Effects of simulated seedling defoliation on growth and yield of cotton in southern New South Wales

2018 ◽  
Vol 69 (9) ◽  
pp. 915 ◽  
Author(s):  
Jianhua Mo ◽  
Sandra McDougall ◽  
Sarah Beaumont ◽  
Scott Munro ◽  
Mark M. Stevens

Early-season leaf loss due to damage by thrips (Thysanoptera: Thripidae) is considered an important issue by Australian cotton growers. To understand the potential impact of early-season leaf loss in the southern region of New South Wales, we investigated the effects of artificial defoliation on cotton growth, maturity timing and lint yield over four seasons (2013–14 to 2016–17) in commercial cotton crops in the Riverina district. Four defoliation scenarios were investigated: (i) complete defoliation, 100% removal of all true leaves from all plants; (ii) partial defoliation by plant, 100% removal of all true leaves from 75% of plants; (iii) partial defoliation by leaf, removal of 75% of leaf area from all individual true leaves on all plants; and (iv) no defoliation. Defoliation was done by hand at the onset of the 2-, 4-, and 6-node growth stages. Defoliated plants were initially shorter than undefoliated (control) plants, but by ~100-days post seedling emergence, height differences were no longer statistically significant in two of the four seasons. Defoliation did not affect the total number of bolls shortly before harvest. However, complete defoliation delayed crop maturity by up to 18 days and partial defoliation by plant delayed crop maturity by up to 8 days. Because of the delays, fully defoliated plants often had fewer open bolls shortly before harvest and yielded significantly less than undefoliated plants in three of the four seasons. A laboratory experiment with caged cotton seedlings showed that weekly introductions of up to10 thrips per seedling (predominantly onion thrips (Thrips tabaci), the most abundant species on cotton in the region) caused significant clubbing in true leaves, but the total leaf area was not significantly reduced at the 6-node stage. Implications of the results for southern cotton integrated pest management are discussed.


2005 ◽  
Vol 45 (4) ◽  
pp. 435 ◽  
Author(s):  
J. L. Cooper

Two forms of biosolids, with and without lime, were applied to acid soils at 2 sites in central New South Wales. Wheat and triticale were then grown on these sites to determine the effect of biosolids on crop growth and yield. The forms of biosolids used were dewatered sewage sludge cake, and N-Viro Soil which is a lime amended sewage sludge. Dewatered sewage sludge cake was applied at rates of 0, 6, 12 and 24 dry Mg/ha, and N-Viro soil at 0, 1.5, 3.0 and 4.5 dry Mg/ha. Biosolids produced grain yield increases of over 50% at both sites, with the largest yield increases at the highest rate of dewatered sewage sludge. Continued cropping at 1 of the sites showed that significant yield increases were still obtained 3 years after the initial application. The addition of lime and N-Viro Soil raised soil pH, and produced small but long lasting yield increases. However, the main benefit of biosolids seems to have come from the nutrients they supplied rather than changes in soil pH.



1994 ◽  
Vol 34 (7) ◽  
pp. 921 ◽  
Author(s):  
DC Godwin ◽  
WS Meyer ◽  
U Singh

Evidence exists that night temperatures <18�C immediately preceding flowering in rice crops can adversely affect floret fertility and, hence, yields. It has been suggested that sterility induced by low temperature is also influenced by floodwater depth and nitrogen (N) rate. In southern New South Wales, low night-time temperatures are believed to be a major constraint to the achievement of consistently high yields. The availability of a comprehensive model of rice growth and yield that is sensitive to this constraint would aid the development of better management practices. CERES RICE is a comprehensive model that simulates the phasic development of a rice crop, the growth of its leaves, stems, roots, and panicles, and their response to weather. It also simulates the water and N balances of the crop and the effects of stresses of water and N on the yield-forming processes. The model has been extensively tested in many rice-growing systems in both tropical and temperate environments. However, the original model was unable to simulate the level of chilling injury evident from yield data from southern New South Wales. This paper reports modifications made in the model to simulate these effects and the evaluation of the model in environments of low night temperature. Inclusion of the chilling injury effect greatly improved the accuracy of estimated yields from treatments in an extensive field experiment. However, additional testing with a wider range of data sets is needed to confirm the international applicability of the modifications.



