Ways to protect your soil
Soil profile important issue
.THE photo says a lot doesn’t it?
We do love our stubble for a host of positive reasons like water infiltration, raindrop impact reduction, and erosion control by wind or water to name a few.
We all appreciate our heavier soils as we call them, as they have a higher clay content and this allows them to hold a larger amount of plant available water capacity than a loamy or sand type soil. However these heavy soils have much slower rainfall infiltration rates and this can be a real issue in storm season, here in the north. Sure, if you have big cracks in the soil, from this shrink/swell attribute, they will dramatically assist in filling the soil profile from the bottom up, however this is not always the case with cracking clays. With some crops like our pulse crops not producing much stubble, it is not uncommon to see paddocks that have little to no stubble and are as bare and as hard as a billiard table. Of course any medium to heavy rain on these blocks is going to run straight off, taking a lot of soil with it down the creeks and gullies of our property. We just cannot afford to let this happen as it takes many thousands of years to replace that soil loss.
Heavy stubble loads with conventional planting equipment years ago, was fire burned prior to planting. These days, stubble is severely held onto by many of us, despite disease issues like winter cereal crown rots impacting on future winter cereal crops and increasing herbicide resistance issues.
Large rainfall events can lead to run-off of course, but they have this ability to possibly infiltrate deeper into the soil profile and therefore add positively to our stored soil water levels for the next crop.
Getting the rainfall moisture deeper in the profile can protect it from following evaporation losses over the next few weeks. How about those 10mm rain events or even 20mm? We often curse them as they bring up weeds
in a fallow or even crop situation, but do not add much to the profile of soil water, especially in summer. In winter crops however, it can be a different story as many cereal grain crops have just used their leaf structure to funnel down these small falls of rain to the root zone at the base of the plant, for secondary root development to occur.
A huge benefit and a lifesaver to many wheat and barley crops over the years.
So where does this leave us all now? For my mind, many paddock situations are different and all information needs to be taken into context for many agronomic advice or decisions that need to be made.
The one thing we are mostly short of is moisture and the last 14 months have highlighted that again. So my main focus is still directed at encouraging our rainfall events to be effective and efficient and to reduce as
much as possible the future evaporation. Then you have to also integrate weed control with knock-down or residual herbicides, nutrition requirements and your own planting capabilities for the next crop.
Nothing very new here is there? However it is good to refresh ourselves on the huge benefits of stubble and the one major ingredient we are invariably short of and that is soil moisture and effective rainfall events.