in order to evaluate the effects of xanthium strumarium or amaranthus retroflexus competition under unsprayed and sprayed (half the recommended rate of imazethapyr) on canopy architecture of weed and soybean, field experiment was conducted at the research farm of university of tehran, during the growing season of 2007 and 2008. the experimental design was factorial based on randomized complete ...

Increased soybean seed cost in recent years has generated interest in reducing seeding rates to maintain consistent economic returns. However, low seeding rates result in reduced established plant stands with slower canopy development, and canopy development is touted as an important element of integrated weed management (IWM). IWM practices have become even more important to slow the developme...

Evapotranspiration (ET) is a vital component of a field water balance. Canopy chambers are a promising method for determining crop ET because they are portable and applicable at a relatively small plot (m2) scale. Although a variety of canopy chamber designs have been proposed, field tests are still necessary to evaluate chamber performance for measuring crop ET. The objectives of this study ar...

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is the most economically important insect pest of soybean in the north central United States. Scouting-based integrated pest management (IPM) programs could become more efficient and more widely adopted by using plant spectral reflectance to estimate soybean aphid injury. Our objective was to determine whether plant spectral reflec...

Light intensity intercepted by the soybean canopy during the reproductive period is an important environmental factor determining soybean yield components and grain yield. A 2-year field experiment was conducted to investigate the effects of light enrichment and its interaction with planting density on yield formation of soybean cultivars. Light enrichment increased seed yield per plant and yie...

Soybean canopy outline is an important trait used to understand light interception ability, canopy closure rates, row spacing response, which in turn affects crop growth and yield, and directly impacts weed species germination and emergence. In this manuscript, we utilize a methodology that constructs geometric measures of the soybean canopy outline from digital images of canopies, allowing vis...

in order to determine the role of plant leaf area in radiation distribution within the canopy and a better understanding of how crops and weeds intercept light a study of the complexity of plants is necessary. the  effect of intercropping on leaf area distribution and dry matter accumulation in corn, soybean and weeds canopy was studied in a  field experiment at a research field of tehran unive...

• Here, we investigated the effects of increasing concentrations of ozone ([O(3)]) on soybean canopy-scale fluxes of heat and water vapor, as well as water use efficiency (WUE), at the Soybean Free Air Concentration Enrichment (SoyFACE) facility. • Micrometeorological measurements were made to determine the net radiation (R(n)), sensible heat flux (H), soil heat flux (G(0)) and latent heat flux...

introduction amount and vertical distribution of leaf area are essential for estimating interception and utilization of solar radiation of crop canopies and, consequently dry matter accumulation (valentinuz & tollenaar, 2006). vertical distribution of leaf area is leaf areas per horizontal layers, based on height (boedhram et al., 2001). above-ground biomass is one of the central traits in func...

Digital imagery can help to quantify seasonal changes in desirable crop phenotypes that can be treated as quantitative traits. Because limitations in precise and functional phenotyping restrain genetic improvement in the postgenomic era, imagery-based phenomics could become the next breakthrough to accelerate genetic gains in field crops. Whereas many phenomic studies focus on exploratory analy...