Seasonal trends and variability of soil moisture under temperate pasture on the Northern Tablelands of New South Wales

1975 ◽  
Vol 15 (73) ◽  
pp. 250 ◽  
Author(s):  
RCG Smith ◽  
GG Johns

A water balance model predicting changes in soil moisture under temperate pasture at Armidale, New South Wales was developed and tested against soil moisture measurements made from 1967 to 1969. The model accounted for 96 per cent of the variance in observed soil moisture. The model was then used to predict the expected pattern of soil moisture for this area using daily Armidale rainfall data from 1878 to 1973 and pan evaporation data from 1951 to 1970. Expected soil moisture levels rise to a maximum in late winter and then progressively decline to a minimum in mid summer. Levels may increase again slightly during late summer but remain low through autumn before beginning to rise again during winter. On the basis of this analysis it is suggested that the safest time to establish new plant species into temperate pasture is probably early winter when expected soil moisture begins to rise rapidly. Because of the autumn deficiency in soil moisture it was concluded that fodder oats grown in this period would often be inhibited by a lack of soil moisture unless preceded by a fallow to conserve late summer rainfall. The need for soil moisture data in interpreting and extrapolating from field experiments is stressed.

1989 ◽  
Vol 40 (3) ◽  
pp. 605 ◽  
Author(s):  
KA Archer ◽  
GG Robinson

This paper reports the findings of a five-year study on the growth patterns, production and means of persistence of white clover in a cool temperate environment with summer dominant rainfall, on the Northern Tablelands of New South Wales. White clover essentially persisted as a perennial, but large and rapid declines in plant frequency occurred during late summer if soil moisture levels became depleted. The critical combination of conditions at which plant frequency was adversely affected occurred when available soil moisture levels declined below 35 mm and mean weekly maximum temperatures exceeded 20�C; conditions which often occur in late summer in this environment. During one prolonged period of moisture stress in the second spring and summer period of the study, all plants died. Regeneration was due to germination of seeds and seedling establishment, but plants subsequently persisted as perennials. Relationships were developed to predict the probability of survival of white clover over the range of temperatures and soil moistures recorded in these experiments. Germination occurred to a variable extent each year, but was observed only during winter and spring. Seedling establishment was effective in only one year, which followed the death of white clover in summer, 1980-81. The sward was slow to recover after seedling regeneration owing to low winter temperatures and competition from established temperate perennial grasses in spring. Seedlings contributed little to dry matter production in spring. These results indicate that white clover is unlikely to be of value as an annual in temperate pastures. Strategies aimed at improving white clover in cool temperate environments, either by management or selection/breeding programs, should therefore focus upon improving the ability of white clover to persist as a perennial.


1976 ◽  
Vol 16 (83) ◽  
pp. 871
Author(s):  
PM Dowling ◽  
RCG Smith

The objective of this study was to determine the time of year that maximized establishment and . minimized the risk of failure in aerial sowing of pasture seed on the Northern Tablelands of New South Wales. This was achieved by relating a set of monthly measurements of establishment spanning two years to mean soil moisture, predicted by a water balance model for the six-week period following sowing. From this relationship, establishment was simulated for 61 years using historical rainfall data to estimate probability density functions of establishment for each week of the year. From these functions it was concluded that maximum establishment with minimum risk can be expected from sowing in the June-July period. For perennial species plant survival over the first summer is of more practical importance than per cent establishment. Our data on plant survival, although not presented, indicated a close relationship existed between establishment and survival and supported the conclusion that the optimal time for oversowing is June-July.


1976 ◽  
Vol 16 (83) ◽  
pp. 871
Author(s):  
PM Dowling ◽  
RCG Smith

The objective of this study was to determine the time of year that maximized establishment and . minimized the risk of failure in aerial sowing of pasture seed on the Northern Tablelands of New South Wales. This was achieved by relating a set of monthly measurements of establishment spanning two years to mean soil moisture, predicted by a water balance model for the six-week period following sowing. From this relationship, establishment was simulated for 61 years using historical rainfall data to estimate probability density functions of establishment for each week of the year. From these functions it was concluded that maximum establishment with minimum risk can be expected from sowing in the June-July period. For perennial species plant survival over the first summer is of more practical importance than per cent establishment. Our data on plant survival, although not presented, indicated a close relationship existed between establishment and survival and supported the conclusion that the optimal time for oversowing is June-July.


2001 ◽  
Vol 41 (7) ◽  
pp. 971 ◽  
Author(s):  
R. W. Dicker ◽  
J. F. Ayres ◽  
M. J. McPhee ◽  
D. L. Robinson ◽  
A. D. Turner ◽  
...  

