Implications of delayed <i>Echinochloa</i> spp. germination and duration of competition for integrated weed management in water‐seeded rice

Gibson, K. D.; Fischer, Albert J.; Foin, Theodore C.; Hill, James E.

doi:10.1046/j.1365-3180.2002.00295.x

Cited by 103 publications

(82 citation statements)

References 18 publications

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“…Rice relative cover increased from 2013 to 2014 over all treatments, yet the increase in 2014 at canopy closure did not correlate with an increase in rice biomass at harvest in 2014. This response confirms earlier research in California that showed competition with late watergrass after the critical period of competition (30 DAS) further decreased rice yields (Gibson et al 2002). It is significant to note that despite statistically similar initial populations of watergrass species in all fields (unpublished data), rice cover and biomass were lowest in the DS-AWD compared with the water-seeded treatments, either indicating that the watergrass species are more competitive against rice under anaerobic conditions or confirming that rice is less competitive with weeds under anaerobic environments (Bhagat et al 1996).…”

Section: Resultssupporting

confidence: 91%

Weed Community Dynamics and System Productivity in Alternative Irrigation Systems in California Rice

2016

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Over the last 10 yr, California has experienced a series of ever-worsening droughts. Rice, traditionally a flooded crop, has come under increasing scrutiny with respect to its water use, leading to proposals to evaluate alternative irrigation systems. For growers, weed competition is one of the most limiting factors to maintaining high yields, so understanding the shifts among species in weed communities under the proposed alternative irrigation systems is vital. A field study was conducted from 2012 to 2014 to compare weed population and growth dynamics with three irrigation systems: (1) a conventional water-seeded control system (WS-Control), with a permanent flood of 10 to 15 cm from planting until 1 mo prior to harvest; (2) a water-seeded alternate wet and dry system (WS-AWD), with the field flooded from planting until canopy closure, after which floodwater was allowed to subside and the field was reflooded when the soil volumetric water content reached 35%; and (3) a drill-seeded alternate wet and dry system (DS-AWD), with rice drill seeded and then flush irrigated to establish the crop, after which the field was flooded until canopy closure and then underwent an alternate wet and dry (AWD) treatment similar to WS-AWD. In the AWD treatments, there were two drying periods, neither of which occurred after the heading stage. The dynamics of major weed species were evaluated using plant density counts (2012) and relative cover and biomass (2013 and 2014). Grasses (sprangletop and watergrass species) dominated the DS-AWD system; sedges, broadleaves, and grasses dominated both WS systems. The WS-AWD system increased smallflower umbrella sedge relative cover at canopy closure, relative dry weight at harvest, and percent frequency when compared with the WS-Control system. Yields did not differ across treatments when weeds were controlled (P > 0.05); in the absence of herbicides, yields in the WS-AWD were equivalent to the WS-Control (ranging from 40 to 65% of the herbicide-treated yields) and zero in the DS-AWD due to weed pressure. Nomenclature: bearded sprangletop, Leptochloa fusca (L.) Kunth N. Snow; ducksalad, Heteranthera rotundifolia (Kunth) Griseb.; redstem, Ammannia coccinea Rottb.; ricefield bulrush, Schoenoplectus mucronatus (L.) Palla; smallflower umbrella sedge, Cyperus difformis L.; rice (Oryza sativa L.).

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Section: Resultssupporting

confidence: 91%

Weed Community Dynamics and System Productivity in Alternative Irrigation Systems in California Rice

2016

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“…Evaluation timing was selected based on the critical period of competition for watergrass in rice, which is 30 DAS (Gibson et al 2002). The difference in assessment timing from the calibration site was due to efforts to standardize the assessment timing for ease of use by growers.…”

