Author
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Teasdale, John |
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MOHLER, C - CORNELL UNIVERSITY |
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Submitted to: International Weed Control Congress Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 6/6/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Mulches on the soil surface are known to suppress weed emergence but there is little research that describes the quantitative relationships between emergence and mulch properties. Data from experiments determining the emergence of four annual weed species through seven mulch materials applied at six rates were fitted to various measures of mulch physical characteristics. Mulch materials, in order from lowest to highest surface area to mass ratio, were bark chips, corn (Zea mays L.) stalks, rye (Secale cereale L.), crimson clover (Trifolium incarnatum L.), hairy vetch (Vicia villosa Roth), oak (Quercus spp.) leaves, and landscape fabric strips. Weed emergence was successfully predicted by models based on mulch properties alone regardless of mulch material, suggesting the fundamental importance of these properties for determining weed emergence. The best fitting models included the properties "mulch area index" and "solid volume fraction". Mulch area index, defined as the projected area of mulch elements per unit soil (analogous to leaf area index), was a pivotal property for understanding weed emergence through mulches and for quantitatively defining mulch properties. Solid volume fraction, defined as the fraction of mulch space filled by mulch material, also contributed significantly to models defining seedling emergence through mulches. The order of weed species sensitivity to mulches (Amaranthus retroflexus L.>Chenopodium album L.>Setaria faberi Herrm.>Abutilon theophrasti Medicus) inversely correlated with the order of seed size suggesting that the capacity of seedlings to grow through empty mulch space before exhausting seed reserves was an important factor contributing to emergence success. |
