ECONOMIC LOSSES CAUSED BY WEED COMPETITION IN MANITOBA GRAIN FIELDS. I. WEED SPECIES, THEIR RELATIVE ABUNDANCE AND THEIR EFFECT ON CROP YIELDS

1960 ◽  
Vol 40 (3) ◽  
pp. 457-467 ◽  
Author(s):  
G. Friesen ◽  
L. H. Shebeski
Keyword(s):  
Relative Abundance ◽  
Crop Yields ◽  
Economic Losses ◽  
Weed Competition ◽  
Weed Species ◽  
Grain Crops ◽  
Annual Loss ◽  
Average Annual Loss ◽  
Apparent Decrease

Economic losses caused by weed competition in Manitoba grain crops were studied on 142 farm fields during a 3-year period, 1956 to 1958 inclusive. Fields were located at intervals of 6 miles along main roads and were all within a 60-mile radius of Winnipeg. Immediately after seeding, ten paired plots, each 4 feet square, were staked in each field. One member of each pair of plots was kept free of weeds by hand pulling at weekly intervals. The species of weeds present and the relative numbers were recorded. As the crops reached maturity a square-yard sample from each plot was harvested for yield determinations.Twenty-eight species of weeds were found growing in the fields. Weed counts ranged from 0 in the cleanest field to 2,143 weeds per square yard in the weediest field, with an over-all recorded average of 224 weeds per square yard. Reductions in crop yields due to weed competition in individual fields ranged from no apparent decrease to 61.5 per cent. The average reduction in crop yields for all fields over the 3-year period was 15.25 per cent. This represents an average annual loss in Manitoba of 28,657,070 bushels of grain, valued at approximately $32,379,537.

ECONOMIC LOSSES CAUSED BY WEED COMPETITION IN MANITOBA GRAIN FIELDS: II. EFFECT OF WEED COMPETITION ON THE PROTEIN CONTENT OF CEREAL CROPS

1960 ◽  
Vol 40 (4) ◽  
pp. 652-658 ◽  
Author(s):  
G. Friesen ◽  
L. H. Shebeski ◽  
A. D. Robinson
Keyword(s):  
Protein Content ◽  
Crop Yields ◽  
Growing Season ◽  
Economic Losses ◽  
Cereal Crops ◽  
Weed Competition ◽  
Available Nitrogen ◽  
Combined Analysis ◽  
Grain Crops ◽  
Weed Removal

Economic losses caused by weed competition in Manitoba grain crops were studied on 142 farm fields during a 3-year period, 1956 to 1958 inclusive. Ten paired plots were located in each farm field, one-half of each paired plot being kept weed-free throughout the growing season. Per cent protein was determined on wheat, barley and oat samples collected from 60 of these farm fields. Significant increases in protein content were obtained following weed removal in 22 of the 60 grain fields studied and small increases were noted in most other fields. In the combined analysis of all fields, removal of weeds resulted in significant increases (P =.01) in both protein content and yield of wheat, barley and oats. This suggests that weeds compete very effectively with grain crops for available nitrogen and that reductions in crop yields resulting from weed competition are generally accompanied by reductions in protein content as well.

The Concept and Application of Early Economic Period Threshold: The Case of DCPA in Onions (Allium Cepa)

Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 634-639 ◽  
Author(s):  
Claudio M. Dunan ◽  
Philip Westra ◽  
Edward E. Schweizer ◽  
Donald W. Lybecker ◽  
Frank D. Moore
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Crop Yields ◽  
Economic Feasibility ◽  
Control Measures ◽  
Economic Losses ◽  
Weed Competition ◽  
Critical Periods ◽  
Control Efficacy ◽  
The Impact

The question of when to control weeds traditionally has been approached with the calculation of critical periods (CP) based on crop yields. The concept of economic critical period (ECP) and early (EEPT) and late (LEFT) economic period thresholds are presented as a comprehensive approach to answer the same question based on economic losses and costs of control. ECP is defined as the period when the benefit of controlling weeds is greater than its cost. EEPT and LEFT are the limits of the ECP and can be used to determine when first and last weed control measures should be performed. Calculation of EEPT accounts for the economic losses due to weed competition that occur between planting and postemergence weed control. In this way it is possible to better evaluate the economic feasibility of using preplant or preemergence control tactics. The EEPT for DCPA application is analyzed in the context of onion production in Colorado. The EEPT for DCPA application was calculated from an empirical regression model that assessed the impact of weed load and time of weed removal on onion yields. The EEPT was affected by control efficacy, weed-free yield, DCPA cost, and onion price. DCPA application was economically advisable in only one of 20 fields analyzed because of the tow DCPA efficacy (60%).

