Huong T. X. Nguyen

Huong T. X. Nguyen

An agroecologist who cares deeply about food justice

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current_work

publications

Weed seedbank diversity and sustainability indicators for simple and more diverse cropping systems

Published in Weed Research, 2021

We evaluated the hypothesis that weed seedbank diversity can serve as an indicator of agroecosystem sustainability using long-term field data from Iowa, USA. We suggest that while there was no cause-and-effect relationship between greater weed seedbank diversity and improved agroecosystem sustainability in agronomic, economic and environmental dimensions, all of these responses were driven in a parallel manner by cropping system diversification. Consequently, weed seedbank diversity may indeed be a useful agroecosystem sustainability indicator.

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How can cover crops contribute to weed management? A modelling approach illustrated with rye (Secale cereale) and Amaranthus tuberculatus

Published in Weed Research, 2021

We report the results of modelling analyses that investigated how a cover crop could affect the population dynamics of Amaranthus tuberculatus (Moq.) J.D. Sauer (waterhemp), an annual dicotyledonous species that is a major problem in maize and soyabean fields in the central USA. While cover crops did not replace the need for other control strategies for A. tuberculatus, they could complement them. Relative to cover crops, greater benefits for A. tuberculatus management might be gained using diverse sequences of cash crops. Possible synergies between cover crops and diversified crop rotations should be explored in both field experiments and modelling analyses.

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Impact of Cropping System Diversification on Vegetative and Reproductive Characteristics of Waterhemp (Amaranthus tuberculatus)

Published in Frontiers in Agronomy, 2022

We modeled the relationship between the aboveground mass and fecundity of waterhemp under the presence of four crop species within three crop rotation systems, namely, a 2-year sequence of corn and soybean; a 3-year sequence of corn, soybean, and oat intercropped with red clover; and a 4-year sequence of corn, soybean, oat intercropped with alfalfa, and alfalfa. Rotation system and crop phase within rotation system had significant effects on all the response variables but weed control regime on some. The sex ratios at maturity were slightly female-biased in oat and alfalfa. Mature waterhemp plants were larger in corn and soybean than in oat and alfalfa. Oat and alfalfa were planted earlier than corn and soybean and successfully competed for resources against waterhemp despite the absence of herbicide or interrow cultivation. Frequent hay cuts in alfalfa served as physical weed control and contributed to suppressing waterhemp and other weeds substantially. Code at https://github.com/hnguyen19/AMATA-fecundity

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Weed Community Composition in Simple and More Diverse Cropping Systems

Published in Frontiers in Agronomy, 2022

Weed communities in three cropping systems suitable for the Midwestern USA were studied from 2017 to 2020 to examine how crop diversification and the intensity of herbicide use affected weed community diversity, stand density, and aboveground mass. A baseline 2-year cropping system with corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) grown in alternate years was diversified with cool-season crops, namely oat (Avena sativa L.), red clover (Trifolium pratense L.), and alfalfa (Medicago sativa L.) in 3-and 4-year systems. Herbicide was not applied in the cool-season crops. Changing weed management regime from broadcast to banded application and interrow cultivation in corn and omitting herbicide in cool-season crops of the 3- and 4-year rotations resulted in an overall reduction of herbicide a.i mass. The reduction in the mass of herbicide active ingredients was associated with increases in weed stand density, aboveground mass, and community diversity. Increased weed abundance under herbicide mass reduction was not associated with crop yield loss. In the cool-season crops phases of the 3- and 4-year rotations, weed emergence was increased but weed growth was not, as compared with the warm-season crop environments. The dominance of aggressive weed species such as common waterhemp (Amaranthus tuberculatus (Moq ex DC) J.D. Sauer) and common lambsquarter (Chenopodium album L.) tended to be greater in corn and soybean phases of the rotations than in oat, red clover, and alfalfa. Code at https://github.com/hnguyen19/Weed-community

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talks

Students’ awareness on the sustainability of the ecosystem

Published:

An annual conference for students in 20 sister agricultural universities. I presented findings on two projects targeting the mountainous areas residents. The first project concerned sorghum breeding for improved nutrient content. The second project concerned socio-economic strategies for empowering women of two ethnic minorities.