Changes in dominant weeds of wheat in a rice–wheat rotation system as affected by composted manure and straw amendments

Weed Science ◽  
2021 ◽  
pp. 1-11
Author(s):  
Yunhui Duan ◽  
Haiyan Zhang ◽  
Min Han ◽  
Aimei Hong ◽  
Yong Li ◽  
...  

Abstract A study was conducted to identify whether composted manure and straw amendments (replacement of a portion of chemical fertilizer [50% of the total nitrogen application] with composted pig manure, and straw return [all straw from the previous rice crop] combined with chemical fertilizer) compared with no fertilization and chemical fertilizer only would change the dominant species of wheat-associated weeds as well as influence their growth and seed yield in a rice (Oryza sativa L.)–wheat (Triticum aestivum L.) rotation system. The study was initiated in 2010, and the treatment effects on the species, density, plant height, shoot biomass, seed yield of dominant weeds, and wheat yields were assessed in 2017 and 2018. Fertilization significantly increased the height, density, and yield of wheat, as well as the shoot biomass of wheat-associated weeds, but decreased the weed species number. A total of 17 and 14 weed species were recorded in the experimental wheat fields in 2017 and 2018, respectively. The most dominant weed species were American sloughgrass [Beckmannia syzigachne (Steud.) Fernald] and catchweed bedstraw (Galium aparine L.), which made up more than 64% of the weed community in all treatments. When the chemical fertilizer application was amended with pig manure compost and straw return, the relative abundance of B. syzigachne significantly decreased, while the relative abundance of G. aparine significantly increased. The application of the chemical fertilizer-only treatment resulted in increases in the density, shoot biomass, and seed yield of B. syzigachne, while the composted manure and straw amendments applied together with chemical fertilizer led to significant increases in the density, shoot biomass, and seed yield of G. aparine. Consequently, further research on ways to promote greater cropping system diversity will be needed to prevent the selection of weed species that are adapted to a limited suite of crop management practices.

Weed Science ◽  
2019 ◽  
Vol 67 (3) ◽  
pp. 318-326
Author(s):  
Haiyan Zhang ◽  
Yicheng Sun ◽  
Yong Li ◽  
Guojun Sun ◽  
Fang Yuan ◽  
...  

AbstractIn a rice (Oryza sativa L.)–wheat (Triticum aestivumL.) rotation system, a study was conducted to determine the effects of different fertilization regimens (no fertilization, replacement of a portion of chemical fertilizer with composted pig manure, chemical fertilizer only, and straw return combined with chemical fertilizer) on the weed communities and wheat yields after 4 and 5 yr. The impact of the long-term recurrent fertilization regimen initiated in 2010 on the composition and diversity of weed communities and the impact of the components and total amount of fertilizer on wheat yields were assessed in 2014 and 2015. Totals of 19 and 16 weed species were identified in experimental wheat fields in 2014 and 2015, respectively, but the occurrence of weed species varied according to the fertilization regimen. American sloughgrass [Beckmannia syzigachne(Steud.) Fernald], water starwort [Myosoton aquaticum(L.) Moench], and lyrate hemistepta (Hemistepta lyrataBunge.) were adapted to all fertilization treatments and were the dominant weed species in the experimental wheat fields. The greatest number of weed species were observed under the no-fertilization treatment, in which 40% of the weed community was composed of broadleaf weeds and the lowest wheat yields were obtained. With fertilizer application, the number of weed species was reduced, the height of weeds increased significantly, the density of broadleaf weeds was significantly reduced, the biodiversity indices of weed communities decreased significantly, and higher wheat yields were obtained. Only the chemical fertilizer plus composted pig manure treatment and the chemical fertilizer–only treatment increased the density of grassy weeds and the total weed community density. The treatment with chemical fertilizer only also resulted in the highest density ofB. syzigachne. Rice straw return combined with chemical fertilizer yielded the lowest total weed density, which suggests that it inhibited occurrence of weeds. The different fertilizer regimens not only affected the weed species composition, distribution, and diversity, but also the weed density. Our study provides new information from a rice–wheat rotation system on the relationship between soil amendments and agricultural weed infestation.


Weed Science ◽  
2021 ◽  
pp. 1-40
Author(s):  
Pinglei Gao ◽  
Aimei Hong ◽  
Min Han ◽  
Minghan Song ◽  
Yunhui Duan ◽  
...  

