Low population counts averaging 124 plants/m2 were a surprise as no-one does intensive counts any more – the last ones I did were back in the 1980’s when we were developing Ricecheck.

The 124 plants/m2 is equivalent to only 20 per cent germination assuming a sowing rate of 160kg/ha Sherpa. A table in the Finley Discussion Groups Ricecheck Recommendations indicates seeds sown per m2 at 100kg/ha for each variety.

Rice yields of the Finley Discussion Group farmers over the last three years are well above the EMV SunRice yield average and last season the top 11 averaged 13.4t/ha.

The farmers have recorded good establishment for most crops over the three years for all sowing methods so I presume this season’s poor populations are a one off.

We have specialised in factors affecting rice establishment and developing practices to overcome them with results published in the recent Spring Edition of the Farmers Newsletter.

The rice population check is 180-250 plants/m2.

Of the 15 crops only seven crops or 46 per cent achieved the check. Of the five aerial pre-germinated crops two crops did not achieve the check.

None of the five dry broadcast crops adopted the check and of the five drill crops one crop did not achieve the check.

The poor adoption from dry broadcast is hard to explain. It’s become the most popular method because it’s been the highest yielding method and $40/ha cheaper cost than aerial pre-germinated. Last season six of the top 11 yields (averaging 13.4t/ha) were dry broadcast and the average yield was 11.6t/ha compared to 11.1t/ha for aerial pre-germinated.  

At the recent discussion group meetings farmers said it was a great start to the season but the poor establishment particularly for dry broadcasting tells another story - we will get to the bottom of it at the next meetings. It may be from the earlier winter crop harvest which has left less time to manage rice. If it’s from seed sinkage why didn’t it affect the group crops in previous seasons?

A bright spot for the poorer crops was the uniformity of the plant stands hence high yields are still possible.

The main establishment issue was the two high wind and gusty days in mid October and in late October/ early November when gusts were over 40kph. This played havoc with crops at the three to four leaf stage particularly in bigger north south oriented bays.

Clumping was common. Smaller bays or east west bays had much less trouble.

Some crops and bays had green algae coloured water related to poor stubble ash breakdown and incorporation or inadequate incorporation dry residue. I couldn’t see the soil in some of these bays so the green water acted like muddy water reducing water temperatures and plant vigour. Following the five day fillup for herbicide application water should be allowed to drop without exposing high areas.

I observed green algae and a green brown algal skin on the soil surface toxic to germinating seeds in a number of crops This flakes off and floats as brown slime and was identified in 2003 by Adrienne Grant as iron oxidising bacteria so bluestone has no effect. Farmers using bluestone for snail control have noticed a beneficial effect on green algae.  Higher temperatures in October are thought to have promoted the algae.

Flocks of ibis feeding on aquatic worms were very common turning soil into a structure -less ooze making it hard for plants to get an anchorage.

Both project and discussion group farmers had problems with hard soil for drill sowing. Many farmer drills and contractors were not able to drill seed 3cm deep as the soil was too hard. Shallow sowing at 1 to 2cm resulted in seeds not germinating or shoots stuck under a crust. This necessitated three flushes to get rice emerged. Farmers need to make an autumn decision on drill sowing intent and use one of or a combination of discing, Kelly chains, chisels and wideboards to soften the soil for sowing.

The lowest plant populations had a combination of factors- wind clumping, algal skin, aquatic worms and over-deep water. We have developed a package of key practices for successful dry broadcasting and I am suspicious farmers may not have adhered to some of these practices.