Weed interference reduces yield of coppiced tea tree (Melaleuca alternifolia)

2000 ◽  
Vol 40 (8) ◽  
pp. 1157
Author(s):  
J. G. Virtue ◽  
B. G. Sutton ◽  
G. J. Murtagh ◽  
R. D. Cousens
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Biomass Yield ◽  
Leaf Biomass ◽  
Yield Losses ◽  
Melaleuca Alternifolia ◽  
Tea Tree ◽  
Weed Interference ◽  
Leaf Oil ◽  
Oil Concentration

The effects of weeds on the oil yield of tea tree, Melaleuca alternifolia (Maiden and Betche) Cheel, were examined in 6 field experiments. Tea tree is grown in plantations as a coppice crop, being annually harvested for its leaf oil. Plots were maintained with and without weed control between successive harvests. Weed interference significantly reduced leaf biomass yield of regrowth tea tree in 5 of 6 experiments, with a mean yield loss of 25%. Yield losses ranged from 9 to 47%, and these were correlated with weed biomass remaining at harvest. Weed interference did not significantly affect leaf oil concentration, or its chemical composition.

Influence of Cotton (Gossypium hirsutum) and Soybean (Glycine max) Planting Date on Weed Interference

Weed Science ◽  
1994 ◽  
Vol 42 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Tracy E. Klingaman ◽  
Lawrence R. Oliver
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Planting Date ◽  
Cotton Yield ◽  
Yield Losses ◽  
Seed Cotton ◽  
Weed Species ◽  
Planting Dates ◽  
Seed Cotton Yield ◽  
Weed Interference

Separate field experiments were conducted for cotton and soybean in 1990 and 1991 to determine the influence of planting date on yield loss due to interspecific interference from entireleaf morningglory and sicklepod and to determine the relative competitiveness of each weed species. Percent soybean yield loss due to weed interference increased as planting date was delayed from early May to early June. Averaged over weed species, yield losses from 1.7 weeds m−1row were 10, 18, and 20% for soybeans planted in early May, mid-May, and early June, respectively. Yield loss from 6.7 weeds m−1row were 17, 31, and 35% at the early May, mid-May, and early June planting dates, respectively. Percent seed cotton yield losses averaged over weed species in 1990 were 33 and 28% for the early May and early June planting dates, respectively, at 1.7 weeds m−1and 50% for both planting dates at weed densities of 6.7 plants m−1. The only experimental factor that significantly affected seed cotton yield in 1991 was weed density. Unlike soybeans, planting date had little effect on weed interference in cotton. Entireleaf morningglory was more competitive than sicklepod in both crops. Results suggest that selection of optimum soy bean planting dates may be a viable means of reducing losses due to weed interference.

scholarly journals The impact of cultivar resistance and fungicide treatment on mycotoxin content in grain and yield losses caused by Fusarium head blight in wheat

2010 ◽  
Vol 46 (No. 1) ◽  
pp. 21-26 ◽  
Author(s):  
V. Šíp ◽  
J. Chrpová ◽  
O. Veškrna ◽  
L. Bobková
Keyword(s):  
Grain Yield ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Yield Loss ◽  
Joint Effect ◽  
Yield Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Fungicide Treatment ◽  
The Impact

Reactions to artificial infection with Fusarium graminearum isolates and a new fungicide Swing Top were studied in nine winter wheat cultivars evaluated in field experiments at two sites for three years for expression of symptoms, deoxynivalenol (DON) content in grain and grain yield. The results demonstrate a pronounced and relatively stable effect of cultivar resistance on reducing head blight, grain yield losses and contamination of grain by the mycotoxin DON. It is advantageous that the moderate level of resistance to Fusarium head blight (FHB) was detected also in two commonly grown Czech cultivars Sakura and Simila. Average fungicide efficacy for DON was 49.5% and 63.9% for a reduction in yield loss, however, it was found highly variable in different years and sites. The joint effect of cultivar resistance and fungicide treatment was 86.5% for DON and even 95.4% for reducing the yield loss. A very high risk was documented for susceptible cultivars and also the effects of medium responsive cultivars were found to be highly variable in different environments and therefore not guaranteeing sufficient protection against FHB under different conditions.

scholarly journals Modeling the Competitive Effect of Euphorbia dracunculoides and Astragalus sp. in Zero Input Rainfed Chickpea

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.M. IKRAM ◽  
A. TANVEER ◽  
R. MAQBOOL ◽  
M.A. NADEEN
Keyword(s):  
Protein Content ◽  
Critical Period ◽  
Field Experiments ◽  
Seed Protein ◽  
Yield Loss ◽  
Seed Protein Content ◽  
Yield Losses ◽  
Competition Period ◽  
Crop Competition ◽  
Weed Removal

