Productivity of vegetable crops in a region of high solar input. I. Growth and development of the potato (Solanum tuberosum L.)

1973 ◽  
Vol 24 (5) ◽  
pp. 733 ◽  
Author(s):  
PJM Sale
Keyword(s):  
New South ◽  
Solanum Tuberosum L ◽  
High Growth ◽  
Field Capacity ◽  
Vegetable Crops ◽  
South Wales ◽  
Moisture Deficit ◽  
Main Effect ◽  
Growth Analyses ◽  
Bulking Rate

Two spring-planted and one summer-planted crops of the potato var. Scbago have been grown under conditions of high solar input (daily averages throughout each experiment 23.1, 22.2, and 13.9 MJ m-2 respectively) in the Murrumbidgee Irrigation Areas of New South Wales. Treatments were a combination of three levels of solar input (0, 21, and 34% shade throughout growth) with two levels of irrigation (soil restored to field capacity at each estimated soil moisture deficit of 2.0 cm or 3.5 cm in two experiments, 3.5 cm or 5.0cm in the other). Growth analyses were made throughout each experiment. Environmental measurements showed little effect of shade covers on air temperature or relative humidity, and occasional measurements of leaf temperature and leaf water potential showed only small differences between shaded and unshaded plants. Differences in leaf and stem dry weights between plants in any treatments were small, but leaf area and stein length increased and specific leaf weight decreased with increasing shade. An increase in shade also decreased the numbers of tubers per stem which developed, and, while it did not influence the time of initiation, the time between onset of initiation and development of maximum bulking rate was greater as shade increased. Bulking rates with no shade were high (up to 1.4 t ha-l day-l) and only slightly less on shaded plots. In the drier of the two irrigation treatments in each experiment bulking rate was only slightly reduced, but the rate of leaf senescence was greater. The treatments did not affect the time of cessation of bulking. The results are consistent with the hypothesis that photosynthesis in the potato is controlled largely by the size of the 'sink' provided by the growing tubers, and it is suggested that the main effect of solar input was in controlling the 'sink' size which developed in the two or three weeks following the onset of initiation. The high growth rates and accelerated ontogeny were probably largely a result of the high temperatures of the region. Final yields are considered in the next paper.

Field measurements of nitrogenase activity in soils amended with wheat straw

1983 ◽  
Vol 34 (6) ◽  
pp. 725 ◽  
Author(s):  
MM Roper
Keyword(s):  
Nitrogenase Activity ◽  
New South ◽  
Field Measurements ◽  
Field Capacity ◽  
Nitrogen Fertilizers ◽  
Free Living ◽  
Straw Decomposition ◽  
Indirect Measure ◽  
South Wales

Nitrogenase activity and decomposition of straw were examined in situ in two areas (Gunnedah and Cowra) representative of large areas of the New South Wales wheat belt. Measurements of nitrogenase activity were made by adapting the acetylene reduction assay for use in the field. Evolution of CO2 was monitored as an indirect measure of decomposition of straw. The addition of straw to soil stimulated nitrogenase activity which was related to the amount of straw added and the rate of straw decomposition. There were significant levels of activity provided the soil was moist and warm. Nitrogenase activity increased with mean daily soil temperature (up to at least 30�C) and decreased as the soil dried from field capacity. It is concluded that nitrogen fixation by free-living nitrogen-fixing microorganisms in soils amended with straw may contribute to the nitrogen status of the soil and thus reduce the need for nitrogen fertilizers.

Effect of Seedbed on Emergence and Establishment From Surface Sown and Direct Drilled Seed of Eucalyptus Spp. And Dodonaea Viscosa.

1997 ◽  
Vol 19 (1) ◽  
pp. 80 ◽  
Author(s):  
WS Semple ◽  
TB Koen
Keyword(s):  
Woody Plants ◽  
New South ◽  
Similar Degree ◽  
Dodonaea Viscosa ◽  
Factors Affecting ◽  
South Wales ◽  
Main Effect ◽  
Direct Drilling ◽  
Seedbed Preparation ◽  
Herbicide Glyphosate

