ABCD / WQ Risk
Bp Low- Mod
Cf Mod
P2R WQ Risk framework Strategy **
The amounts of N and P applied are optimal for crops on each major soil type and / or management zone .
Nitrogen fertiliser rate for each plant crop and its subsequent ratoons are derived from soil tests and the Six Easy Steps method . Rates are based on district yield potential with adjustments made according to the soil N mineralisation index ( based on organic carbon percentage ). Deductions are made for other significant sources of N including from irrigation water , mill mud and legumes .
NUE and Rate Rules Plant Ratoons Notes
6ES DYP and NUE < 1.4
6ES District Yield Potential ( DYP )
NUE = 1.4 NUE = 1.4 Calc from modelled yield potential
120-180 |
160-220 |
6ES DYP with adjustment for soil |
|
|
OC |
Cp Mod
Df High
N fertiliser rate typically exceeds the Six Easy Steps baseline application rate . Non-compliant with regulated method for calculating optimum N rate .
> 6ES DYP 220 220 Set rate , as for previous modelling
> 6ES DYP and NUE >= 1.8
NUE = 1.5 NUE = 1.9 Calc from modelled yield potential
Note that phosphorus and mill mud application rates are also being considered but yet to be finalised . Cover and tillage management
Leveling – Leveling will occur every 2-3 crop cycles in the model and will account for pre-wet season and post-wet season differences in the effects of levelling ( if in wet season , more cultivations needed to follow it ).
Fallow – Fallow is defined as anything other than sugarcane . Options could include : sugarcane trash left on ground ( i . e . ratoon cut green ), bare fallow , maintain some cover ( some grasses or weeds ), legume ( green manure ), legume ( harvested ) and other crops . Mungbeans are the most common legume fallow crop in the Lower Burdekin , however , there are now soybean varieties available that will grow in the fallow periods identified for the model . It is recognised that there is an increasing area under ‘ other crops ’, although it is currently a relatively small proportion of area , maybe 300ha versus the 3000ha with legumes ; there is potential that this will increase and will be considered for future modelling updates .
Green Cane Trash Blanketing – It is noted that with the current weighting of 40 per cent in the P2R WQ Risk Framework , no grower can achieve better than a Bp score for soil management unless green cane trash blanketing is adopted . It is therefore only included in the Af management class .
34