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.

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.

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.

scholarly journals THE INFLUENCE OF A COMMERCIAL FERTILIZER TREATMENT ON WEED COMPETITION IN SPRING SOWN WHEAT

1961 ◽  
Vol 41 (2) ◽  
pp. 231-238 ◽  
Author(s):  
W. Nakoneshny ◽  
G. Friesen
Keyword(s):  
Protein Content ◽  
Ammonium Phosphate ◽  
Phosphate Fertilizer ◽  
Weed Competition ◽  
Fertilizer Treatment ◽  
Combined Effects ◽  
Commercial Fertilizer ◽  
High Level ◽  
Weed Removal

Applications of ammonium phosphate fertilizer (11-48-0) at 40 pounds per acre on six farm fields in Manitoba were effective in reducing losses in wheat yields caused by weed competition. Average losses in yield due to weed competition were 20.5 per cent in unfertilized portions of the fields and only 11.7 per cent in fertilized portions of the same fields. Increases in wheat yields resulting from fertilizer treatment were approximately equal to increases resulting from weed removal. However, higher yields resulting from fertilizer treatment were sometimes accompanied by decreases in the protein content of the harvested crop. Increased yields resulting from weed removal were generally accompanied by significant increases in the protein content. The combined effects of fertilizer treatment and of weed removal produced the largest increases in yield of wheat and maintained the protein content at a comparatively high level.

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 Combined simulation and optimization framework for irrigation scheduling in agriculture fields

2021 ◽  
Author(s):  
Mireia Fontanet ◽  
Daniel Fernàndez-Garcia ◽  
Gema Rodrigo ◽  
Francesc Ferrer ◽  
Josep Maria Villar
Keyword(s):  
Crop Yields ◽  
Root Zone ◽  
Growing Season ◽  
Irrigation Scheduling ◽  
Irrigated Agriculture ◽  
Traditional Methods ◽  
Simulation And Optimization ◽  
Optimization Framework ◽  
Net Margin ◽  
Combined Simulation

AbstractIn the context of growing evidence of climate change and the fact that agriculture uses about 70% of all the water available for irrigation in semi-arid areas, there is an increasing probability of water scarcity scenarios. Water irrigation optimization is, therefore, one of the main goals of researchers and stakeholders involved in irrigated agriculture. Irrigation scheduling is often conducted based on simple water requirement calculations without accounting for the strong link between water movement in the root zone, soil–water–crop productivity and irrigation expenses. In this work, we present a combined simulation and optimization framework aimed at estimating irrigation parameters that maximize the crop net margin. The simulation component couples the movement of water in a variably saturated porous media driven by irrigation with crop water uptake and crop yields. The optimization component assures maximum gain with minimum cost of crop production during a growing season. An application of the method demonstrates that an optimal solution exists and substantially differs from traditional methods. In contrast to traditional methods, results show that the optimal irrigation scheduling solution prevents water logging and provides a more constant value of water content during the entire growing season within the root zone. As a result, in this case, the crop net margin cost exhibits a substantial increase with respect to the traditional method. The optimal irrigation scheduling solution is also shown to strongly depend on the particular soil hydraulic properties of the given field site.

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.

Critical time for weed removal in glyphosate-resistant soybean as influenced by preemergence herbicides

2019 ◽  
Vol 33 (03) ◽  
pp. 393-399 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Pavle Pavlovic ◽  
O. Adewale Osipitan ◽  
Ethann R. Barnes ◽  
Clint Beiermann ◽  
...  
Keyword(s):  
Field Experiments ◽  
Critical Time ◽  
Growing Season ◽  
Control Programs ◽  
Main Plot ◽  
Repeated Use ◽  
Sites Of Action ◽  
Alternative Sites ◽  
Preemergence Herbicides ◽  
Weed Removal

AbstractWidespread and repeated use of glyphosate resulted in an increase in glyphosate-resistant (GR) weeds. This led to an urgent need for diversification of weed control programs and use of PRE herbicides with alternative sites of action. Field experiments were conducted over a 4-yr period (2015 to 2018) across three locations in Nebraska to evaluate the effects of PRE-applied herbicides on critical time for weed removal (CTWR) in GR soybean. The studies were laid out in a split-plot arrangement with herbicide regime as the main plot and weed removal timing as the subplot. The herbicide regimes used were either no PRE or premix of either sulfentrazone plus imazethapyr (350 + 70 g ai ha−1) or saflufenacil plus imazethapyr plus pyroxasulfone (26 + 70 + 120 g ai ha−1). The weed removal timings were at V1, V3, V6, R2, and R5 soybean stages, with weed-free and weedy season-long checks. Weeds were removed by application of glyphosate (1,400 g ae ha−1) or by hoeing. The results across all years and locations suggested that the use of PRE herbicides delayed CTWR in soybean. In particular, the CTWR without PRE herbicides was determined to be around the V1 to V2 (14 to 21 d after emergence [DAE]) growth stage, depending on the location and weed pressure. The use of PRE-applied herbicides delayed CTWR from about the V4 (28 DAE) stage up to the R5 (66 DAE) stage. These results suggest that the use of PRE herbicides in GR soybean could delay the need for POST application of glyphosate by 2 to 5 wk, thereby reducing the need for multiple applications of glyphosate during the growing season. Additionally, the use of PRE herbicides could provide additional modes of action needed to manage GR weeds in GR soybean.

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.

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