Proceedings of the Sixty-first Annual Meeting of the Northeastern ...

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EFFECTS OF FLOATING ROW COVER ON WEED EMERGENCE AND STALE SEED
BED PERFORMANCE. D.C. Brainard, R.R. Bellinder and V. Kumar, Cornell Univ.,
Ithaca, NY.
ABSTRACT
Floating row covers can be valuable for season extension and for protecting
crops from insects such as flea beetles. However, row covers complicate weed
management since they improve conditions for germination and growth of weeds, and
require removal for cultivation or herbicide applications. The objectives of this research
were to (i) assess the effect of floating row covers on soil temperature and weed
emergence, and (ii) to evaluate whether a stale seed bed used either alone or in
combination with row cover before crop planting could reduce weed emergence after
crop planting. Four field trials were conducted in central NY beginning in either late May
or early July, 2005 and 2006. No crops were grown, but crop planting was simulated
using a Monosem seeder. Each trial consisted of a total of six treatments arranged in
RCBD. After simulated crop planting, plots were either left bare, or covered with floating
row cover (Agribon 19). For each of these post-planting treatments, three pre-planting
treatments were examined: (i) a conventional (CONV) treatment in which plots were
harrowed immediately before simulated crop planting, (ii) a stale seed bed (SSB)
treatment in which beds were prepared 2-3 wk in advance, and emerged weeds killed
with Roundup (0.05 lbs ai/A) immediately before simulated crop planting, and (iii) a stale
seed bed with row cover (SSB+RC) treatment, which was the same as the SSB
treatment, except that plots were covered with floating row cover before simulated crop
planting. Average soil temperatures (at 3 cm depth over a two wk interval) ranged from
0 to 3.5 C higher under the floating row cover compared to bare soil, with an average
difference of 2.2 C. Temperature differences were highest in mid afternoon and on
sunny days, reaching as much as 12 C. Higher temperatures under row covers resulted
in 2- to 200-fold increases in weed emergence before simulated crop planting compared
to bare soil, depending on trial and weed species. Averaged over all trials, weed
emergence two wk after simulated crop planting was reduced 38% in SSB treatments,
and 61% in SSB+RC treatments compared to CONV treatments. In two trials, SSB+RC
treatments resulted in greater than 90% reduction in weed emergence compared to
CONV controls. Our results demonstrate that (i) when used after crop planting, floating
row covers can exacerbate weed management problems through stimulation of weed
emergence, but that (ii) when used before crop planting, floating row covers can
enhance the performance of stale seed beds and reduce emergence of weeds with the
crop.
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