Claim · model-written summary
Although some cultivars showed initial lower growth rates, crop yield did not decrease.
Verbatim
e0“Although some cultivars had shown initial signs of lower growth rates, there was no decrease in crop yield”
Title
Weed interference and weed control in cole crops and onion
Bitterlich, Iris cIRcle (University of British Columbia) 2010. doi:10.14288/1.0098094
Other claims from this paper (19)
- Intervention effect Lamb's-quarters at 3 to 15 plants m-2 began to affect broccoli growth 28 to 36 days after seeding.
- Association Decreases in broccoli growth increased with weed density and with time after seeding.
- Intervention effect One lamb's-quarters plant m-2 could reduce total broccoli yield by 18 to 20 percent in a fitted yield model.
- Intervention effect One lamb's-quarters plant m-2 could reduce marketable broccoli yield by 22 to 37 percent in a fitted yield model.
- Mechanism Lamb's-quarters reduced total broccoli yield through lower average head weight, not through fewer heads per plot.
- Mechanism The weed reduced marketable broccoli yield by lowering both average head weight and the number of heads per plot.
- Intervention effect Liquid ammonium nitrate controlled shepherd's-purse, chickweed and cudweed.
- Intervention effect Liquid ammonium nitrate controlled redroot pigweed.
- Intervention effect Liquid ammonium nitrate did not control lamb's-quarters, purslane and annual bluegrass.
- Observation Corn spurry (Spergula arvensis) varied in its tolerance to ammonium nitrate burning.
- Intervention effect Shepherd's-purse at the densities tested did not significantly reduce broccoli yield.
- Observation Initial ammonium nitrate weed control in broccoli was reduced over time.
- Intervention effect Growth rates of Lunet, SGI, Elgon and Matra initially decreased under ammonium nitrate burning but the plants recovered.
- Intervention effect Growth rates of White Lisbon, Emperor and Early Marvel were largely unaffected by ammonium nitrate burning.
- Intervention effect Ammonium nitrate retention and salt injury were far greater on cabbage leaves stripped of epicuticular wax than on unstripped leaves.
- Observation Tolerant crop and weed species had leaf surfaces completely covered with a crystalline wax layer, while susceptible species had little or no epicuticular wax.
- Mechanism Trichomes on susceptible species may increase ammonium nitrate retention and salt injury.
- Observation Ammonium nitrate reduced weed populations by 70 percent in 1987.
- Observation Onion and broccoli crop plants did not reach a harvestable size under the weed competition in 1987.
Prunus cerasus
Oryza sativa
Triticum aestivum.jpg?width=60){kind=small}
Hordeum vulgare
Zea mays