BUILDING SOIL STRUCTURE

Insight

BUILDING SOIL STRUCTURE

There needs to be roots in the soil to build good structure.

By JOHN RYAN AM (The third and final story in a series) THE TRUISM of farming is flexibility. But I would add … and building soil structure. Knowing plant roots are your best friend can keep you alert to opportunities. For example, planting legumes that are deep-rooted and nitrogen-fixing. Like spring or summer rain and assessing the worth of an opportunity crop to outcompete weeds and build the soil.

This would be in contrast to a traditional summer “rip” after a thunderstorm. Deep tillage on its own is not the answer. There needs to be roots in the soil and in many cases, without the presence of roots to keep the soil open, you can find soil collapsing back into an even harder state. This is particularly true of cracking clays which can swell with moisture present and seal hard. Roots provide the important pathways for moisture infiltration. While there is no set template for building soil structure, your best starting point is with a shovel or preferably a backhoe to dig a soil pit. Take samples for laboratory testing and discover what you’re shooting at. It’s important to know your soils when, for example, you’re looking at bringing back sheep into the farm equation.

A good first step would be to deep till in spring after rain while sowing a pasture crop, preferably a variety with a deep tap root, such as lucerne. Oats also helps to prevent weeds by competition and the oats straw makes good organic matter. Also have in mind that a spring renovation of paddocks using the DBS can be very beneficial, particularly using Pro-DF points which are easier to pull soil better, in all soil types. Forming soil compaction from livestock trafficking can be easily broken, promoting soil aeration and moisture penetration. I’m also reminded of work done by Quairading farmer and DBS owner Darryl Richards.

Combined with the DBS action of deeper working to aerate the soil, treatments of lime sand, gypsum and dolomite, where appropriate, Darryl has promoted a healthier soil. This better structured soil has put him in a position of having a handle on a more balanced approach to fertiliser application with pH readings from 4.7 to 8.0 on his mainly medium to heavy country.

The soil structure on his property is slowly improving and he is starting to see earthworms. Interestingly, since he bought his first DBS 17 years ago, Darryl’s seeding rate for wheat has been 50kg/ha. He cut back from 80kg/ha, which was to help control weeds, but now with the way he manages his paddocks to have them clean at seeding, he knows every seed planted by the DBS will come up and compete with any weeds, which gives him confidence of sowing at 50kg/ha. He has even tried sowing barley at 27kg/ha and it yielded the same as crops he sowed with 40 and 45kg/ha rates. Building soil does take time but the ripple effect of profitable gains is compelling.

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