scholarly journals Humic substances and its distribution in coffee crop under cover crops and weed control methods

2016 ◽  
Vol 73 (4) ◽  
pp. 371-378 ◽  
Author(s):  
Bruno Henrique Martins ◽  
Cezar Francisco Araujo-Junior ◽  
Mario Miyazawa ◽  
Karen Mayara Vieira
2017 ◽  
Vol 2 (2) ◽  
pp. 68
Author(s):  
Bruno Henrique Martins ◽  
Cezar Francisco Araujo Junior ◽  
Mario Miyazawa ◽  
Karen Mayara Vieira ◽  
Carlos Alberto Hamanaka ◽  
...  

Weed control methods in coffee crops can significantly influence carbon (C) stocks of soil humic substances. The aim of this study was to evaluate C stocks in an experimental coffee crop submitted to conservation agriculture for weed control between coffee rows. The study was carried out in a very clayey Dystroferric Red Latosol, Londrina, Paraná state (23°21’30” S; 51°10’17” W), cultivated with cultivar Mundo Novo IAC 379-19. In 2008, the experiment was established as randomized block design with four replicates within split-split plot scheme. Seven weed control methods between coffee rows were considered (hand weeding; portable mechanical mower; herbicides application; two cover crops; weed check and spontaneous). In September 2013, coffee shrub pruning was conducted and residues were distributed along inter rows. The weed control methods were considered as the main-plot factor and sampling period (March 2014 and February 2015) as the split-plot. Soil samples were collected at the center of the inter rows at four depth increments. C stocks evaluation included total organic carbon determination by chromic acid wet oxidation. Humic substances were characterized by UV-Vis spectroscopy. Most of the considered weed control methods did not affect organic carbon storage in 0 – 40 cm layer, nevertheless led to increase at topsoil. In 2015, the humin fraction C stock was 54 % higher at superficial layer than subsequent depth, presenting 39 % average increase at the 2014/2015 interval. Although C stocks from humic and fulvic acids did not vary, more conjugated/condensed characteristic for the fulvic fraction was observed.


2012 ◽  
Vol 65 (3) ◽  
pp. 119-126
Author(s):  
Dorota Gawęda ◽  
Cezary A. Kwiatkowski

The aim of this 3-year field study was to evaluate the effect of some stubble crops and in-crop weed control methods on the species composition, number and air-dry weight of weeds in a wheat crop grown in short-term monoculture. The study was conducted in the period 2009-2011 in the Uhrusk Experimental Farm on mixed rendzina soil classified as very good rye soil complex. It included various types of stubble crops ploughed in each year (control treatment without cover crop, white mustard, lacy phacelia, a mixture of legumes – narrow-leaf lupin + field pea) and methods of weed control in spring wheat (mechanical, mechanical and chemical, chemical weed control). On average during the study period, all stubble crops used reduced the air-dry weight of weds in the treatments with mechanical weed management relative to the control treatment. Irrespective of the weed control method, the number of weeds in the wheat crop was significantly lower only after the ploughing in of white mustard. Mechanical weed management proved to be less effective in reducing the number and dry weight of weeds compared to other weed control methods. The white mustard and legume mixture cover crops had a reducing effect on the number of weed species in relation to the treatment without cover crops. The highest floristic diversity of weed communities was found in the spring wheat crop in which only mechanical weeding alone was used.


2021 ◽  
pp. 1-28
Author(s):  
Nicholas T. Basinger ◽  
Nicholas S. Hill

Abstract With the increasing focus on herbicide-resistant weeds and the lack of introduction of new modes of action, many producers have turned to annual cover crops as a tool for reducing weed populations. Recent studies have suggested that perennial cover crops such as white clover could be used as living mulch. However, white clover is slow to establish and is susceptible to competition from winter weeds. Therefore, the objective of this study was to determine clover tolerance and weed control in established stands of white clover to several herbicides. Studies were conducted in the fall and winter of 2018 to 2019 and 2019 to 2020 at the J. Phil Campbell Research and Education Center in Watkinsville, GA, and the Southeast Georgia Research and Education Center in Midville, GA. POST applications of imazethapyr, bentazon, or flumetsulam at low and high rates, or in combination with 2,4-D and 2,4-DB, were applied when clover reached 2 to 3 trifoliate stage. Six weeks after the initial POST application, a sequential application of bentazon and flumetsulam individually, and combinations of 2,4-D, 2,4-DB, and flumetsulam were applied over designated plots. Clover biomass was similar across all treatments except where it was reduced by sequential applications of 2,4-D + 2,4-DB + flumetsulam in the 2019 to 2020 season indicating that most treatments were safe for use on establishing living mulch clover. A single application of flumetsulam at the low rate or a single application of 2,4-D + 2,4-DB provided the greatest control of all weed species while minimizing clover injury when compared to the non-treated check. These herbicide options allow for control of problematic winter weeds during clover establishment, maximizing clover biomass and limiting canopy gaps that would allow for summer weed emergence.