ABSTRACT: Brown chickpea (Cicer arietinum L.) is one of the two chickpea types grown in Pakistan and other countries. The critical period for weed removal in a rainfed chickpea system is an important consideration in devising weed management strategies. Field experiments were conducted in the winter season of 2011 and 2012 to determine the extent of yield loss with different periods of weed crop competition. Seven weed crop competition periods (0, 45, 60, 75, 90, 105 and 160 days after sowing - DAS) were used to identify the critical period for weed removal in rainfed chickpea. Experimental plots were naturally infested with Euphorbia dracunculoides and Astragalus sp. in both years. Individual, composite density and dry weights of E. dracunculoides and Astragalussp. increased significantly with an increase in the competition period. However, yield and yield-contributing traits of chickpea significantly decreased with an increase in the competition period. Chickpea seed yield loss was 11-53% in different weed crop competition periods. Euphorbia dracunculoides and Astragalus sp. removed 39.9 and 36.9 kg ha-1 of N, 9.61 and 7.27 kg ha-1 of P and 38.3 and 36.9 kg ha-1 of K, respectively. Season long weed competition (160 days after sowing) resulted in 19.5% seed protein content compared with 24.5% seed protein content in weed-free chickpea. A Logistic equation was fitted to yield data in response to increasing periods of weed crop competition. The critical timing of weed removal at 5 and 10% acceptable yield losses were 26 and 39 DAS, respectively. The observed critical period suggests that in rainfed chickpea, a carefully timed weed removal could prevent grain yield losses.

Month of harvest and yield components of tea tree. II. Oil concentration, composition, and yield

1996 ◽  
Vol 47 (5) ◽  
pp. 817 ◽  
Author(s):  
GJ Murtagh ◽  
GR Smith
Keyword(s):  
Biomass Yield ◽  
Significant Loss ◽  
Oil Yield ◽  
Energy Reserves ◽  
Tea Tree ◽  
Air Temperatures ◽  
Oil Concentration ◽  
Biomass Yields ◽  
The Mean ◽  
High Concentrations

Changes in the concentration, composition, and yield of oil in coppice growth of tea tree (Melaleuca alternzfolia) were assessed when plants were harvested in different months. Oil concentrations in leaves were lower when plants were harvested in July-September than in other months, but biomass yields were higher. Consequently, there was no consistent effect of harvest month on oil yield. Oil yield varied as much between the same month in different years, as between months within a year. The oil concentration in one harvest was positively related to the biomass yield at the previous harvest of the same plants, suggesting that a carryover of energy reserves contributed to oil production. The oil concentration was also positively related to the mean air temperatures over the 3 months before harvest. The proportion of the economically significant compounds in oil, terpinen-4-01 and 1,8-cineole, was not affected by either the month of harvest or regrowth cycle, but other compounds did change. There was a significant loss of monoterpene olefins from oil which was present at high concentrations.

The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

2019 ◽  
Vol 99 (4) ◽  
pp. 437-443
Author(s):  
Nader Soltani ◽  
Robert E. Nurse ◽  
Amit J. Jhala ◽  
Peter H. Sikkema
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Growth Stages ◽  
Weed Species ◽  
Weed Biomass ◽  
Weed Density ◽  
Weed Interference ◽  
Beginning Of Flowering ◽  
Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

scholarly journals The Critical Period for Weed Control (CPWC) in Potato (Solanum tuberosum L.)

2015 ◽  
Vol 43 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Dogan ISIK ◽  
Adem AKCA ◽  
Emine KAYA ALTOP ◽  
Nihat TURSUN ◽  
Husrev MENNAN
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Yield Loss ◽  
Cropping Systems ◽  
Control Period ◽  
Relative Yield ◽  
Yield Data ◽  
Weed Interference

Accurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used to assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.

Variation in oil concentration and economic return from tea-tree (Melaleuca alternifolia Cheel) oil

1990 ◽  
Vol 30 (5) ◽  
pp. 675 ◽  
Author(s):  
GJ Murtagh ◽  
RJ Etherington
Keyword(s):  
Dry Weight ◽  
Production Costs ◽  
Melaleuca Alternifolia ◽  
Tea Tree ◽  
Percentage Points ◽  
Average Production ◽  
Oil Concentration ◽  
The Mean ◽  
Set Up ◽  
Returns On Investment

The oil concentration in tea-tree (Melaleuca alternifolia Cheel) twigs was measured over 8 consecutive days during November 1987, and over 10 out of 12 consecutive days in January 1989. The oil concentration, measured in units of volume of oil per unit dry weight of twigs (v/DW), varied markedly between successive days, from 2.9-1.8% v/DW (a 38% decrease) to 1.8-3.4% v/DW (a 89% increase). The reason for such variation is unknown but it had a pronounced effect on the profitability of growing the crop. The profit, which was expressed as a return on the total set-up cost of $A17 2591ha, was estimated for each of the measured oil concentrations and fixed values of biomass yield, the price of oil and average production costs. The extreme daily variations in oil concentration mentioned above caused the return on investment to decline by 11 percentage points and increase by 16 points, respectively. When measured at the same site, the mean oil concentration increased from 3.1% vPW in November 1987 to 5.8% v/DW in January 1989. As a consequence, the respective mean returns on investment increased from 0 to 26%.

