Difficult clays, roots and traffic chaos

After Brazil it was off to Buenos Aires, fortunately no “seat of your pants” connections this time as I made the transfer from Passo Fundo via Sao Paulo. The scale of this city is quite staggering when traveling by air as it appears to go on for miles.  One thing I can safely confirm is driving through Buenos Aires at night is not the most enjoyable experience: it’s busy, there are cars everywhere, undertaking, overtaking, anything goes; and doing a U-turn to a chorus of car horns summed up the foreigner abroad experience!

I visited some farms in the Entre Rios region to begin with, some 230 kilometres north of Buenos Aires, where I came across what I discovered to be some very difficult clay soils. It was easy to see how difficult they were as they resembled some of what I had back home, concrete when dry and then slippery when wet.

Entre _Rios _soils

Above: An example of the clay soils in the Entre Rios region

I met a couple of growers who expressed how small their drilling window was before it turned too wet – it was days rather than weeks. Moisture retention aside, they both said it would be impossible to achieve decent crop establishment without no-tillage and it was easy to see why 90% of farms in Argentina have adopted no-till.

I thought we at home could experience some wet weather, but 320 mms of rain in January takes some beating and this is what Mauricio Davidovic had experienced on the 4,500 hectare farm he managed in this region, just a small part of the 100,000 hectares he was responsible for across the world in various different continents!!  Astonishingly all the farm operations were contracted out to a number of carefully selected high quality contractors. Mauricio was meticulous in his selection criteria and choice of contractor, but safe in the knowledge that he would get excellent service with the best machines to maximise the short windows of opportunity.

The following day I went to visit Edmundo (Eddie) Nolan, who had excellent English and gave me a different perspective on the value of different types of rooting crops within a rotation.

Eddie _Nolan

Above: Eddie Nolan talking us through his thoughts on rotations

Eddie was responsible for a 10,000 hectare unit, all under no-tillage and the key to making it a success, surprise surprise, was the crop rotation!  After 12 years of no-till there was greater yield stability and he was also finding better fertiliser efficiency the further down the line he got as well.  Again water infiltration was better (sounds familiar!) and when there was heavy rainfall, water was absorbed rather than running off.

Naturally, organic matter and crop residues came up, but he put a different slant on the topic of root systems in alleviating compaction and opening up the soil pore spaces.  He advocated not only having different crops in the rotation, but alternating different root systems within the rotation, or to certainly think closely about what the crop roots are doing.  For water infiltration, fibrous roots that develop horizontally are vitally important, but wheat and corn roots tend to develop vertically, opening up the lower parts of the soil and wheat appears to benefit the capillary action of the soil for water storage.  Certainly when you take a step back and think about the different root systems for crops, having a rotation with a single type of root system would certainly not be as advantageous as a rotation containing vertical and horizontal root systems.  It was a bit of a light bulb moment that it is not only the variety of root systems of cover crops that is important, but also the cash crops within the rotation have a vital part to play as well.

I definitely covered some kilometres in my first few days in Argentina and came across some very difficult clay soils that confirmed that no-tillage can be achieved on difficult soils with a positive mind-set and approach.

Next time:  The last part of my South American blogs.



Russell McKenzie farms 750ha on predominantly heavy clay on the border between Cambridgeshire, Bedfordshire and Northamptonshire. He grows seed on contract as well as soft and feed wheat, and his usual rotation is wheat, OSR and spring beans. A Nuffield Scholar, Russ has been researching direct drilling in extreme weather in 2013 and 2014.