In some areas the increase of woody plants is a problem whereas in others, the lack of regeneration is viewed with a similar degree of concern. The experiments described in this paper were an attempt to further understand factors affecting regeneration of woody plants. The effect of seedbed on the emergence and survival of hopbush (Dodonaea viscosa ssp. angustissima) and on several species of Eucalyptus was evaluated at two sites in the Central West of New South Wales. Seed was sown in two springs, two summers and two autumns from 1990 to 1992 and seedlings monitored for 12 months after sowing. Seedbeds compared were prepared by cultivation, scalping, burning, applying herbicide (glyphosate) and mowinglgrazing (control). Following failure of surface sowing in spring 1990 and summer 1990191 due to poor seasonal conditions, all subsequent experiments included direct drilled controls. Emergents were recorded in most treatments in the four succeeding seasons but hopbush and eucalypts responded differently to treatments. Numbers of hopbush emergents and seedlings after 12 months were consistently higher following direct drilling into scalped seedbeds. In contrast, the maximum number of eucalypt emergents was not consistently associated with any seedbed type, though emergence was generally higher following direct drilling. However, higher numbers of eucalypt seedlings were present in scalped plots after 12 months. It was concluded that weed control following emergence was the main effect of seedbed preparation on the number of eucalypt seedlings present after 12 months. Though this also applied to hopbush. seedbeds which provided the opportunity of seed burial enhanced emergence. This was believed to be due to the breaking of seed dormancy.

Development of a low-cost pupal release strategy for Sterile Insect Technique (SIT) with Queensland fruit fly and assessment of climatic constraints for SIT in rural New South Wales

2000 ◽  
Vol 40 (7) ◽  
pp. 1021 ◽  
Author(s):  
B. C. Dominiak ◽  
L. J. McLeod ◽  
R. Landon ◽  
H. I. Nicol
Keyword(s):  
New South ◽  
Low Cost ◽  
New South Wales ◽  
Adult Emergence ◽  
Fruit Fly ◽  
Rural Environment ◽  
Ant Predation ◽  
South Wales ◽  
Moisture Deficit ◽  
Release Strategy

Sterile pupae of Queensland fruit fly (Qfly) Bactrocera tryoni (Froggatt) were released to suppress wild Qfly populations at 3 sites in New South Wales and to assess a pupal release strategy using the bed technique. Sterile pupae were released from September 1997 to June 1998 from sand and vermiculite beds. A total of 24.6 million pupae were released with a male recapture rate of 0.101% (not corrected for adult emergence rate). Adult emergence rates were 25% at Tullibigeal; 39% at Ungarie and 46, 41, 71 and 54% respectively at 4 locations at Lake Cargelligo (mean 46%). Corrected recapture rates using cue-lure traps were 0.88% at Tullibigeal, 0.08% at Ungarie and 0.15% at Lake Cargelligo (mean 0.21%). When wild fly populations increased at Lake Cargelligo, a bait spraying program was used which substaintially reduced the catches of both sterile and wild flies in traps. Analyses using the CLIMEX model showed that the climate at Lake Cargelligo town (with irrigation) was suitable for fruit flies. CLIMEX indicated that the unmodified rural environment was unsuitable for fruit fly survival due to a summer moisture deficit. The Meats daily survival rate decrement of 58–72% was similar to that found for some similar studies in Australia but lower than for certain other release programs. No significant bird or ant predation was observed.

The growth of three tropical pasture grasses on the mid-north coast of New South Wales

1975 ◽  
Vol 15 (76) ◽  
pp. 637 ◽  
Author(s):  
DR Kemp
Keyword(s):  
New South ◽  
New South Wales ◽  
Irrigation Treatment ◽  
Growth Curves ◽  
High Growth ◽  
North Coast ◽  
Seasonal Growth ◽  
South Wales ◽  
Pasture Grasses ◽  
Kikuyu Grass

The yields and seasonal growth curves of kikuyu grass, (Pennisetum clandestinum) setaria, (Setaria anceps cv. Kazungula) and broadleaf paspalum (Paspalum wettsteinii), were determined over a three year period at Taree (lat. 32�s) New South Wales with or without irrigation and under nil, 170 or 680 kg N ha-1 yr-1 (nil, low and high N). Annual forage yields averaged 1300, 51 00 and 13,000 kg DM ha-1 at nil, low and high N respectively. Kikuyu grass yields were significantly less than setaria or broadleaf, especially at low N. Both the apparent recovery of nitrogen and the efficiency of dry matter production by kikuyu grass were less than the other grasses. Yields from the irrigated plots were similar to the dryland plots due largely to a generally favourable rainfall pattern. During short dry periods the extra yield from irrigation was less than from the application of nitrogen. The patterns of seasonal growth were similar for each species at any one nitrogen rate and irrigation treatment. The growing season (>5 kg DM ha-1 day-1) without nitrogen, was only four to six months, commencing in late spring. This was increased to eight months at low N (October to May) and nine months (September to May) with high N. The mean period of high growth rates (>60 kg DM ha-1 day-1) over summer was nil at nil N, only six days at low N but increased to 154 days at high N. Winter growth was negligible.

