Centre for Plant & Water Science - Central Queensland University

Centre for Plant & Water Science 2008 Annual Report
OXYGATION OF SUB-SURFACE DRIP IRRIGATED PINEAPPLE,
COTTON AND WHEAT
SUMMARY
Wheat followed a cotton crop in two soil types in concrete tubs, and itself was followed by a
subsequent cotton crop. The effects of oxygation on the wheat suggest an increase in biomass which
was associated with an increase in the leaf chlorophyll content, more ears per unit area, and
reduced canopy temperature. A large-scale replicated trial on an existing pineapple crop in Yeppoon
compared oxygation with no oxygation, both with subsurface drip irrigation. Total yield, but not
marketable yield, was increased with oxygation, and some fruit quality parameters were also better
with oxygation.
Following on from the 2007/8 cotton crop (see Annual Report 2007) a wheat crop was planted, using
two methods for aerating the irrigation water (Mazzei and Seair). The wheat crop was harvested
before grain maturity to allow for planting of the subsequent cotton crop with the GM planting
window. There was a significantly higher leaf chlorophyll concentration for Mazzei followed by
Seair and control (Table 1). The number of wheat ears, leaf dry weight and total dry matter were
significantly greater on the vertisol whereas chlorophyll content was greater on the ferrosol.
Table 1. Effect of different oxygation methods and soil types of growth parameters and yield
components of wheat
Treatments
Oxygation
Soil type
Levels
WUEi
Leaf Leaf
Number
(mol
Weight of dry
chlorophyll water
of
CWSI 1 CO
matter (g m -2 )
2
concentration potential
Ears
/ mmol
(SPAD units) (-kPa)
(m 2 )
H 2 O)
Ear Leaf Stem
Control 37.1 1000 0.22 5.96 329.4 260.0 136.1 308.9
Mazzei 41.0 1040 0.18 6.54 357.1 289.2 160.2 313.2
Seair 38.9 1130 0.18 5.96 337.5 271.0 132.1 322.4
LSD (10 df) 2 2.3 197 0.10 0.94 57.5 58.2 38.7 69.0
Vertisol 37.5 1090 0.21 6.36 383.4 328.5 194.3 382.5
Ferrosol 40.9 1040 0.17 5.99 302.2 221.6 93.0 248.6
LSD (10 df) 1.8 158 0.08 0.75 46.2 46.7 31.1 55.4
1 Crop water stress index; 2 LSD (P