GROWER WORKSHOPS – REEF REGULATIONS
As a result of workshops held last month there were a few questions raised by members which KCGO sought clarification from Dept of Environment and Science in relation to regulations.
Question & Responses are as follows:
1. Fallow Period – What is deemed to be the commencement of a fallow period? Some members were of the opinion period commenced once sugar cane was harvested, whereas others were of the opinion it would be from when alternate crop was removed and paddock became “bare”.
Response – Generally the “fallow” is the rest between sugarcane crops and the legume cover crop is part of the fallow period. So not so much about measuring the period of bare ground, more of the period between cane crops harvested and planted.
2. Block Size – Is there a minimum area size in relation to not having to obtain a soil test on a fallow block?
Response – there is no size factor in the soil testing method. Soil sampling guidelines of Prescribed Methodology for Sugarcane Cultivation (PMSC) makes mention of:
• The design of a soil sampling plan involves selecting an area for soil sampling that represents the fertility status of the blocks being planted on a growers farm that year. A single block can represent the fertility status of a number of plant cane blocks belonging to the same soil grouping.
• Separate soil samples must be taken from blocks that represent those that have (a) received and (b) not received previous applications of mill by-products.
• For plant blocks with the same soil types or soil groupings, and that are farmed the same way, select a block of average productivity that a grower considers is representative of the rest of the plant blocks in the group.
• An example in that if block is 1 hectare, at least 20 core samples should be collected for the composite sample.
It is also worth clarifying with growers that they do need to keep with their records a farm soil map that verifies the soil types are the same.
3. Crop Failure – In the event of a crop failure due to an unforeseen event eg. pest (wallabies/deer/pigs), disease infestation or climatic, be it plant or ratoon, with fertiliser having been correctly applied in terms of “Prescribed Methodology For Sugarcane Cultivation (PMSC) and as a result of said event effected block/s need to be replanted/fertiliser reapplied. What would be the process be for grower in this instance given fertiliser has been previously applied in terms of the methodology to meet reef regulations?
Response – Growers should do a second soil test in this case. The only way to confidently assess how much of the potentially available N has been lost is to measure mineral N (ammonium-N plus nitrate-N) in the 0-20cm soil layer just prior to crop planting. This amount of mineral N can then be subtracted from the crop N requirements (based on District Yield Potential) to calculate fertiliser N required. As fertiliser has already been applied to the crop, the soil nutrient status will have changed. Growers will therefore not be able to determine an appropriate amount of fertiliser to apply to the second crop using the previous soil test.
• For plant/replant of the damaged area – This is a new plant crop. Under condition SC6 of the Agricultural ERA standard for sugarcane, growers will need a new soil test before replanting.
• For ratooning of the damaged area – Essentially a new ratoon. Fertiliser can be applied at the regulated ratoon rate. A new soil test is not required but it is recommended, particularly following flood events where nitrate may have leached out of the soil.
• Where an N and P budget has been prepared, it will need to be amended. Under condition SC14 of the Agricultural ERA Standard, review and update must be “at least annually” but can be more frequently. Under condition SC15(d), the update must consider “any other changes that may affect the amount of fertiliser calculated.”
Les Elphinstone
Manager KCGO