This experiment was conducted under commercial conditions
on a grower’s property to examine the effect of planting date on
emergence and subsequent growth of cotton.
Soil temperatures were 1–2 ◦C greater under the film with little
difference between the control and spray-on for all planting dates
(Fig. 4). The minimum soil temperature was on average 2 ◦C higher under the film and 0.1 ◦C cooler under the spray-on compared with
the control for all plant dates (Table 2).
Soil water potential was similar under all treatments over the
period from planting to emergence (15–17 days after planting) at all
planting dates (Fig. 5). For planting 3 there was a greater decrease
in soil water potential under the control (−170 kPa) and spray-on
(−450 kPa) compared with the film (Fig. 5c); this site was abandoned due to heavy weed infestation under the film. Planting 2 was
a dry planting with the seedbed wet up by irrigation (Fig. 5b), while
for the other planting dates cotton was planted into a wet seedbed.
The soil at 0.1 m nearly dried to the crop wilting point (−1200 kPa)
under the control, whereas the film only dried to −600 kPa at about
80 DAP (Fig. 5b).
There was a planting date by treatment interaction on lint yield
with significantly greater lint yield at the early planting date compared with the second planting date (3026 vs 1900 kg/ha) and with
yield being variable with treatments (Table 5). Planting date also
significantly influenced fibre length and micronaire with increased
length and micronaire occurring with the later planting (Table 5).