Conditions for arable farming differ greatly between Central Europe and the tropics. Strong sunshine all year round leads to high soil temperatures: in Togo at least 28 °C, and well water from 30 m depth is 27 °C. When this warm soil is aerated by tillage, humus breaks down quickly and what remains is CO2 (more on this, in German). At midday bare soil reaches 40 °C and soil moisture evaporates fast. Water and nutrients can only be stored with enough humus.
Our terrace, surrounded by water. The tropical climate brings further problems: heavy rain of sometimes 100 mm or more a day washes dissolved fertiliser salts into deeper soil layers, and as much rainwater as possible has to be stored. A sufficient humus layer can do both. I set up a small weather station to measure rainfall more precisely.
Slash-and-burn, still common, is very bad for the humus balance. It dates from a time when tribes moved around, burned land and used it for three to four years until the soil was exhausted. In the dry season from December to February fires are often set to prepare fields or drive out the last game. There is no fire brigade, and these officially banned fires sometimes get out of control.
The photos show how maize is traditionally sown: three seeds together, usually on a ridge, with 75 cm to 1 m in between. The reason I hear most often: if one seed fails, the others will grow. A former apprentice of mine works on a large farm in the south of the Democratic Republic of the Congo, some 2,500 km away, and the same tradition exists there. The drawbacks: competition keeps the maize from developing well, poor spacing leaves room for weeds that consume the scarce nutrients, and ridges make water shortage worse because rain runs off while heavy aeration breaks down the humus.
No-till sowing into a green manure crop. The answer to all these difficulties is no-till farming, practised successfully in Brazil for more than 50 years. Two harvests a year are standard there and possible in Togo with the same climate (information at rolf-derpsch.com). Switching to no-till and not burning the vegetation alone raises yields by 50 %, partly because covered soil evaporates about 45 % less water. My wife Anita and I learned this in April 2024 at the Centre for No Till training farm in Ghana. Its head, Dr Kofi Boa, saw his mother's cocoa plantation destroyed by a fire that got out of control when he was twelve. He vowed to do something about it, studied agriculture and is now supported by the Howard G. Buffett Foundation.
Anita in the trial field. On the farm in Ghana we saw various beans and other legumes. Legumes use nitrogen from the air (78 % of the air we breathe is nitrogen) and store it in the soil, and nitrogen is one of the most important plant nutrients. They can be grown as a cover crop or sown between the maize rows about ten days after the maize, where they supply it with nitrogen. Soy is a legume too and often precedes maize in Brazil.
Seed of various legumes and other plants grown and tested on the farm in Ghana. New ones are tried all the time, including plants that make soil phosphate available, another key nutrient besides potassium.
No-till sowing into soil covered with plant residues. My aim is to lease 1 to 2 ha of land and show Togolese farmers no-till cultivation there. I know from experience how hard it is to move farmers away from their traditions. But if I show them a way out of this toil and out of poverty, it will convince them. Then they would no longer have to sell their harvest immediately out of need but could store part of it. Around 70 % of the population work in agriculture, so the potential is enormous. What is still missing is a no-till drill like the one we saw in Ghana, and unfortunately we still lack the donations for it. That is the only reason I am in Togo: to help people!