WELL the winter cereal harvest is still happening and after our dry previous few months and the dreadful frost events just after mid-August, I believe we all will be very pleased that this season is nearly behind us.
However, we are still marketing our winter cereals and with our high screening levels, that is not easy to do and maximise profits. These screening levels are in general fairly high and with levels at more than 10%, it can lead to major reductions in our grain price, especially if targeting the export market. Unfortunately, small grain or screenings are an indication of lower flour yield in your wheat sample. So what causes these high screening levels or should I classify it as small grain?
For many years now our cereal breeders have been targeting higher yields. To achieve these higher yields the idea is to form and fill more grains of barley or wheat per square metre of crop. One way to do this is by increasing the tillering capability of a variety to obtain more seeds per square metre. Unfortunately, this higher tillering trait can lead to small grain. These higher tillering lines do not always lead to small grain, especially if the back end of the season is kind to the crops.
This year we even had moisture deficiency before flowering and coupled with the many days of warmer temperatures it exacerbated early maturity and subsequently small grain.
On the other hand researchers and breeders have developed seed lines of wheat and barley that have tiller development restrictors or inhibitions. In other words, just like some old grain sorghums had years ago in varieties of SM 8 and Gunsynd and to a certain extent G56, they were basically single stalk plants and not inclined to tiller, so sorghum seed planting rates had to be increased for yield maximisation.
Wheat and barley are not single stalk plants obviously, however there is great correlations between tillering, grain size, dry times at pre and post flowering and warm weather at flowering and grains fill.
A favourable growing time with good soil moisture available, towards flowering time is probably the key condition to keep screenings in check. Instead of heavy frosts on August 20-21, we receive 2-3inches of rain in this period, just like occurred in 2011. It may be worthwhile to investigate some varieties that have a restricted or semi restricted tillering capacity, however I suspect these varieties are not too popular in Queensland.
Sowing date is another consideration with your preferred variety. Plant too late with some varieties that you just happen to have in your silo, is never the most effective way to convert your stored soil moisture into maximum grain yields.
Nutritional balance is another obvious control agent. Nitrogen excess has always been considered a bogey man for small grain and big amounts dry matter produced and it certainly can be part of the problem.
So balancing your available nutrients with soil moisture is as usual, a very handy process to adhere to. I will not remind you all again about my zest for split application of nitrogen bandwagon in our grain crops.
So while we all rail against screenings in our sample, if the 2inches of rain had occurred in mid to late August, then I would not be writing and postulating about wheat and barley small grain levels in our samples.
I do believe for a host of reasons, that we need to get our varietal purity much improved and the planting date spot on for our chosen wheat or barley variety.
Paul McIntosh is a former manager of Landmark Emerald, now based on the Darling Downs.