Section: Site Characterization and Experimental Setupmentioning

confidence: 99%

Predicting Yield Losses in Rice Mixed-Weed Species Infestations in California

2016

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Although many pests constrain rice production, weeds are considered to be the major barrier to achieving optimal yields. A predictive model based on naturally occurring mixed-species infestations in the field would enable growers to target the specific weed group that is the greatest contributor to yield loss, but as of now no such models are available. In 2013 and 2014, two empirical hyperbolic models were tested using the relative cover at canopy closure of groups of weed species as independent variables: grasses, sedges, broadleaves, grasses and sedges combined, grasses and broadleaves combined, and all weed species combined. Models were calibrated using data from experiments conducted at the California Rice Experiment Station, in Biggs, CA, and validated across four sites over 2 years, for a total of 7 site-year combinations. Of the three major weed groups, grasses, sedges, and broadleaves, the only groups positively related to yield loss in the multispecies infestation were grasses. At the model calibration site, grasses and sedges combined best predicted yield loss (corrected Akaike information criterion [AICc] = −21.5) in 2013, and grasses alone best predicted yield loss (AICc = −19.0) in 2014. Across the validation sites, the model using grasses and sedges combined was the best predictor in 5 out of 7 site-years. Accuracy of the predicted values at the model validation sites ranged from 6% mean average error to 17% mean average error. No single model and set of parameters accurately predicted losses across all years and locations, but relative cover of grasses and sedges combined at canopy closure was the best estimate over the most sites and years. Nomenclature: Rice, Oryza sativa L.

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“…exhibit great competition effects towards rice, especially during early stages of cultivation. Gibson et al (2002), for example, found that the competition established by Echinochloa spp. is significantly lower if a rice field is maintained free from these weeds during the first 30 days after seeding.…”

Section: Introductionmentioning

confidence: 99%

Effect of salinity on Echinochloa crus-galli germination as affected by herbicide resistance

Serra¹,

Fogliatto²,

Vidotto³

2018

Ital J Agronomy

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Salinity is one of the major abiotic stresses that may affect yield and quality of crops. Salinization, in combination with the presence of aggressive weeds, such as barnyard grass (Echinochloa spp.), can be considered one of the factors responsible for reducing yield in rice fields. The aims of the study were to evaluate the salt effect on germination and first seedling growth of six different Italian common barnyard grass (E. crus-galli) populations (three sensitive and three resistant to ALS-inhibitor herbicides) and to verify the presence of differences in salt response between populations sensitive and resistant to the ALS-inhibitor herbicides. Germination tests were conducted under nine different NaCl concentrations (from 0 mM to 400 mM). Significant differences in germination capacity were found between sensitive and resistant populations from 0 mM to 250 mM NaCl; in particular, germination capacity of the sensitive populations was higher (up to 90%) than that of the resistant ones (about 70%). The increase in salinity over 250 mM reduced progressively the germination capacity: from 300 mM onwards, no significant differences were found between sensitive and resistant populations and the germination resulted inhibited for two of them (one sensitive and one resistant). Speed of germination and root and shoot length of seedlings were also inversely related to salt concentration. Time required for achieving 50% of final germination capacity was extended from about three days at 0 mM NaCl up to about 10-12 days at 400 mM NaCl. Root length and shoot length ranged from 9.88 cm and 6.16 cm, at 0 mM NaCl, to 0.36 cm and 0.41 cm, at 400 mM NaCl. According to the results, there is no a clear evidence that response to saline conditions was related to resistance towards ALS-inhibitor herbicides, as in some cases significant differences were found between populations showing a similar herbicide sensitivity. Responses of barnyard grass to salinity are may play a role in the importance of this weed in future scenarios of salt intrusion: for example, a lower speed of germination at increasing salt levels could suggest a delayed emergence of this weed during crop establishment and first growth. To evaluate the real consequences in terms of competitions towards the crop, future studies are needed for assessing the response to salinity of the main rice varieties cultivated in the environment in which the E. crus-galli populations tested in this study were collected.

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Implications of delayed Echinochloa spp. germination and duration of competition for integrated weed management in water‐seeded rice

Cited by 103 publications

References 18 publications

Weed Community Dynamics and System Productivity in Alternative Irrigation Systems in California Rice

Weed Community Dynamics and System Productivity in Alternative Irrigation Systems in California Rice

Predicting Yield Losses in Rice Mixed-Weed Species Infestations in California

Effect of salinity on Echinochloa crus-galli germination as affected by herbicide resistance

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