‘I’ve seen the earthworms return’ – Ernst Holl’s response to SASRI

SASRI says using lime on our high pH soils is incorrect. Can somebody then explain to me why has this soil’s pH decreased from 7,7 in 2005 to 7,2 in 2011?

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Why has the calcium increased from 57% to 71% in these six years? And at the same time why has both the magnesium and the sodium decreased?

Everything I aimed for happened exactly as predicted according to Albrecht! Excessive magnesium is the predominant cause of the high soil pH on most Pongola soils. Such soils are characterised by being very hard when dry, by having a poor water infiltration rate and water/air holding capacity.

Correct liming with calsetic lime reduces the relative amount of magnesium, while increasing that of calcium. Garry Zimmer, senior director of MidWest Bio-AG refers to calcium as the “trucker of nutrients into the plant”. What he means is that calcium plays a major role in the uptake of other nutrients by the plant.

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I have observed a major improvement in soil structure and water uptake – I personally set the pivot speeds so I can verify these facts. The soils are also now a lot softer, which is a clear indication there’s a lot more air in the soil. Without sufficient water and air, the all-important nutrient solubilising micro-organisms cannot flourish.

These micro-organisms are a vital nutrient pathway between so-called ‘insoluble’ plant nutrients and soluble nutrients taken up by the plant.

Replanting at least 10% of our cane/year is the norm in Pongola. But if my field isn’t yielding at least 95t/ha and there’s no specific reason why, I will still consider ploughing out for economic reasons. If six to eight years isn’t the current norm it soon will be using the current recommendations.

I must agree with SASRI that nitrogen application rates were excessive to start with. This was the situation when I took over the management of the estate I work for in 2001. As SASRI rightly speculated, this recommendation was made by a fertiliser company representative. My predecessor bought into it because he was desperate to stop the downward yield slide which characterises cane production in the Pongola region.

I don’t believe I’m currently losing production because my chemical nitrogen application rates are less than SASRI’s standard recommended rates. It’s my experience, and that of other biological cane farmers, that less nitrogen is required per ton of cane when soils are balanced according to the Albrecht principles. And soil life is stimulated by means such as the application of compost, compost tea and by practising green manuring and mulching.

I’ve seen the return of earthworms, which is an excellent barometer of the health of soil life. It’s a well proven fact that soil life contributes substantially to total soil nitrogen.

I take exception to the statement suggesting this is all an ‘ineffective gimmick’. There’s a wealth of evidence on biological farms in SA that proves Phalaborwa rock phosphate is highly effective in raising soil phosphorous levels and in improving cane and other crop yields. The hard facts are that Phalaborwa phosphate is cost-effective in biological farming.

It may be of interest for Farmer’s Weekly readers to know that MidWest Bio-Ag, which works with more than 5 000 farmers on biological farming practices in the US, makes extensive use of hard rock phosphate for building soil phosphorous levels. Its expert on rock phosphate rates Phalaborwa’s product as the best in the world.

I do not want to enter into an argument with SASRI as to which is wrong and which is right – I shared my perspective of what I have experienced on my farm in my article. It worked for me and for other farmers following the advice of Soiltech based on the Albrecht system.