ABSTRACT As part of a long-term experiment to determine the impacts of composted manure and straw amendments (replacing 50% of chemical fertilizer with composted pig manure, wheat straw return combined with chemical fertilizer, and setting no fertilizer and chemical fertilizer-only as controls) on rice-associated weeds in a rice (Oryza sativa L.) - wheat (Triticum aestivum L.) rotation system, species richness, abundance, density, and biomass of weeds were assessed during years eight and nine. Fertilization decreased the species richness and total density of rice-associated weeds but increased their total biomass. The species richness and densities of broadleaf and sedge weeds decreased with fertilization, while species richness grass weeds increased only with straw return and density was not significantly affected. The shoot biomass per square meter of grass and broadleaf weeds were significantly higher with fertilization treatments than with the no fertilizer control, while that of sedge weeds declined with fertilizer application. With fertilization, the densities of monarch redstem (Ammannia baccifera L.) and smallflower umbrella sedge (Cyperus difformis L.) decreased, that of Chinese sprangletop [Leptochloa chinensis (L.) Nees] increased, and those of barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] and monochoria [Monochoria vaginalis (Burm. f.) C. Presl ex Kunth] were not significantly affected. Ammannia baccifera was the most abundant weed species in all treatments. Whereas composted pig manure plus fertilizer resulted in higher density of A. baccifera and lower shoot biomass per plant than chemical fertilizer only; wheat straw return plus chemical fertilizer caused lower density and shoot biomass of A. baccifera. Therefore, it may be possible that fertilization strategies that suppress specific weeds could be used as improved weed management program components in rice production systems.


2005 ◽  
Vol 45 (6) ◽  
pp. 711 ◽  
Author(s):  
L. J. Rew ◽  
R. W. Medd ◽  
R. Van de Ven ◽  
J. J. Gavin ◽  
G. R. Robinson ◽  
...  

Weed management is one of the most important economic and agronomic issues facing farmers in Australia’s grain regions. Weed species occurrence and abundance was monitored between 1997 and 2000 on 46 paddocks (sites) across 18 commercial farms located in the Northern Grain Region. The sites generally fell within 4 disjunct regions, from south to north: Liverpool Plains, Moree, Goondiwindi and Kingaroy. While high species richness was found (139 species or species groups), only 8 species occurred in all 4 regions and many (56 species) only occurred at 1 site or region. No species were observed at every site but 7 species (Sonchus spp., Avena spp., Conyza spp., Echinochloa spp., Convolvulus erubescens, Phalaris spp. and Lactuca serriola) were recorded on more than 70% of sites. The average number of species observed within crops after treatment and before harvest was less than 13. Species richness tended to be higher in winter pulse crops, cotton and in fallows, but overall was similar at the different sampling seasons (summer v. winter). Separate species assemblages associated with the Goondiwindi and Kingaroy regions were identified by correspondence analysis but these appeared to form no logical functional group. The species richness and density was generally low, demonstrating that farmers are managing weed populations effectively in both summer and winter cropping phases. Despite the apparent adoption of conservation tillage, an increase in opportunity cropping and the diversity of crops grown (13) there was no obvious effect of management practices on weed species richness or relative abundance. Avena spp. and Sonchus spp. were 2 of the most dominant weeds, particularly in central and southern latitudes of the region; Amaranthus spp. and Raphanus raphanistrum were the most abundant species in the northern part of the region. The ubiquity of these and other species shows that continued vigilance is required to suppress weeds as a management issue.


Antibiotics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1173
Author(s):  
Baocheng Dong ◽  
Wei Li ◽  
Wenyong Xu

Recycling of organic wastes in agricultural ecosystems to partially substitute chemical fertilizer is recommended to improve soil productivity and alleviate environmental degradation. However, livestock manure- and sewage sludge-derived amendments are widely known to potentially carry antibiotic residues. The aim of this study is to investigate how substituting organic fertilizer for chemical fertilizer affects soil quality and antibiotic residues in agricultural soil, as well as their tradeoffs. A field experiment was conducted with the different treatments of pig manure and sewage sludge as typical organic fertilizers at equal total nitrogen application rates. The analysis of variance showed that the increments on the levels of residual antibiotics in the agricultural soils due to organic substitution for chemical fertilizer by pig manure and sewage sludge were observed. The antibiotic residues ranged from 13.73 to 76.83 ng/g for all treatments. Partial organic substitution significantly increased the sequestration of antibiotics in agricultural soil by 138.1~332.5%. Organic substitution will also significantly improve soil quality, especially for nutrient availability. Based on principal component analysis, organic substitution will strongly affected soil quality and antibiotic contamination. Pearson’s correlation showed that soil physicochemical properties had significant correlations with concentrations of antibiotics in soil, indicating organic fertilizers can promote the persistence of antibiotics in soil by modifying soil quality. To balance the benefits and risks, appropriate management practices of organic fertilizers should be adopted.


Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 326-337 ◽  
Author(s):  
K. Neil Harker ◽  
John T. O'Donovan ◽  
R. Byron Irvine ◽  
T. Kelly Turkington ◽  
George W. Clayton

Wild oat causes more crop yield losses and accounts for more herbicide expenditures than any other weed species on the Canadian Prairies. A study was conducted from 2001 to 2005 at four Canadian Prairie locations to determine the influence of repeated cultural and herbicidal management practices on wild oat population density, biomass, and seed production, and on barley biomass and seed yield. Short or tall cultivars of barley were combined with normal or double barley seeding rates in continuous barley or a barley–canola–barley–field-pea rotation under three herbicide rate regimes. The same herbicide rate regime was applied to the same plots in all crops each year. In barley, cultivar type and seeding rate were also repeated on the same plots year after year. Optimal cultural practices (tall cultivars, double seeding rates, and crop rotation) reduced wild oat emergence, biomass, and seed production, and increased barley biomass and seed yield, especially at low herbicide rates. Wild oat seed production at the quarter herbicide rate was reduced by 91, 95, and 97% in 2001, 2003, and 2005, respectively, when tall barley cultivars at double seeding rates were rotated with canola and field pea (high management) compared to short barley cultivars at normal seeding rates continuously planted to barley (low management). Combinations of favorable cultural practices interacted synergistically to reduce wild oat emergence, biomass and seed production, and to increase barley yield. For example, at the quarter herbicide rate, wild oat biomass was reduced 2- to 3-, 6- to 7-, or 19-fold when optimal single, double, or triple treatments were combined, respectively. Barley yield reductions in the low-management scenario were somewhat compensated for by full herbicide rates. However, high management at low herbicide rates often produced more barley than low management in higher herbicide rate regimes.


1970 ◽  
Vol 9 ◽  
pp. 15-20
Author(s):  
M. D. Bhatt ◽  
S. R. Pant ◽  
S. P. Singh

Experiments were conducted in two varieties of transplanted paddy (cv. Radha-4 and Neemai) during the rainy season of 2004-2005 in the Far-Western Terai region of Nepal to assess the effect of weed management practice. Four experiments were conducted in randomized block design with three replications viz. unweeded (T0), weed free (TT), manured plus twice hand-weeded after 25 and 50 days of transplanting (T1), and chemical fertilizer plus butachlor (weedicide) application (1.5 kg ha-1) (T2). A total of 48 weed species were identified with densities of 208 ind. m-2 in Radha-4 and 196 ind. m-2 in Neemai. The mean maximum biomass of paddy in weed-free plots were 3553.6 and 3588.4 g m-2 in Radha-4 and Neemai respectively. This biomass was more or less similar to twice hand-weeded plots and herbicide treated plots being 1.3% lowering in both the varieties, compared to weed-free plots. Compared to weed-free plots, the biomass reduction in unweeded plots was recorded 26.1% lower in Radha-4 and 26.3% in Neemai. The weed biomass was recorded highest in unweeded plots (296.9 and 236.2 g m-2) and lowest 155.7 and 109.1 g m-2 in twice hand-weeded plots. The trend of grain yield in both the varieties were: weed free (TT) > manured plus twice hand-weeded after 25 and 50 days of transplanting (T1) > chemical fertilizer plus butachlor application (1.5 kg/ha) (T2) > unweeded (T0).Key words: Rice; Weeds control; Western Terai; BiomassDOI: 10.3126/njst.v9i0.3157Nepal Journal of Science and Technology 9 (2008) 15-20


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xinchun Lu ◽  
Al-Kaisi Mahdi ◽  
Xiao-zeng Han ◽  
Xu Chen ◽  
Jun Yan ◽  
...  