1984 ◽  
Vol 24 (125) ◽  
pp. 236
Author(s):  
GK McDonald ◽  
BG Sutton ◽  
FW Ellison

Three winter cereals (wheat varieties Songlen and WW 15, triticale variety Satu) were grown after cotton or summer fallow under three levels of applied nitrogen (0, 100 and 200 kg N/ha) at Narrabri, New South Wales. The cereals were sown on August 7, 1980 and growing season rainfall was supplemented by a single irrigation. Leaf area, total shoot dry matter production and ears per square metre were lower after cotton than after summer fallow, while grain yields of cereals sown immediately after cotton were 33% lower than those sown after fallow. Adding nitrogen increased leaf area, dry matter and grain yields of crops grown after cotton and fallow, but significant increases were not obtained with more than 100 kg/ha of applied nitrogen. Crops grown after cotton required an application of 100 kg N/ha for leaf and dry matter production at anthesis to equal that of crops grown after fallow with no additional nitrogen. The corresponding cost to grain yield of growing cotton was equivalent to 200 kg N/ha. The low grain yield responses measured in this experiment (1 8 and 10% increase to 100 kg N/ha after cotton and fallow, respectively) were attributed to the combined effects of late sowing, low levels of soil moisture and loss, by denitrification, of some of the applied nitrogen. The triticale, Satu, yielded significantly less than the two wheats (1 99 g/m2 for Satu c.f. 255 and 286 g/m2 for Songlen and WW 15, respectively), and did not appear to be a viable alternative to wheat in a cotton rotation.



1992 ◽  
Vol 43 (1) ◽  
pp. 29 ◽  
Author(s):  
PJ Ellison ◽  
GM Murray

Development of stripe rust was observed on wheat cultivars that differed in reaction to the disease at the post booting stage of growth over 4 years (1984-1987) at Yanco and Wagga Wagga in southern New South Wales. In 1984, the epidemic began in August and the disease affected up to 20% of leaf area by the booting stage. The disease then ceased to develop in cultivars with moderately resistant or resistant adult plant reaction (APR) to stripe rust, but in susceptible wheats up to 82% of leaf area was affected by early milk stage of growth. The early onset in 1984 was associated with the highest rain in the previous summer-autumn (January-April) of the 4 years. In the other 3 years, the epidemics began laer. Stripe rust did not develop on cultivars with resistant APR, but it affected up to 97% of leaf area of the highly susceptible cultivar Avocet by early milk. The disease was more severe on later sown than early sown Avocet. The apparent rates of infection both before and after booting ranged from 0.02-0.41 per day. In each experiment, the rate was less on wheats with higher levels of APR while in 1984 the rate on all cultivars decreased from the pre-booting to the post-booting stage of crop growth. After booting, the apparent rates of infection on susceptible and moderately susceptible cultivars were postively correlated with the mean temperature during the period over which the rate was calculated, for the range 12.9-16.2�C. Over this range, the apparent rate of infection of susceptible wheats increased at 0.095 per day per �C while that of moderately susceptible wheats increased at 0.045 per day per �C. From 16.2-203�C the rate of susceptible wheats was negatively correlated with the mean temperature, and declined at 0.043 per day per �C. There was no significant relationship between apparent rate of infection and temperature for moderately resistant wheats after booting, or for rates before booting in 1984. Development of wheat, measured on the Zadoks scale, was linear from first appearance of the flag leaf (GS 37) to mid milk (GS 75) at both sites over the four years.



1994 ◽  
Vol 34 (6) ◽  
pp. 753 ◽  
Author(s):  
GM Lodge ◽  
MG McMillan ◽  
AJ Schipp ◽  
AS Cook

