Protect precious top soils
.THERE is rain predicted again this week and we are hoping the forecast is correct and that falls of more than 100mm occur. Some of this predicted rain, or any rainfall event for that matter, in our summers can come down very swiftly and cause umpteen problems like erosion and lack of soil infiltration.
The attached photo is from a couple of years ago and shows good anchored winter cereal stubble and a well spread chaff part too. It looks like a virtual blanket on the soil surface and this has many benefits to moisture retention and infiltration capacity. The weeds seem to love it as well.
However as we all know, our growing seasons have not been conducive to having plenty of cereal stubble on our farming country. In fact, many paddocks I have seen are devoid of surface stubble or organic matter due to lack of cropping or a rotational prevalence of a pulse crops.
As you know, one of my roles in the northern region is for Pulse Australia and providing the stewardship of growing our usual profitable pulse crops such as chickpeas, faba beans and mungbeans. However, none of these crops are renowned for leaving much stubble after harvest, so have been grown mostly lately, as a most profitable crop option by farmers.
With some indecisive marketing signals at this stage by some pulse customers overseas this year, this may be the season to swing back to cereal grains. I know it may sound a little strange for a pulse person to indicate that a cereal grain crop may be a better option for this winter of 2019.
Yet it is not only the end returns I consider in our farming systems, it is also employing good agronomic practices in our crop sequencing plans. If a crop like chickpeas suits in well after a 2018/19 grain sorghum crop, then that makes some sense. Many will need an extra big fall of rain like we had in the 2015 autumn to provide these good levels of subsoil moisture that our chickpea plants like growing into and also ensure adequate nutrition in this double crop situation.
Much of my present considerations are for the post-harvest stubble residues left behind. We have all seen enough overland water flows from big rain events and to add to that, some wind erosion on lighter soils is really reducing our quality top soil levels. Wheat and barley are the kings of stubble, with millets and then grain sorghum just behind that, for our annual crop choices in desired stubble retention levels.
So consider your cropping options and protect your precious top soil, as it takes Mother Nature thousands of years to replace what can be lost in a single summer.