Abstract Application of phosphorus (P), a major plant nutrient, as fertilizer is critical to maintain P level for crop production and yield in most cultivated soils. While, it may impact the dynamics, limited studies have examined the long-term effects of fertilization on P fractions in a soil profile in Mollisol. A long-term field experiment was conducted at the State Key Experimental Station of Agroecology of the Chinese Academy of Sciences in Hailun county, Heilongjiang Province, China. A sequential fractionation procedure was used to determine the effect of fertilizer (types) treatments including no fertilizer (CK), chemical fertilizer (NPK), chemical fertilizer plus straw (NPK + S) and pig manure (OM) on fractions of P and their distribution within 0–100 cm soil profiles. Unlike CK treatment, the long-term application of fertilizers increased the concentration and accumulation of total and available P in 0–20 and 0–40 cm soil depths than deeper soils, respectively. The phosphorus activity coefficient (PAC) ranged from 1.5 to 13.8% within 0–100 cm soil depth. The largest PAC value was observed under OM treatment at 0–40 cm soil depth and under NPK + S treatment at 40–100 cm soil depth. The Ca2-P and Ca8-P concentrations increased significantly by 0.5–7.5 times and 0.5–10.4 times, respectively in OM treatment with the largest value in 0–40 cm soil depth over CK treatment. The Al-P concentration under NPK + S and OM treatments increased throughout the soil profile. The OM treatment increased all Po concentrations in the 0–40 cm soil depth, while NPK and NPK + S treatments increased labile organic P, moderately labile organic P, and highly stable organic P in the 0–20 cm soil depth. Thus, the application of fertilizer and straw, or organic manure may enhance inorganic and organic P pool in a Mollisol in Northeast China. Thus, organic manure application in the subsoil as a potential P source and their impact should be considered in developing management practices and policies regarding nutrient management.


Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 204-208 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
David E. Johnson

Rice flatsedge and barnyardgrass are widespread and competitive weeds in direct-seeded rice. Developing integrated weed management strategies that elevate suppression of weeds by rice through crop density, nutrition, and cultivar choice requires better understanding of the extent to which rice interferes with the growth of these weeds and how these species respond to resource limitation with crop interference. Rice interference reduced the height of barnyardgrass but did not affect height of rice flatsedge. These weed species were able to grow taller than rice and thus avoided being shaded. Increased specific stem length under crop interference may demonstrate a strategy of stem elongation to allow the top portion of the weeds to be kept out of shade. Rice interference reduced inflorescence and shoot biomass of both weed species. Barnyardgrass showed the ability to reduce the effects of rice interference by increasing leaf weight ratio. The present study shows that crop interference alone may reduce weed growth but may not give complete control of these weed species. This highlights the need for the integration of management practices to achieve control of these weed species.


Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 605
Author(s):  
Peder K. Schmitz ◽  
Hans J. Kandel

Planting date (PD), seeding rate (SR), relative maturity (RM) of cultivars, and row spacing (RS) are primary management factors affecting soybean (Glycine max (L.) Merr.) yield. The individual and synergistic effects of PD, SR, RM, and RS on seed yield and agronomic characteristics in North Dakota were herein investigated. Early and late PD, early and late RM cultivars, two SR (408,000 and 457,000 seed ha−1), and two RS (30.5 and 61 cm) were evaluated in four total environments in 2019 and 2020. Maximizing green canopy cover prior to the beginning of flowering improved seed yield. Individual factors of early PD and narrow RS resulted in yield increase of 311 and 266 kg ha−1, respectively. The combined factors of early PD, late RM, high SR, and narrow RS improved yield by 26% and provided a $350 ha−1 partial profit over conventional practices. Canopy cover and yield had relatively weak relationships with r2 of 0.36, 0.23, 0.14, and 0.21 at the two trifoliolate, four trifoliolate, beginning of flowering, and beginning of pod formation soybean growth stages, respectively. Producers in the most northern soybean region of the USA should combine early planting, optimum RM cultivars, 457,000 seed ha−1 SR, and 31 cm RS to improve yield and profit compared to current management practices.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 249
Author(s):  
Emmanuel Frossard ◽  
Frank Liebisch ◽  
Valérie Kouamé Hgaza ◽  
Delwendé Innocent Kiba ◽  
Norbert Kirchgessner ◽  
...  

New management practices must be developed to improve yam productivity. By allowing non-destructive analyses of important plant traits, image-based phenotyping techniques could help developing such practices. Our objective was to determine the potential of image-based phenotyping methods to assess traits relevant for tuber yield formation in yam grown in the glasshouse and in the field. We took plant and leaf pictures with consumer cameras. We used the numbers of image pixels to derive the shoot biomass and the total leaf surface and calculated the ‘triangular greenness index’ (TGI) which is an indicator of the leaf chlorophyll content. Under glasshouse conditions, the number of pixels obtained from nadir view (view from the top) was positively correlated to shoot biomass, and total leaf surface, while the TGI was negatively correlated to the SPAD values and nitrogen (N) content of diagnostic leaves. Pictures taken from nadir view in the field showed an increase in soil surface cover and a decrease in TGI with time. TGI was negatively correlated to SPAD values measured on diagnostic leaves but was not correlated to leaf N content. In conclusion, these phenotyping techniques deliver relevant results but need to be further developed and validated for application in yam.


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