EFFECT OF WEED COMPETITION AND WEED CONTROL PROGRAMS ON RUTABAGA YIELD

1980 ◽  
Vol 60 (3) ◽  
pp. 917-922 ◽  
Author(s):  
J. A. IVANY
Keyword(s):  
Weed Control ◽  
Crop Yields ◽  
Test Area ◽  
Weed Competition ◽  
Weed Species ◽  
Control Programs ◽  
Herbicide Treatments ◽  
Hand Weeding ◽  
Better Than ◽  
Weed Removal

The effects of different periods of weed competition and of trifluralin (α,α,α-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine), niclofen (2,4-dichloro-phenyl-p-nitrophenyl ether), and cultivations were studied for effects on yield of rutabaga (Brassica napobrassica Mill. ’York’). Delaying weed removal for 4 wk after crop emergence significantly reduced yields of marketable and total roots compared with plots kept weed-free all season. Delayed weeding beyond 4 wk resulted in progressively greater reductions in yield. Rutabagas kept weed-free for 2, 4, 6, and 8 wk from crop emergence by once-weekly weeding gave yields comparable to those kept weed-free all season. Herbicide treatments without hand-weeding gave significantly lower yields than those with one hand-weeding. The use of three hand-weedings with herbicides was not significantly better than herbicides with one hand-weeding. Level of weed control was dependent on weed species present in the test area; however, a combination of trifluralin and niclofen gave a broader spectrum of control and better crop yields than either used alone.

Fertiliser evenness - losses and costs: A study on the economic benefits of uniform applications of fertiliser

1999 ◽  
pp. 215-220 ◽  
Author(s):  
R. Horrell ◽  
A.K. Metherell ◽  
S. Ford ◽  
C. Doscher
Keyword(s):  
Crop Yields ◽  
Cumulative Effect ◽  
Economic Loss ◽  
Economic Benefits ◽  
Significant Loss ◽  
Economic Losses ◽  
Financial Return ◽  
Spread Pattern ◽  
Fertiliser Application ◽  
Seed Crops

Over two million tonnes of fertiliser are applied to New Zealand pastures and crops annually and there is an increasing desire by farmers to ensure that the best possible economic return is gained from this investment. Spreading distribution measurements undertaken by Lincoln Ventures Ltd (LVL) have identified large variations in the evenness of fertiliser application by spreading machines which could lead to a failure to achieve optimum potential in some crop yields and to significant associated economic losses. To quantify these losses, a study was undertaken to calculate the effect of uneven fertiliser application on crop yield. From LVL's spreader database, spread patterns from many machines were categorised by spread pattern type and by coefficient of variation (CV). These patterns were then used to calculate yield losses when they were combined with the response data from five representative cropping and pastoral situations. Nitrogen fertiliser on ryegrass seed crops shows significant production losses at a spread pattern CV between 30% and 40%. For P and S on pasture, the cumulative effect of uneven spreading accrues, until there is significant economic loss occurring by year 3 for both the Waikato dairy and Southland sheep and beef systems at CV values between 30% and 40%. For nitrogen on pasture, significant loss in a dairy system occurs at a CV of approximately 40% whereas for a sheep and beef system it is at a CV of 50%, where the financial return from nitrogen application has been calculated at the average gross revenue of the farming system. The conclusion of this study is that the current Spreadmark standards are a satisfactory basis for defining the evenness requirements of fertiliser applications in most circumstances. On the basis of Spreadmark testing to date, more than 50% of the national commercial spreading fleet fails to meet the standard for nitrogenous fertilisers and 40% fails to meet the standard for phosphatic fertilisers.Keywords: aerial spreading, crop response, economic loss, fertiliser, ground spreading, striping, uneven application, uneven spreading, yield loss

scholarly journals Low Light/Darkness as Stressors of Multifactor-Induced Senescence in Rice Plants

2021 ◽  
Vol 22 (8) ◽  
pp. 3936
Author(s):  
Ahmed G. Gad ◽  
Habiba ◽  
Xiangzi Zheng ◽  
Ying Miao
Keyword(s):  
Leaf Senescence ◽  
Crop Yields ◽  
Crop Improvement ◽  
Light Response ◽  
Development Stage ◽  
Regulatory Mechanisms ◽  
Economic Losses ◽  
Low Light ◽  
Chlorophyll Breakdown ◽  
Premature Leaf Senescence

Leaf senescence, as an integral part of the final development stage for plants, primarily remobilizes nutrients from the sources to the sinks in response to different stressors. The premature senescence of leaves is a critical challenge that causes significant economic losses in terms of crop yields. Although low light causes losses of up to 50% and affects rice yield and quality, its regulatory mechanisms remain poorly elucidated. Darkness-mediated premature leaf senescence is a well-studied stressor. It initiates the expression of senescence-associated genes (SAGs), which have been implicated in chlorophyll breakdown and degradation. The molecular and biochemical regulatory mechanisms of premature leaf senescence show significant levels of redundant biomass in complex pathways. Thus, clarifying the regulatory mechanisms of low-light/dark-induced senescence may be conducive to developing strategies for rice crop improvement. This review describes the recent molecular regulatory mechanisms associated with low-light response and dark-induced senescence (DIS), and their effects on plastid signaling and photosynthesis-mediated processes, chloroplast and protein degradation, as well as hormonal and transcriptional regulation in rice.

