Combating soil erosion and increasing soil organic matter in Paraguay
The past week in Paraguay, a land-locked country nestled between Argentina, Brazil and Bolivia in the heart of South America, has been fantastic. I have been given a week’s tour of the southern part of the country by Rolf Derpsch, a 76-year-old German who speaks four languages fluently and another two well enough to hold a conversation. He is regarded as one of the pioneers of no-till in Paraguay and has been here since 1988. He has seen the country go from only cropping 5,000ha in a no-till system in 1988 to now where 97% of the land is under no-till. There are now 2.7 million hectares of no-till in Paraguay.
This is Victor Ramires. What a man: what a farmer!
Rolf had organised a tour where we visited a number of producers ranging in size from 15ha to the biggest at 17,500ha – and that’s a family farm.
The scale in places is amazing but very little is flat, with the terrain resembling the large rolling areas of Suffolk and Cambridgeshire but with the soil a reddish-coloured clay. The road network is very poor, with most being dirt roads which become almost impassable when it rains.
And boy does it rain! The annual rainfall average is 1,650mm and a few weeks ago one farm we visited received 70mm of rain in 20 minutes.
This is why no-till has been adopted and retained in Paraguay: erosion. All straw residues are chopped or spread and nothing is ever baled. This provides the soil with a mulch covering which acts as protection against the rain when it comes. It also serves to build the soil organic matter (SOM).
Roland Wolff has seen SOM rise on his farm from 1.2% in 2002 to 2.9% now. This is fantastic and shows what can be achieved given the discipline and determination to succeed.
Farmers in Paraguay now laugh at the idea of tillage, and remember times when rivers ran red with all the soil that was being eroded. Now the runoff is clear and the soils are very much better, with a continual cover of mulch/residue that both protects the soil from a heavy and prolonged downpour as well as keeping the soil cooler when the baking sun is out and damper when the weather is hot and dry. It really does make the difference between a crop and no crop in many situations.
Iguazu Falls in Paraguay, before and after no-till. (c) Rolf Derpsch
The most memorable day occurred last week when we visited the farm of Victor Ramires in the morning and Lucas Van Ryckeghem in the afternoon.
Victor was a first generation farmer who had started with only 15ha of land and a wooden shack for a house. He was one of the first “subsistence farmers” to embrace no-till in 1988 and has stuck with it ever since, perfecting the art of combi-cropping (two crops growing in the same field) and double cropping (two crops grown each year). Since then he has built a very nice brick bungalow for his family, put his three children through university, and is now building a new house for himself and his wife away from the busy road so that his daughter can move into their old one.
Then we drove into an area where we found Lucas. He emigrated from Belgium in 1982 at the age of 22. His father had bought, with the help of some foreign investors, 9,000ha of land and Lucas has spent the past 22 years managing it. He now has a fabulous farm which is roughly split between 3,000ha cropping (soya bean, cotton, maize, wheat and sorghum as a cover crop that the cattle graze) 3,000ha seeded pasture (where he runs 4,000 cattle, raised and bred on farm with 5/8 Aberdeen Angus) and 3,000ha of forest, although some of this is now being fenced and seeded so the cattle can graze amongst the trees.
The scale was impressive, and the cattle were by far the best we saw anywhere in the country.
His take home quote was “Everyone copies and no-one thinks!”
Having spent a week in Paraguay the conclusions for my Nuffield studies came down to three main things:
- Keep a residue on the ground at all times (don’t bale straw).
- Grow a diverse range of green manure cover crops wherever possible.
- Grow a diverse rotation including a brassica and a legume if possible.
According to Rolf Derpsch, my host and inspiration for the week, this will prevent any compaction occurring in no-till as well.
This would fit with my current thoughts at my home farm where we currently have a wheat, OSR, wheat (cover crop), spring beans rotation although, as we have come to realise, change is here to stay.
It’s off to Brazil now for two weeks, starting off with a meeting near Brasilia hosted by the ‘father of no-till’ in South America, John Landers.