This paper describes the post-weaning growth of Bos taurus and Bos taurus x Bos indicus-derived steers grazing temperate perennial pasture in northern New South Wales. These cattle were either autumn weaners from spring-calving herds in summer rainfall environments, or summer weaners from autumn-calving herds in winter rainfall environments. Autumn weaners were grown out on 3 pasture systems: (i) pasture only (P1), (ii) pasture supplemented in late winter–early spring with formulated pellets of high protein content (P2), or (iii) pasture supplemented with a nitrogen-fertilised forage crop (P3) to provide different growth pathways towards entry to the finishing phase. Over the 3-year study, seasonal liveweight gain on P1 varied between –0.21 and 1.05 kg/head.day; liveweight gain was generally low (about 0.5 kg/head.day) in winter and high (about 0.8 kg/head.day) in spring. Bos taurus autumn weaners achieved feedlot entry specifications for the domestic market (300 kg liveweight) in 6–8 weeks by the end of winter, and feedlot entry specifications for the export market (400 kg liveweight) in 17–27 weeks by the end of summer. For B. taurus x B. indicus-derived autumn weaners, the period to feedlot entry was 19 and 33 weeks for domestic and export feedlot entry specifications, respectively. Supplementary feeding generally increased post-weaning growth in late winter–early spring and reduced the period to feedlot entry for export steers. Summer weaners were grown out on pasture in P1, P2 or P3 pasture systems, met domestic feedlot entry specifications on arrival, but did not reach export feedlot entry specifications before the onset of winter imposed liveweight stasis. The most effective grow-out system was based on Bos taurus autumn weaners with supplementary feeding in winter–spring to overcome the limitations of the winter feed gap.


1978 ◽  
Vol 18 (94) ◽  
pp. 648 ◽  
Author(s):  
H Hawker ◽  
JP Kennedy

At Fowlers Gap, an arid saltbush environment in far western New South Wales, the wool growth of South Australian Merino ewes was measured at intervals of about ten weeks for three years. Highest rates of wool growth on dry ewes were recorded each year in late winter (1 0.8, 14.9, 15.7 g day-1) and lowest in late summer (6.0, 7.7, 10.7 g day-1). Changes in the rate of wool growth were associated with changes in pastoral conditions in two of the three years. Relative to dry ewes, the rate of wool growth of wet ewes was reduced by 9 to 24 per cent in late pregnancy, 21 to 43 per cent in early lactation and 3 to 26 per cent in late lactation. The reduction was inversely related to current pasture growth.


1969 ◽  
Vol 9 (41) ◽  
pp. 610 ◽  
Author(s):  
EC Wolfe ◽  
FC Crofts

The seasonal productivity of eight perennial grasses at three nitrogen levels was measured in small pure-grass swards at Badgery's Creek, New South Wales. Highly significant differences in seasonal productivity were found between nitrogen levels in all four seasons, and between cultivars in summer, autumn, and winter. The response of the grasses to nitrogen was slightly greater at the high than at the medium level of nitrogen application in all seasons, and was highest in spring (about 40 lb of dry matter per lb of applied nitrogen) and lowest in mid-winter (about 8 lb/lb). Tall fescue was the most efficient responder to nitrogen in late summer and early autumn, Kangaroo Valley ryegrass in late autumn and late winter, and Currie cocksfoot in mid-winter. At a high level of nitrogen, the dry matter produced by Kangaroo Valley ryegrass and Currie cocksfoot in the late autumn to early spring period, the period of greatest feed shortage, was nearly as great as that produced over a similar period by sod-sown oats in earlier experiments at Badgery's Creek.


2011 ◽  
Vol 62 (12) ◽  
pp. 1067 ◽  
Author(s):  
L. G. Gaynor ◽  
R. J. Lawn ◽  
A. T. James