Two experiments were conducted at Tamworth, New South Wales, to assess the effects of herbicides applied post-sowing pre-emergence, and at 2 post-emergence growth stages, on Danthonia (wallaby grass) dry matter yield, plant number, and plant phytotoxicity. Phytotoxicity was scored visually on a 0-5 scale (0, no phytotoxicity; 5, 100% phytotoxicity). In the post-sowing pre-emergence study, no Danthonia plants survived on plots sprayed with metribuzin (375 g a.i./ha), chlorsulfuron (45 g a.i./ha), or simazine (750 and 1500 g a.i./ha). Phytotoxicity was also high at lower rates of metribuzin (187.5 g a.i./ha) and chlorsulfuron (22.5 g a.i./ha). Dry matter yields and plant numbers on 2,4-D amine and ester treatments were not significantly different from those of unsprayed controls. On metsulfuron-methyl (3 and 6 g a.i./ha) and triasulfuron (21.4 g a.i./ha) treatments, plant numbers were similar to the controls, but Danthonia yields were lower (P<0.05). In seedling stands, the only herbicide that reduced (P<0.05) Danthonia dry matter yield compared with the unsprayed control plots was metsulfuron-methyl applied at 6, 12, and 18 g a.i./ha at the 2-4 tiller stage, and at 12 and 18 g a.i./ha at early stem elongation. At both times of application, Danthonia plant numbers were lowest (P<0.05) on the metsulfuron-methyl 12 and 18 g a.i./ha treatments. Phytotoxicity scores were >2 and highest (P<0.05) on all metsulfuron-methyl plots. These studies indicated that a range of chemicals could be used to control broadleaf weed seedlings, without damaging Danthonia seedlings.



1992 ◽  
Vol 40 (1) ◽  
pp. 13 ◽  
Author(s):  
DJ Barrett ◽  
JE Ash

Rainforest, ecotone and eucalypt forest species were grown for 22 weeks in glasshouse conditions under light, water and nutrient treatments. Plant biomass, leaf area and leaf biomass per plant increased in Eucalyptus sieberi, Eucalyptus fastigata, Pittosporum undulatum, Callicoma serratifolia, Elaeocarpus reticulatus, Backhousia myrtifolia and Ceratopetalum apetalum at high irradiance (1230-1670 μ-mol PAR m-2 s-1). Both E. sieberi and E. fastigata inhabit the relatively high light environments of northern aspects, upper southern aspects and ridge tops in the gully systems of south coastal New South Wales. Callicoma serratifolia, P. undulatum and E reticulatus are pioneer species of the ecotone around rainforest patches, and B. myrtifolia and C. apetalum are rainforest canopy species. Mean plant biomass under high irradiance was ranked: eucalypt species > ecotone species and B. myrtifolia > C. apetalum. At low irradiance (200-530 μ-mol PAR m-2 s-1) the trend observed was reversed where rainforest canopy and ecotone species produced greater plant biomass. Plant response to different water and nutrient treatments under glasshouse conditions showed that, while the light environment primarily governed plant response, interaction between treatments occurred which resulted in maximum plant biomass at relatively high levels of soil moisture and nutrients. Carbon partitioning was used as an indication of relative response to light treatments. The proportion of plant mass partitioned to leaves did not change between experimental treatments. The magnitude of the response of leaf area ratio and specific leaf weight to light treatment, however, was ranked: eucalypt species > ecotone species > rainforest canopy species. This suggested that species naturally growing outside the rainforest canopy maximised leaf area in proportion to plant mass for a given irradiance, presumably to maintain high growth rates.



1989 ◽  
Vol 29 (3) ◽  
pp. 383 ◽  
Author(s):  
PL Milthorpe ◽  
RL Dunstone

Jojoba (Simmondsia chinensis [Link] Schneider) was tested at several sites and on various soil types to assess its production potential under rainfed conditions in semi-arid areas of New South Wales. Stands were established using either plants grown from seed or cuttings taken from selected plants. With good nutrition and weed control, plant height increased at a similar rate over the experiment at all but the most sandy site, where growth was consistently poorer despite similar climatic conditions and management. Stands established from seed had extremely variable yields. Some plants failed to produce seed after 8 years while other plants consistently produced fruit after year 4, with yields as high as 1 kg clean seed per bush by year 8. The average yield was well under 200 g plant-1 except at Trangie in 1986-87 (590 g plant-1). At year 3, 50-100% of female plants were unproductive and by year 8, between 8 and 26% of plants remained unproductive. The variation in yield of the sampled population was consistently high irrespective of seasonal conditions, and usually the upper quartile yield was only marginally higher than the mean. However, the maximum yielding plant produced up to 10 times the mean yield. By contrast, the variation in yield of individuals within a clone was low regardless of the yield potential of that clone and the maximum yielding plant rarely exceeded twice the mean yield. Some clones (A, B and F) show promise as agricultural lines as they are relatively consistent yielders and show early yield development. The highest yield obtained extrapolates to 1.1 t ha-1 at year 7 at a site which averages 417 mm rainfall per year. Further research is needed to identify the reasons for the high variability and fluctuations in yield.



