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Action | Time (days) | Purpose |
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Establish perennial grasses | 60 | Create suppressive conditions |
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1st growth cycle: single seed of B. tectorum sown between established perennial grasses (in competition) and alone (without competition) | 89 | |
1st growth cycle harvest: perennials clipped at 15 cm above soil surface and B. tectorum clipped at soil surface. Dry tissue weights measured | 1 |
Quantify the degree of suppression by three perennial grasses in competition with B. tectorum relative to B. tectorum grown without competition |
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2nd growth cycle: repeat 1st cycle planting protocols | 78 | |
2nd growth cycle harvest: Repeat 1st cycle harvest protocols | 1 |
Clipping perennial grasses simulates the effects of herbivory on suppression. Removal of perennial above-ground mass will test the effect of declining soil resources on suppression |
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3rd growth cycle: excavate 400 g soil from beneath clipped B. tectorum, mix with 4 g activated carbon, and return to rhizotrons, then repeat planting protocols | 81 | |
3rd growth cycle harvest: repeat 1st cycle harvest protocols | 1 |
Test if activated carbon addition affects suppression via amelioration of allelopathy. Disturbance will create root-free soil space and increase biological soil space, at least initially |
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4th growth cycle: repeat planting protocols then, after emergence of B. tectorum, top-dress each rhizotron soil with a complete fertilizer solution (Rapid Gro) containing 82 mM N, 6.7 mM P, and 9.0 mM K and micronutrients in a 500 mL solution added in 100 mL increments over 5 weeks | 84 | |
4th growth cycle harvest: repeat 1st cycle harvest protocols | 1 |
Test if suppression is partly due to lack of nutrients |
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5th growth cycle: perennial grasses cut below growing nodes to kill plant | 83 | |
5th growth cycle harvest: B. tectorum clipped at soil surface. Soil samples taken | 1 |
Test how perennial grass death affects suppression |
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