Author(s):  
Katja Koehler-Cole ◽  
Christopher A. Proctor ◽  
Roger W. Elmore ◽  
David A. Wedin

Abstract Replacing tillage with cover crops (CC) for weed management in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems with mechanical weed control has many soil health benefits but in the western Corn Belt, CC establishment after harvest is hampered by cold temperatures, limited labor and few compatible CC species. Spring-planted CC may be an alternative, but information is lacking on suitable CC species. Our objective was to evaluate four spring-planted CC with respect to biomass production and weed suppression, concurrent with CC growth and post-termination. Cover crop species tested were oat (Avena sativa L.), barley (Hordeum vulgare L.), brown mustard [Brassica juncea (L.) Czern.] and yellow mustard (Brassica hirta Moench). They were compared to no-CC treatments that were either tilled pre- and post-planting of soybean (no-CC tilled) or not tilled at all (no-CC weedy). CC were planted in late March to early April, terminated 52–59 days later using an undercutter, and soybean was planted within a week. The experiment had a randomized complete block design with four replications and was repeated for 3 years. Mustards and small grains produced similar amounts of biomass (1.54 Mg ha−1) but mustard biomass production was more consistent (0.85–2.72 Mg ha−1) than that of the small grains (0.35–3.81 Mg ha−1). Relative to the no-CC weedy treatment, mustards suppressed concurrent weed biomass in two out of 3 years, by 31–97%, and small grains suppressed concurrent weed biomass in only 1 year, by 98%. Six weeks after soybean planting, small grains suppressed weed biomass in one out of 3 years, by 79% relative to the no-CC weedy treatment, but mustards did not provide significant weed suppression. The no-CC tilled treatment suppressed weeds each year relative to the no-CC weedy treatment, on average 87%. The ineffective weed control by CC reduced soybean biomass by about 50% six weeks after planting. While spring-planted CC have the potential for pre-plant weed control, they do not provide adequate early season weed suppression for soybean.


2012 ◽  
Vol 27 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Steven J. Shirtliffe ◽  
Eric N. Johnson

AbstractOrganic farmers in western Canada rely on tillage to control weeds and incorporate crop residues that could plug mechanical weed-control implements. However, tillage significantly increases the risk of soil erosion. For farmers seeking to reduce or eliminate tillage, potential alternatives include mowing or using a roller crimper for terminating green manure crops (cover crops) or using a minimum tillage (min-till) rotary hoe for mechanically controlling weeds. Although many researchers have studied organic crop production in western Canada, few have studied no-till organic production practices. Two studies were recently conducted in Saskatchewan to determine the efficacy of the following alternatives to tillage: mowing and roller crimping for weed control, and min-till rotary hoeing weed control in field pea (Pisum sativum L.). The first study compared mowing and roller crimping with tillage when terminating faba bean (Vicia faba L.) and field pea green manure crops. Early termination of annual green manure crops with roller crimping or mowing resulted in less weed regrowth compared with tillage. When compared with faba bean, field pea produced greater crop biomass, suppressed weeds better and had less regrowth. Wheat yields following pea were not affected by the method of termination. Thus, this first study indicated that roller crimping and mowing are viable alternatives to tillage to terminate field pea green manure crops. The second study evaluated the tolerance and efficacy of a min-till rotary harrow in no-till field pea production. The min-till rotary hoe was able to operate in no-till cereal residues and multiple passes did not affect the level of residue cover. Field pea exhibited excellent tolerance to the min-till rotary hoe. Good weed control occurred with multiple rotary hoe passes, and pea seed yield was 87% of the yield obtained in the herbicide-treated check. Therefore, this second study demonstrated that min-till rotary hoeing effectively controls many small seeded annual weeds in the presence of crop residue and thus can reduce the need for tillage in organic-cropping systems.


2020 ◽  
Author(s):  
Saraswathi Shanmugam ◽  
Eduardo Assunção ◽  
Ricardo Mesquita ◽  
André Veiros ◽  
Pedro D. Gaspar

A weed plant can be described as a plant that is unwanted at a specific location at a given time. Farmers have fought against the weed populations for as long as land has been used for food production. In conventional agriculture this weed control contributes a considerable amount to the overall cost of the produce. Automatic weed detection is one of the viable solutions for efficient reduction or exclusion of chemicals in crop production. Research studies have been focusing and combining modern approaches and proposed techniques which automatically analyze and evaluate segmented weed images. This study discusses and compares the weed control methods and gives special attention in describing the current research in automating the weed detection and control. Keywords: Detection, Weed, Agriculture 4.0, Computational vision, Robotics


Author(s):  
Ileana BOGDAN ◽  
Teodor RUSU ◽  
Ştefania GADEA ◽  
Ilarie IVAN ◽  
Paula MORARU ◽  
...  

The paper present the results of 26 variants of weed control in maize (grouped in 6 distinctly strategies) which were tested in 2010 agricultural year in a one factorial stationary experiment. Three of the strategies were based on post emergence weed control methods, two of them – on pre-emergent weed control method and one of them – based on both methods. The main goal was establishing an optimal network weeds control in maize crop. Maize weed in Luduş area increased, due to weed seeds reserve in the arable stratum and weather conditions, which allow weeds to grow alternatively, and because of the development of problem-causing species during the maize vegetation period, when no tilling is performed.


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