Soils are indeed at the core of any crop production system. Without a healthy soil, crops cannot thrive. While measuring the effect of soil erosion at national and global scales is near impossible, all farmers see the difference when effective soil conservation techniques are in place.
Putting the right strategies in place to control erosion is becoming increasingly urgent as climate change is leading to rains falling more erratic and intense than before.
From the gentle rolling lands in Burkina Faso to the steep hills in northern Vietnam, I have seen the devastating effects of rainfall on poorly managed soils. On gentle slopes of even as small as five degrees, the torrential rains wash away the top soil and seal the top layer, after which no more water can penetrate the soil. To remedy this, farmers in Burkina Faso learned about making contour bunds (raised ridges every 20 meters across the field) to allow the rainwater to infiltrate. On steeper slopes, where the land is much more difficult to be ploughed by anaimals or machines, vegetation barriers or terraces are possible solutions to stop soils eroding.
Depending on the slope, type of soil, availability of labour and other resources a wide range of options are available to improve soil and water management. Networks such as WOCAT (the World Overview of Conservation Approaches and Technologies) support organisations working on the ground with farmers by making hundreds of sustainable soil and water management technologies available in an authoritative website.
While many development agencies and projects believe that encouraging smallholder farmers to use mineral fertilizers is the quickest way to solve low crop productivity, without proper soil conservation techniques farmers will see most of their money invested wash down the drain.
And many more under Sustainable Land Management
The WOCAT SLM database: https://qcat.wocat.net/en/wocat/
People usually have a good reason for ignoring free advice.
So when Tumpale Pindani, my Malawian colleague, asked me â€śHow long will it take before the people in Malawi accept conservation agriculture,â€ť I could tell that it had already been a long slog, even though I couldnâ€™t answer her question. After all, conservation agriculture has worthy aims, such as improving soil fertility and halting erosion. Conservation agriculture includes many practices, such as minimum tillage, cover crops, and straw mulch. Most of these are old practices, widely used somewhere in the world, although none are used on farms worldwide. Some farmers have competing goals, besides soil conservation.
Tumpale and I were visiting a field in Malingunde, in Central Malawi where Alefa had harvested groundnuts and was about to plant maize. So Alefa was rotating crops, which is one component of conservation agriculture. Alefa asked us how she could improve soil fertility, and Tumpale recommended composted manure, another component. Alefa listened with interest.
On the way back to the car Tumpale stopped and asked me to look at a boy sitting on the ground in a dry field. Most of the ground was bare, except for some spots where the few remaining maize stalks had been piled up, ready to burn. â€śDo you know what he is doing?â€ť Tumpale asked.
â€śHeâ€™s waiting for rats,â€ť Tumpale explained.
The dry season is driest right at the end. And that is when older children look for rat holes. The kids pile up maize stalks where the rats like to hide, and burn the stalks, creating a clear, wide open field of bare earth and ash. There is nowhere for a rodent to hide.
Then the boys dig up the rat holes, and when the rats run out, the boys club them with the hoe, and take their prey home to eat.
Itâ€™s not as terrible as it sounds. Iâ€™ve had rat three times this year so far, twice in Uganda and once in Nigeria. Rat is a treat, especially if grilled on an open fire.
One conservation agriculture practice is to leave crop stubble in the field, where it slowly decomposes, protecting and enriching the soil. Itâ€™s a sensible recommendation. But people arenâ€™t following this suggestion, at least not in Malingunde. During the scorching dry season there is not much else for cattle to eat, so after harvesting the maize, people take the corn stalks home, and feed the leaves to their animals. Women burn the bare stalks as fuel, for cooking. In this part of Malawi crop residues are more valuable at home than in the field.
Stalks that are not gleaned during the dry season may eventually be burned to clear the ground for gourmet rat hunting. Conservation agriculture is marketed as a package, or a brand, but that doesnâ€™t mean that all recommended practices will be adopted. Some will have to take second place to existing needs, like the search for tasty rats.
In the 1980s desertification was a cause for alarm. The basic idea was that smallholders in the Sahel were grazing too many animals and cutting down too many trees. As a result, the Sahara was creeping into the Sahel, turning fields and pastures into desert. The reality turned out to be more complex than that.
