Lessons from past floods good guide

Be prepared to get started on remedial work as soon as the water drains away.

It's been a challenging time for the many farmers in the lower North Island affected by floods, but lessons learned from previous years can help get pastures back on the road to recovery a bit quicker this time around, says Agriseeds lower North Island area manager Bruce Patterson.

The aftermath of severe floods in 2004 helped identify the best ways to get grass growing again as fast as possible when the water drains away.

Patterson, who has prepared a paddock recovery checklist which includes nine key steps, says the most important thing farmers can do is to make a good plan which covers their individual situation.

"These events are highly stressful and disruptive, especially as we head into spring and the start of lambing and calving.

"Farmers are already busy and this is the last thing they need or have time for. But if they do whatever is feasible and appropriate to restore paddocks now they will limit the effects of lost pasture production later in the season and give themselves the best chance of getting back on track as soon as possible."

CHECKLIST

Don't panic

* Plan, prepare and then act. That way you have the best chance of a successful result.

Check for signs of recovery

* Where no signs of grass growth have been visible after a week, consider the pasture dead. Weeds such as couch, browntop and creeping buttercup are much more likely to survive than ryegrass and clover.

Check the soil temperature

* This is the critical success factor for oversowing at this time of the year, and up until now it has been too low (less than 10C) in most areas. Seed needs soil temperatures of 10C or more for good germination.

Check the depth of sediment

* If it is less than 50mm a reasonable amount of existing pasture may be able to break through and start growing again. Several factors influence this so assess on a case-by-case basis.

When the ground is dry enough to be worked, silt 100mm to 150mm should be cultivated normally and sown in perennial or short-term ryegrass and clover.

Where silt exceeds 200mm wait for it to dry, spread it evenly across the paddock and use sub-soilers to bring buried soil to the surface.

Deeper deposits can be oversown if they are still damp otherwise wait until the silt is dry, break up the surface and drill short-term ryegrass or oats.

Check the smell

* Smelly silt or sediment is highly anaerobic and this can lead to poor germination and very low establishment of new seed. Anaerobic silts should be aerated or cultivated.

Check the silt fertility and pH

* Most flood deposits have little to no organic matter, low nitrogen and possibly low phosphorus. They also have a limited ability to store fertiliser so large applications are not recommended.

Fertilise

Use nitrogen to help surviving pastures recover from stress. Consult your fertiliser company representative for advice.

Cultivars

* Pick the right cultivars for re-sowing. Italian ryegrass (Tabu) and hybrid ryegrass (Shogun) seed have stronger vigour than perennial ryegrass, with stronger root growth and better establishment under adverse conditions. Cheap rye/clover mixes often used after these events cause difficulties in the future so make sure your money is well spent.

Slips

* For slips, pasture production is generally slow to recover. For best results oversow with smaller-leaved clovers (Apex and Weka) and cocksfoot (Safin) and add fertiliser as required (usually phosphorous and sulphur are most important).

Contact

Your retailer representative knows your farm and what the best solution might be.