The response of irrigated soybean to sowing date and to plant population was evaluated in field experiments over three years at Leeton, in the Murrumbidgee Irrigation Area (MIA) in southern New South Wales. The aim was to explore the options for later sowings to improve the flexibility for growing soybean in double-cropping rotations with a winter cereal. The experiments were grown on 1.83-m-wide raised soil beds, with 2, 4, or 6 rows per bed (years 1 and 2) or 2 rows per bed only (year 3). Plant population, which was manipulated by changing either the number of rows per bed (years 1 and 2) or the within-row plant spacing (year 3), ranged from 15 to 60 plants/m2 depending on the experiment. Two sowings dates, late November and late December, were compared in years 1 and 3, while in year 2, sowings in early and late January were also included. Three genotypes (early, medium, and late maturity) were grown in years 1 and 2, and four medium-maturing genotypes were grown in year 3. In general, machine-harvested seed yields were highest in the November sowings, and declined as sowing was delayed. Physiological analyses suggested two underlying causes for the yield decline as sowing date was delayed. First and most importantly, the later sown crops flowered sooner after sowing, shortening crop duration and reducing total dry matter (TDM) production. Second, in the late January sowings of the medium- and late-maturing genotypes, harvest index (HI) declined as maturity was pushed later into autumn, exposing the crops to cooler temperatures during pod filling. Attempts to offset the decline in TDM production as sowing was delayed by using higher plant populations were unsuccessful, in part because HI decreased, apparently due to greater severity of lodging. The studies indicated that, in the near term, the yield potential of current indeterminate cultivars at the late December sowing date is adequate, given appropriate management, for commercially viable double-cropping of soybean in the MIA. In the longer term, it is suggested that development of earlier maturing, lodging-resistant genotypes that retain high HI at high sowing density may allow sowing to be delayed to early January.


1992 ◽  
Vol 32 (4) ◽  
pp. 447 ◽  
Author(s):  
G Sweeney ◽  
RS Jessop ◽  
H Harris

The yields and yield structure of cultivars of triticales and bread wheats (with a range of phasic development patterns in both species) were compared in 2 field experiments at Narrabri in northern New South Wales. The experiments were performed on a grey cracking clay soil with irrigation to prevent severe moisture stress. Triticales, both early and midseason types, appeared to have reached yield parity with well-adapted wheat varieties. Meaned over the 2 experiments and all sowings, the triticales yields were 19% greater than the bread wheats. Triticales were generally superior to wheat in all components of yield of the spike (1000-grain weight, grain number/spikelet and spikelet number/spike), whilst the wheats produced more spikes per unit area. The triticales also had higher harvest indices than the wheats. The results are discussed in relation to the overall adaptability of triticale for Australian conditions.


1994 ◽  
Vol 34 (1) ◽  
pp. 33 ◽  
Author(s):  
GM Lodge

Burrs were collected from paddocks on 3 properties in northern New South Wales where the age of the Trifolium subterraneum var. brachycalycinum cv. Clare swards varied from 19 to 28 years. At 1 site burrs were also sampled from swards sown 2 and 10 years previously. Twenty seedlings from these burrs and 20 plants of certified cv. Clare were grown as spaced plants in a nursery. These were assessed for vegetative and floral characters, flowering time, number of seeds per burr, seed weight, and percentage hardseed after storage at 25/25�C for 6 months and 25/45�C for a further 6 months. For most plants the mean number of days from sowing to first flower was similar to that of Clare. Compared with the naturalised strains, Clare had the lowest (P<0.05) mean number of seeds per burr: about 25% below the mean of the strains (2.7 seeds per burr). While the lowest mean seed weights of the strains were not significantly different from those of Clare, the seed weights of plants from 3 sites were higher (P<0.05) than those of Clare. After storage for either 6 or 12 months, hardseed levels were also lowest (P<0.05) for Clare. Plants from the 2-year-old sward had the same median number of seeds per burr (2.0) as Clare. As sward age increased, the median number of seeds per burr increased to 2.8. Hardseed percentages were lowest for plants of Clare and for those from the 2-year-old sward after 6 months, and for Clare after 12 months. These studies indicated the presence of divergent strains in old swards of Clare in a summer rainfall environment. Natural selection among variability within Clare is the most likely reason for the development of these strains in an environment marginal for the long-term persistence of this softseeded cultivar. Although strains had the same vegetative and floral markings as Clare, differences in ecologically important characters such as number of seeds per burr, seed weight, and hardseededness may result in plants that are better adapted to the environment in which they evolved. From these studies 23 plants of T. subterraneum var. brachycalycinum were selected for further evaluation.


1974 ◽  
Vol 14 (71) ◽  
pp. 790 ◽  
Author(s):  
JV Lovett ◽  
EM Matheson

In field experiments conducted over three years at Armidale, New South Wales, the total winter forage production by barley, oats, wheat and rye was similar. However, barley and rye tended to outyield wheat and oats at early harvests, the reverse applying at late harvests. It is suggested that these characteristics of the cereals could be exploited to meet specific seasonal requirements for dry matter production more effectively than is possible with a single species. Response to high seeding rates in forage production was similar in all cereals and was confined to a late sowing. Significant differences in in vitro digestibility over the winter period were recorded and differences were also apparent in subsequent grain yield.


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