scholarly journals PR-1-Like Protein as a Potential Target for the Identification of Fusarium oxysporum: An In Silico Approach

BioTech ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 8
Author(s):  
Olalekan Olanrewaju Bakare ◽  
Arun Gokul ◽  
Marshall Keyster
Keyword(s):  
Antimicrobial Peptides ◽  
Fusarium Oxysporum ◽  
In Silico ◽  
Crop Yields ◽  
Research Work ◽  
Receptor Protein ◽  
Economic Losses ◽  
Protein Receptor ◽  
Novel Biomarkers ◽  
Docking Interaction

Fusarium oxysporum remains one of the leading causes of economic losses and poor crop yields; its detection is strained due to its presentation in various morphological and physiological forms. This research work sought to identify novel biomarkers for the detection of Fusarium oxysporum using in silico approaches. Experimentally validated anti-Fusarium oxysporum antimicrobial peptides (AMPs) were used to construct a profile against Fusarium oxysporum. The performance and physicochemical parameters of these peptides were predicted. The gene for the Fusarium oxysporum receptor protein PR-1-like Protein, Fpr1, was identified and translated. The resulting protein model from the translation was then validated. The anti-Fusarium oxysporum AMPs and Fusarium oxysporum receptor protein 3-D structures were characterized, and their docking interaction analyses were carried out. The HMMER in silico tool identified novel anti-Fusarium oxysporum antimicrobial peptides with good performance in terms of accuracy, sensitivity, and specificity. These AMPs also displayed good physicochemical properties and bound with greater affinity to Fusarium oxysporum protein receptor PR-1-like Protein. The tendency of these AMPs to precisely detect Fusarium oxysporum PR-1-like Protein, Fpr1, would justify their use for the identification of the fungus. This study would enhance and facilitate the identification of Fusarium oxysporum to reduce problems associated with poor crop yield, economic losses, and decreased nutritional values of plants to keep up with the growing population.

scholarly journals Extension Plant Pathology: Strengthening Resources to Continue Serving the Public Interest

2012 ◽  
Vol 102 (7) ◽  
pp. 652-655 ◽  
Author(s):  
K. L. Everts ◽  
L. Osborne ◽  
A. J. Gevens ◽  
S. J. Vasquez ◽  
B. K. Gugino ◽  
...  
Keyword(s):  
Plant Pathology ◽  
Plant Disease ◽  
Crop Yields ◽  
Economic Value ◽  
The United States ◽  
Emerging Diseases ◽  
Plant Diseases ◽  
Economic Losses ◽  
Global Competitiveness ◽  
Horticultural Crops

Extension plant pathologists deliver science-based information that protects the economic value of agricultural and horticultural crops in the United States by educating growers and the general public about plant diseases. Extension plant pathologists diagnose plant diseases and disorders, provide advice, and conduct applied research on local and regional plant disease problems. During the last century, extension plant pathology programs have adjusted to demographic shifts in the U.S. population and to changes in program funding. Extension programs are now more collaborative and more specialized in response to a highly educated clientele. Changes in federal and state budgets and policies have also reduced funding and shifted the source of funding of extension plant pathologists from formula funds towards specialized competitive grants. These competitive grants often favor national over local and regional plant disease issues and typically require a long lead time to secure funding. These changes coupled with a reduction in personnel pose a threat to extension plant pathology programs. Increasing demand for high-quality, unbiased information and the continued reduction in local, state, and federal funds is unsustainable and, if not abated, will lead to a delay in response to emerging diseases, reduce crop yields, increase economic losses, and place U.S. agriculture at a global competitive disadvantage. In this letter, we outline four recommendations to strengthen the role and resources of extension plant pathologists as they guide our nation's food, feed, fuel, fiber, and ornamental producers into an era of increasing technological complexity and global competitiveness.

