s):  
IMW Wood

The use of herbicides to control annual grasses in pastures of Townsville stylo (Stylosanthes humilis) was studied at Katherine, N.T. The herbicides chlorthal, trifluralin, benefin, sindone B, and siduron all controlled the annual grasses Digitaria adscendens and Brachiaria ramosa. The outstanding herbicide was chlorthal, which at 6 lb a.i. an acre pre-emergence gave a Townsville stylo dry matter yield of 3250 lb an acre compared with 1130 lb an acre for the unweeded control and 2440 lb an acre for the handweeded control. At maturity there was no grass in the chlorthal plots and 1940 lb an acre in the unweeded control plots. The data suggest that, without defoliation during the growing period, total suppression of Townsville stylo can be expected when the grass population at establishment exceeds 37 per cent of the total plant population.



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