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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #298051

Research Project: Multifunctional Farms and Landscapes to Enhance Ecosystem Services

Location: Pasture Systems & Watershed Management Research

Title: Water competition among mixed species in the Northeast US

item CAMARGO, GUSTAVO - Pennsylvania State University
item KEMANIAN, ARMEN - Pennsylvania State University
item RICHARD, TOM - Pennsylvania State University
item Goslee, Sarah
item Skinner, Robert

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/12/2013
Publication Date: 11/3/2013
Citation: Camargo, G., Kemanian, A., Richard, T., Goslee, S.C., Skinner, R.H. 2013. Water competition among mixed species in the Northeast US. ASA-CSSA-SSSA Annual Meeting Abstracts. p 1.

Interpretive Summary:

Technical Abstract: Competition for water and nutrients by plants plays a major role in controlling multispecies pastures growth, resource use, and soil availability of reactive forms of nutrients. However, to describe and model competition with process based models many questions remain unanswered. The goal of this investigation is to unravel the mechanisms controlling competition for water among roots of different plants. We report results for an experiment with the model annual plants maize (Zea mays L.) and sunflower (Helianthus annuus L.). Plants were grown in rhizotrons in five treatments. Treatments consisted pure and mixed plants. To introduce water competition, plants were allowed to progressively advance towards water deficit stress, with competition for light and nutrient suppressed through plant spacing and high soil fertility. Daily transpiration and leaf area were measured during the stress period. Measurements of soil, xylem and leaf water potential were obtained in the end the stress period. Plants were sampled at three different times. Sunflower had a higher daily and cumulative transpiration rate than maize. Sunflower maintained a gradient of -200 to 1,100 J/kg between the soil and transpiring leaves, and maize a gradient of -115 to 930 J/kg. Since transpiration was higher in sunflower, resistance to water flow in this species was approximately a half of maize. Rhizotrons with sunflower and maize loss water at a rate in-between that of rhizotrons with pure stands. Results indicate that sunflower will outcompete maize if sharing the same soil because of its profligate use of water, a proposition that will be tested with an algorithm that simulates competition. Complementary research is currently being conducted with mixed pastures, where understanding competition is critical to predict the productivity and water use of multispecies stands.