What to plant in spring
SOME weeks ago I made a statement that over the years, farmers I know have planted a winter cereal crop and then gone straight to the Brisbane Exhibition.
Very late in the normally desirable winter planting dates, however the resultant grain yields were well over two tonne per hectare, to say nothing about the stubble left after harvest for heavy summer storms protection.
Much needed VAM, or Vesicular Arbuscular Mycorrhiza, encouraged also for various crops is a previous article by myself a couple of weeks ago, on establishing these very handy soil fungi.
We are in a much more desperate position now for not only grain crops, but fodder crops as well. So what are your best options when the rain comes, as we get closer to spring with warmer soil temps? All of us, including our livestock, would just be happy if any plant grew, be it weed or planted crop. At least it would be something for our animals to eat and hold our soil if a huge storm occurred. Over the years we have heard about minimum soil temps to plant any summer crops.
Let me give you a brief refresh on some accepted temperature numbers for different plants. Sunflowers will germinate at 5 degrees, maize at about 9, sorghums at 15, millets around 16–17 and legume crops like lablab around 20.
However it is never that straightforward, with any of the above selection of traditional summer crops and the temps I mentioned, is it?
By that I mean saying that all grain sorghum seeds will only germinate when the soil temperature gets to that magical figure of 15 degrees.
That is too big of an assumption or sweeping statement and it is not that specific.
Just determining how to measure your soil temps is a very casual and personal thing. With grain sorghum, maize and sunflowers we do not really want our small number of seeds per square metre planted, to sit in cold soil and be subject to disease or insects affecting them in a slower germination and emergence process.
Even just a poor or uneven strike is painful as time goes on in these crop situations.
I have written and spoke about north-facing and south-facing slopes in our countryside with the north-facing slopes being considerably warmer in this season change time.
I have witnessed on an east-west furrow basis that seeds planted on the north side of the hill or furrow emerge more quickly and evenly than the south-facing side part of the furrow.
So it’s just a matter of more sunshine, and therefore heat, units to all north facing topographic forms.
Our possible forage options mentioned above, also certainly need warmer temps to be fully committed to germinate and emerge, however we do not really care too much if we achieve a staggered germination or even a reduced germination in the case of millets and forage sorghums due to large numbers of seeds per square metre.
Lablab is fairly expensive in seed costs, so needs some more thought for success in these dry and cool times and its premier needs are good moisture in the top soil and some moist soil below this as well. Then we have the usual bogey of spring frosts, that can really make a mess of newly germinated sorghum, maize or millet plants.
In the early 2000s there was a heavy frost in mid-November and this created many crop failures or reduced yields in our spring-planted summer crops, to say nothing about frosted wheat and barley paddocks being made into hay.
No one predicted this dreadful event and I hope it does not occur ever again.