The effect of calcium and soil pH on nodulation of T. subterraneum L. clover on a yellow podsol

1950 ◽  
Vol 1 (4) ◽  
pp. 374 ◽  
Author(s):  
D Spencer
Keyword(s):  
Moisture Content ◽  
Soil Ph ◽  
New South ◽  
New South Wales ◽  
Subterranean Clover ◽  
Field Capacity ◽  
Pot Experiments ◽  
South Wales ◽  
Calcium Supply

The mechanism of the action of lime in stimulating nodulation of subterranean clover on some soils of the Southern Tablelands of New South Wales was studied in pot experiments. Increased soil pH or increased calcium supply alone did not markedly improve nodulation. With a combination of both these factors, excellent nodulation resulted. Nodulation was shown to be increased by increasing the amount of the inoculum of Rhizobium added with the seed. It was also increased if the moisture content of the soil was maintained continually at field capacity.

Managing the weaning transition of Merino lambs by promoting positive growth rates and increasing survival – is yard weaning a viable option?

2012 ◽  
Vol 52 (7) ◽  
pp. 516 ◽  
Author(s):  
S. Gabb ◽  
S. Hatcher ◽  
J. Eppleston ◽  
B. Watt ◽  
K. J. Thornberry
Keyword(s):  
Growth Rates ◽  
Transition Period ◽  
Production Systems ◽  
New South ◽  
High Growth ◽  
Control Group ◽  
Economic Costs ◽  
South Wales ◽  
Positive Growth ◽  
Group Variable

The effectiveness of yard weaning to manage the weaning transition period for Merino sheep was investigated on three commercial properties in the New South Wales Central Tablelands. Three experiments were conducted, Experiment 1 investigated the duration of yard weaning, Experiment 2 compared two alternative rations provided to yard-weaned animals, while Experiment 3 compared yard weaning with paddock weaning. The ‘Control’ for each of the three experiments was each producers’ normal paddock-weaning strategy with comparisons based on post-weaning growth rates and weaner survival. Liveweights were recorded at weaning and at 15, 50 and 180 days post-weaning. Growth rates were calculated from liveweight measurements. Survival was determined by the continuing presence of an individual animal at subsequent measurements. Compared with the paddock-weaned Control group, variable responses in liveweight, growth rates and weaner survival to 50 and 180 days post-weaning occurred in the three experiments. Yard weaning was not superior to any of the producers’ normal paddock-weaning practices, however, favourable seasonal conditions in early 2010 prompted high growth rates in the paddock-weaned Control animals relative to those achieved by the yard-weaned animals. Further research is required to determine the optimum duration of confinement and ration (including composition and method of delivery). This work should include comparisons of the behaviour of paddock- and yard-weaned animals and model production benefits versus economic costs for a range of production systems and market scenarios.

Phytophthora drechsleri Tucker and Pythium spp. as pathogens of safflower in New South Wales

1973 ◽  
Vol 13 (63) ◽  
pp. 455 ◽  
Author(s):  
G Stovold
Keyword(s):  
Root Rot ◽  
New South ◽  
New South Wales ◽  
Field Capacity ◽  
Pythium Ultimum ◽  
Carthamus Tinctorius ◽  
Pythium Myriotylum ◽  
Pythium Irregulare ◽  
South Wales ◽  
Phytophthora Drechsleri

Pythiaceous fungi associated with a widespread root rot disease of safflower (Carthamus tinctorius) in New South Wales include Phytophthora drechsleri, Pythium myriotylum, Pythium ultimum Pythium irregulare, Pythium acanthicum, and a number of sterile Pythium spp. Pathogenicity of these fungi was tested against safflower seedlings and older plants growing either in soil with moisture content at field capacity or in flooded soil. Phytophthora drechsleri, Pythium myriotylum, Pythium ultimum and Pythiumirregulare caused severe pre-emergence damping off. When safflower plants, three and eight weeks old, were inoculated with each of the fungi, only Phytophthora drechsleriand Pythium myriotylum killed a high proportion of plants. The pathogenicity of Phytophthora drechsleri, Pythium myriotylum, Pythium ultimum, and Pythium irregulare was increased by flooding the soil for ninety hours after inoculation. Phytophthora drechsleri was isolated from naturally infected saffron thistle (Carthamus lanatus). Cross inoculation tests with Phytophthora drechsleri isolates from safflower and saffron thistle showed that both isolates could infect each host. Saffron thistle could be an important alternative host of Phytophthora drechsleri in the field. It is concluded that Phytophthora drechsleri is the major cause of root rot of safflower in New South Wales.

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