Mechanical scarification technique breaks seed coat-mediated dormancy in wild oat (Avena fatua)

2021 ◽  
pp. 1-25
Author(s):  
Roberto Lujan Rocha ◽  
Yaseen Khalil ◽  
Aniruddha Maity ◽  
Hugh J. Beckie ◽  
Michael B. Ashworth
Keyword(s):  
Growth Rate ◽  
Seed Coat ◽  
Research Effort ◽  
Economic Losses ◽  
Wild Oat ◽  
Weed Species ◽  
Physical Dormancy ◽  
No Donor ◽  
Seedling Growth Rate ◽  
Oat Seeds

Abstract Wild oat is a herbicide resistance-prone global weed species that causes significant economic losses in dryland and horticultural agriculture. As a result, there has been a significant research effort in controlling this species. A major impediment to this research is the seed coat-mediated dormancy of wild oat, requiring a labor-intensive incision or puncturing of the seed coat to initiate seed germination. This study defines the most efficient settings of a mechanical thresher to overcome wild oat seed dormancy and then validates these settings using multiple populations collected from the Western Australian grain belt. We also compare the effects of rapid mechanical scarification and known germination stimulus tactics such as scarification with sulfuric acid (H2SO4), partial endosperm removal, sandpaper scarification of the seed coat, and immersion in sodium nitroprusside (NO donor SNP) solution on wild oat seedling growth rate. Threshing treatment of 1,500 rpm for 5 s provides equivalent germination compared with manually puncturing individual wild oat seeds, with no difference in seedling relative growth rate. The mechanical scarification of seeds using the thresher resulted in greater germination (66%) than H2SO4 scarification (0%), partial endosperm removal (10%), sandpaper seed coat scarification (25%), and exposure to NO donor SNP (34%). This study demonstrates that the physical dormancy of wild oat can be rapidly overcome using a commercially available mechanical thresher.

scholarly journals Weed Interference Affects Dry Bean Yield and Growth

2012 ◽  
Vol 4 (3) ◽  
pp. 70-75 ◽  
Author(s):  
Hossein GHAMARI ◽  
Goudarz AHMADVAND
Keyword(s):  
Chenopodium Album ◽  
Growing Season ◽  
Amaranthus Retroflexus ◽  
Growth And Yield ◽  
Weed Competition ◽  
Weed Species ◽  
Dry Bean ◽  
Logistic Equations ◽  
Weed Interference ◽  
Minimum Number

Dry bean is one of the most important pulse crops in Iran. Field study was conducted in 2011 to evaluate effects of weed competition from a natural flora on growth and yield of dry bean (Phaseolus vulgaris L.). The treatments consisted of weed infestation and weed removal periods (10, 20, 30, 40 and 50 days) after crop emergence. Control plots kept weed-infested and weed-free throughout growing season. To assess the weed competition effect on crop characteristics, Richards, Gompertz and logistic equations were fitted to the data. The most abundant weed species were Chenopodium album and Amaranthus retroflexus. Increase in duration of weed interference decreased the stem height of dry bean. At the end of the growing season, dry bean was 20 cm taller in season-long weed-free treatment compared to the season-long weed-infested treatment. As the number of days of weed interference increased, a declining trend of LAI and number of pods was observed. The minimum number of pods was obtained in season-long weed-infested treatment (5.01 pods/plant). Weed interference during the whole growing season, caused a 60% reduction in yield. Considering 5% and 10% acceptable yield lost, the critical period of weed competition was determined from 20 to 68 and 23 to 55 days after planting (DAE), respectively.

scholarly journals Effect of duration of weed competition and weed control on the yield of Indian spinach

1970 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
MSA Khan ◽  
MA Hossain ◽  
M Nurul Islam ◽  
SN Mahfuza ◽  
MK Uddin
Keyword(s):  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Agricultural Research ◽  
Cyperus Rotundus ◽  
Weed Competition ◽  
Weed Species ◽  
Maximum Benefit ◽  
Hand Weeding ◽  
Crop Weed Competition

Field experiments were conducted at the research farm of Bangladesh Agricultural Research Institute, Joydebpur during kharif-1 (March to July) seasons of 2005 and 2006 to identify the critical period of crop-weed competition for Indian spinach. Major weed species were Paspalurn commersoni, Echinochlaa crusgalli. Lie nv/nc india. Cyanotis axillaris and Cyperus rotundus. The lowest weed dry matter was 76.3 g m-2 in 2005 and l01.60 g m-2 in 2006 from the plots weeded up to 40 days after transplanting (DAT). The highest yields were obtained (74.82 t ha in 2005 and 48.48 t ha in 2006) from the weed free plots. The fresh yield of Indian spinach did not vary among no weeding upto 20, 30 and 40 DAT in 2006. But weeded plot upto 30 and 40 DAT produced identical yield in 2005. Maximum BCR (4.52) was obtained from weeded plots upto 30 DAT in 2005 but BCR (2.60) was same from weeded upto 30 and 40 DA F in 2006. On an average, highest BCR (3.55) was recorded from weeding upto 30 DAT. Results revealed that the critical period of crop weed competition lies between 20 and 30 DAT and two times hand weeding would be necessary within 30 DAT for maximum benefit. Key Words: Crop-weed competitions, critical period, weed management and Indian spinach. doi: 10.3329/bjar.v33i4.2306 Bangladesh J. Agril. Res. 33(4) : 623-629, December 2008

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