2002 ◽  
Vol 53 (10) ◽  
pp. 1173 ◽  
Author(s):  
M. H. Ryan ◽  
R. M. Norton ◽  
J. A. Kirkegaard ◽  
K. M. McCormick ◽  
S. E. Knights ◽  
...  

Most crops host arbuscular mycorrhizal fungi (AMF). Canola and other brassicas are some of the few exceptions. This study examined AM fungal colonisation, uptake of phosphorus (P) and zinc (Zn), growth, and yield of wheat following brassicas and crops that host AMF in 5 crop-sequence experiments in southern New South Wales and Victoria. All experiments were on alkaline Vertosols, similar to soils in the northern wheatbelt on which low AM fungal colonisation of wheat following canola, or long-fallow, has been reported to induce poor crop growth. Soils with a broad range of extractable P concentrations were chosen. AM fungal colonisation of wheat was generally lower following brassicas than hosts of AMF, although this varied with year and location. The effect on wheat AM fungal colonisation levels did not vary between brassicas with differing levels and types of root glucosinolates. Low AM fungal colonisation did not affect early wheat growth, pre-anthesis P and Zn uptake, or yield. A positive relationship between AM fungal colonisation and grain Zn and P concentrations occurred in one experiment. High levels of colonisation by AMF did not protect crop roots from damage by root pathogens and high levels of pathogen damage made interpretation of results difficult in some instances. As these findings are consistent with results from an experiment on an acidic Kandosol in southern New South Wales, it appears farmers do not need to consider the degree to which wheat will be colonised by AMF when planning crop sequences in south-eastern Australia.



2009 ◽  
Vol 49 (10) ◽  
pp. 769 ◽  
Author(s):  
K. G. McMullen ◽  
J. M. Virgona

In southern New South Wales, Australia, grazing wheat during the vegetative and early reproductive growth stages (typically during winter) can provide a valuable contribution of high quality feed during a period of low pasture growth. This paper reports results from a series of experiments investigating the agronomic management of grazed wheats in southern NSW. The effect of sowing date and grazing on dry matter production and subsequent grain yield of a range of wheat cultivars was measured in five experiments in 2004 and 2005. In all experiments, results were compared with ungrazed spring wheat (cv. Diamondbird). Grain yield of the best winter cultivar was either the same or significantly greater than the spring cultivar in each of the five experiments. Within the winter wheat cultivars, there was significant variation in grain yield, protein content and screenings, depending on site and year with the cultivar Marombi out-yielding all others. Interestingly, this cultivar usually had the least dry matter post-grazing but the greatest dry matter by anthesis of the winter wheats. Generally, if sowing of the winter wheat was delayed, then the effects on yield were small or non-existent. The results are discussed with respect to the benefits of incorporating grazing cereals into cropping programs in the medium rainfall zone of southern Australia.



1980 ◽  
Vol 20 (106) ◽  
pp. 602
Author(s):  
PGE Searle ◽  
A Thirathon ◽  
MJT Norman

The effect of time of sowing on the growth and yield of mungbean varieties (Vigna radiata var. aureus) was examined during summer in a warm humid coastal climate at Camden, New South Wales (latitude 34�s). Four varieties, Pusa Baisakhi, Berken, S8, and M4 were grown in a split-plot randomized complete block experiment with six replicates. Main plot treatments were three times of sowing (October 28, December 8 and January 19); varieties were on sub-plots. Berken, a current commercial cultivar, attained the highest grain yield, at the October sowing, of 1.5 t ha-1 in 97 days from sowing. S8 attained a yield of 1.4 t ha-1 at the October sowing in 103 days, but was susceptible to lodging, disease and pest attack. Pusa reached its highest grain yield (1.1 t ha-1) at the December sowing in 91 days. Although the grain yield of M4 was the lowest, its top dry matter yield of 5.1 t ha-1 at the December sowing indicates its promise as a forage crop.



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