Dicamba, Chlorsulfuron, and Clopyralid as Sprayer Contaminants on Sunflower (Helianthus annuus), Mustard (Brassica juncea), and Lentil (Lens culinaris), Respectively

Weed Science ◽  
1989 ◽  
Vol 37 (4) ◽  
pp. 616-621 ◽  
Author(s):  
Douglas A. Derksen
Keyword(s):  
Helianthus Annuus ◽  
Lens Culinaris ◽  
Field Experiments ◽  
Yield Loss ◽  
Dry Weight ◽  
Yield Losses ◽  
Crop Tolerance ◽  
Crop Injury ◽  
Untreated Check ◽  
Grass Weed

Simulated sprayer tank residues of the broadleaf weed herbicides dicamba, chlorsulfuron, and clopyralid applied alone and with the grass weed herbicides sethoxydim and diclofop on sunflower, tame mustard, and lentil, respectively, caused visible crop injury and reduced dry weight and yield. Dry weight production in the greenhouse and crop tolerance ratings in the field indicated that the grass weed herbicides enhanced crop injury from dicamba, chlorsulfuron, and clopyralid. Yield reductions in field experiments were also greater when dicamba and clopyralid were mixed with grass weed herbicides and applied on sunflower and lentil, respectively. This did not occur with chlorsulfuron applied to mustard. When mixed with simulated broadleaf weed herbicide residues, diclofop enhanced dry weight reductions and crop injury and reduced yield to a greater extent than sethoxydim. Crop tolerance ratings differentiated treatments and rates but were not a good estimate of the extent of yield loss. When broadleaf weed herbicides were applied at rates simulating sprayer tank residues alone or combined with grass weed herbicides, yield losses ranged up to 40% in sunflower, 70% in mustard, and 95% in lentil, compared to the untreated check.

scholarly journals Response of Barley Genotypes to Weed Interference in Australia

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 99 ◽  
Author(s):  
Gulshan Mahajan ◽  
Lee Hickey ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Negative Correlation ◽  
Weed Management ◽  
Field Experiments ◽  
Yield Loss ◽  
Production Systems ◽  
Relative Yield ◽  
Organic Production ◽  
Integrated Weed Management ◽  
Weed Interference ◽  
Barley Genotypes

Weed-competitive genotypes could be an important tool in integrated weed management (IWM) practices. However, weed competitiveness is often not considered a priority for breeding high-yielding cultivars. Weed-competitive ability is often evaluated based on weed-suppressive ability (WSA) and weed-tolerance ability (WTA) parameters; however, there is little information on these aspects for barley genotypes in Australia. In this study, the effects of weed interference on eight barley genotypes were assessed. Two years of field experiments were performed in a split-plot design with three replications. Yield loss due to weed interference ranged from 43% to 78%. The weed yield amongst genotypes varied from 0.5 to 1.7 Mg ha−1. Relative yield loss due to weed interference was negatively correlated with WTA and WSA. A negative correlation was also found between WSA and weed seed production (r = −0.72). Similarly, a negative correlation was found between WTA and barley yield in the weedy environment (r = −0.91). The results suggest that a high tillering ability and plant height are desirable attributes for weed competitiveness in the barley genotypes. These results also demonstrated that among the eight barley genotypes, Commander exhibited superior WSA and WTA parameters and therefore, could be used in both low- and high-production systems for weed management. Westminster had a superior WSA parameter. Therefore, it could be used for weed management in organic production systems. These results also implied that genotypic ranking on the basis of WSA and WTA could be used as an important tool in strengthening IWM programs for barley.

Yield responses of oats and alfalfa to common hemp-nettle (Galeopsis tetrahit) interference

1991 ◽  
Vol 71 (1) ◽  
pp. 141-147 ◽  
Author(s):  
Anne Légère ◽  
Jean-Marc Deschênes
Keyword(s):  
Field Experiments ◽  
First Year ◽  
Weed Competition ◽  
Yield Losses ◽  
Weed Interference ◽  
Medicago Sativa L ◽  
Lower Height ◽  
Carry Over ◽  
Yield Responses ◽  
Early Harvest

Effects of various densities of hemp-nettle (Galeopsis tetrahit L.) on yields of oats (Avena sativa L.) and first year alfalfa (Medicago sativa L.) were investigated in field experiments. In both crops, emergence of hemp-nettle seedlings occurred after plot establishment such that final densities were generally greater than initial densities. Hemp-nettle plants within a stand were distributed normally over no more than seven 15-cm height classes. Very few plants were found in the lower height classes. Weight distribution according to the same height classes showed that average to tall individuals produced a large proportion of the weed biomass. Oat yields decreased as hemp-nettle density increased. In the density range of 28–248 hemp-nettle plants m−2, oat grain yield losses varied between 12 and 50%. Alfalfa was cut according to either a two-cut regime, or a three-cut regime which included an early harvest. Alfalfa yields decreased with increase in hemp-nettle density regardless of cutting regime, whereas effects of cutting regime on alfalfa yield varied with year of experiment. In each regime, timing of first harvest determined the duration of hemp-nettle interference and may have affected the degree of carry-over effects to later harvests. Key words: Hemp-nettle, Galeopsis tetrahit, weed competition, weed interference, crop losses

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