By the 1990s, academics had debunked the idea that peasants caused desertification. In Gourma, Mali for example, there was no relationship between deforestation and domestic firewood consumption, because smallholders gathered deadwood as fuel, and did not down cut live trees (Benjaminsen 1993). In fact, the boundary line between the desert and the Sahel had not changed in the 16 years between 1986 and 1998. Rather, the boundary ebbed and flowed with changes in annual rainfall (Nicholson et al. 1998). The number of individual trees in West Africa did decline in the second half of the twentieth century, but this was largely because of the droughts of the 1970s and 1980s.
Remarkably, smallholder farmers in the Sahel were actually encouraging the natural regeneration of trees. In a hiking survey of 135 villages in Senegal, Patrick Gonzalez noted that when a tree sprouted, people would protect it, and when it was large enough prune it (Gonzalez 2001). This may strike some readers as wishful thinking, but William Critchley and colleagues at the University of Amsterdam have also documented farmers in the Sahel protecting small trees. Critchley et al. have made several videos on how farmers in the Sahel use various simple techniques to encourage trees. Farmers dig small pits that collect rain runoff. By applying manure in these pits the soil is improved and when a tree seedling germinates, farmers keep livestock from nibbling it away.
As an added bonus, many of the trees that seemed to have died in the 1970s and 1980s still had life left in the roots. As the branches began to grow back from these â€śunderground forestsâ€ť farmers protected them as well.
In his video Managed regeneration, Critchley uses aerial photos of the village of Galma, Niger to show that dramatic recovery of vegetation between 1975 and 2002.
During the drought decades, international projects funded nurseries of eucalyptus and other exotic trees in the Sahel, but most of these died (Gonzalez 2001). One might be forgiven for assuming that foreign trees are simply inferior to native species, but itâ€™s not quite that simple. Eric Boa points out that in the Sahel the single most important tree across the transition zone from arid to semi-arid is not actually a native species, but the leafy neem, a native of South Asia which was introduced to Africa about 100 years ago.
Neem now grows from Mali to Sudan. Neem trees are fairly drought-tolerant, but even they declined in the early 1990s, probably because of the long dry spell. Some activists prefer indigenous species, such as Balanites aegyptiaca, but neem grows much faster, which is why people like it (E. Boa, email). In the past few years I have been impressed by the sight of great neem trees around farmsteads in Mali.
Rural people know as well as anyone that trees provide fuel, timber, shade for livestock, fruit and other services. No doubt future generations in the Sahel will encourage native trees, and continue to plant naturalized foreigners like neem, adapting to the slow rhythms of moister and dryer decades.
Benjaminsen, Tor A. 1993 Fuelwood and Desertification: Sahel Orthodoxiesâ€™ Discussed on the Basis of Field Data from the Gourma Region in Mali. Geoforum 24(4): 397-409.
Gonzalez, Patrick 2001 Desertification and a Shift of Forest Species in the West African Sahel. Climate Research 17:217â€“228.
I was home Thursday evening, when my daughter, Clara, called us outside to see the forest fire. It was dusk and there was a bright, orange patch of flame dancing around the crest of the Andes, above Cochabamba. The jets of flame were so large we could see them leaping high above the tree tops, even from the city, far below on the valley floor. There had been no rain lately, so we imagined that within a few days the whole forest would be burning.
Now here, the word â€śforestâ€ť needs some explanation. This forest is a large swathe of pine and eucalyptus planted on the upper slopes of the Andes in Tunari National Park. Until the twentieth century, the mountain had been covered in native trees: short, gnarled, slow-growing hardwood trees with papery bark, called qhewiĂ±a in Quechua (Polylepis spp.). Throughout the mid twentieth century, wagon loads of the qhewiĂ±a wood were sold as firewood in the city of Cochabamba.
By the 1980s, these native trees were mostly gone. Then the Swiss government financed a project to reforest the mountain. Over the next few years, they planted pines and eucalyptus in the national park on the mountain above the city of Cochabamba, and in and around farm communities in the central departments of Cochabamba and Chuquisaca.
By Friday the fire we had seen from our home was largely out. On Sunday our curiosity got the better of us and with some of the extended family we drove 10 km above the city on a winding, dirt road, and parked at an abandoned pic-nic ground. Looking around, I realized that the Swiss planned Tunari National Park to be a peri-urban, family-friendly recreational park, where people would come for hikes and meetings in the pines. Among the trees above the city, the project left behind some childrenâ€™s playgrounds and brick cabins where people could hold meetings or training courses. The buildings were abandoned years ago. The roofs have started to cave in and someone has stolen all of the rope from the childrenâ€™s swings.
We hiked towards the site of the fire. There were isolated patches of smoldering fire, but no flames. A police fire-truck passed us on the way down, heading for the city. The fire fighters had also decided that the flames were out.
Once in the forest, we could see that the dried grass was thick on the ground, and that seems to have been the main source of fuel for the fire. We thought that some of the trees might survive. This forest has a fire almost every year, during the dry season, and many of the big pines and eucalyptuses have survived earlier burns.
We stopped at a ranger station to get more information. The staff explained that Tunari National Park has seven employees, and they respond as soon as they see a fire. When the fire is too much for the park staff to handle, they call on the departmental branch of the national police (the fire truck we had seen). The park service also relies on an energetic group of volunteers, a membership-based community organization called SAR (Search and Rescue) that looks for lost hikers and operates an ambulance, besides helping to put out forest fires. SAR was founded in 1988 and has no ties to the Swiss project that planted the forest.
By 1999, the original Swiss reforestation project morphed into another project, and no more trees were planted. Yet the original planted forests were not abandoned. The patchwork of organizations (the national park, the police and SAR) that come to the rescue are doing a competent job of saving the trees. The planted trees are now thick and healthy in most places.
The Bolivians put out the forest fires, but donâ€™t care much for the cabins and other buildings left in the forest. I think that is a pattern; when donors invest in tangible, capital goods, local people tend to maintain certain kinds of investments (especially forests), even if the local people are not always willing to maintain buildings and some other investments.
Forests are rich grounds for hunters. Some of the greatest riches from hunting, however, lie underground, if you know where and how to look.
Truffle hunting is a hidden world in more ways than one. Across Europe there is no great secret to the types of forests where these edible fungi might occur naturally. But this is only the beginning of the search. The most successful truffle hunters have an intimate understanding of soils, trees and the landscapes which favour truffle growth. They also have a well-trained dog.
I recently went on a truffle hunt in north east Italy with Enrico and Ape (pronounced ‘appy’), his truffle dog. We left early in the morning. Ape sensed she was going on a hunting trip as Enrico walked across the garden to release her from the wire compound. She bounded towards the car and the open boot. One leap and she was in her cage, ready to sniff out truffles.
Ape is a Brittany spaniel, a breed normally associated with bird hunting. She has been trained by Enrico to sniff out the odours associated with the best truffle species. Enrico keeps a close eye on where she goes, and, after a successful discovery, gives her a reward of biscuits. Sometimes her hunting instincts kick in and sheâ€™s sharply reminded by Enrico to ignore distracting smells and concentrate on truffles.
Enrico drives past the first potential truffle site, a nearby village to where he lives. â€śThere is a truffle hunter who lives here and the rule is that we do not invade other peopleâ€™s collecting areas.â€ť Truffle collectors carefully guard their hard-won knowledge of good places to hunt. Some areas are well known. It is difficult to conceal a parked car on narrow country roads. Enrico tells me that some of the older collectors are opening up about their favourite sites, aware that priceless local knowledge might be lost.
Truffle dogs are valuable, reflecting the riches the hunter might reap. You can buy dogs already trained, with one website quoting $12,500 in the USA (where truffles are also hunted), but in north east Italy â‚¬1000 is a more reasonable price. As with so much of the truffle business, it is not clear how many dogs are traded. I suspect most people train their own.
As to the fabled riches that lie underground, 2015 has been a hugely disappointing year. Prolonged drought early in the year stymied the growth of primordia, the young fungus-roots on which the truffles will eventually mature a few months later. I was surprised to learn that in this region several truffle species are produced throughout the year, though the highest quality white truffles, the most valuable of all, occur later in the year.
Prices vary hugely, depending on season, species and who you sell to. In north east Italy, white truffles might costÂ â‚¬1000 â€“ 2800 per kg for the final consumer, more for the exceptional, outsize specimens that catch the newspaper headlines. Black truffles are the next most valuable species, around â‚¬600 per kg, also retail. Hunters receive about half the retail price. Enrico stresses these are only guideline figures, masked by the informalÂ trade in truffles and the dominance of a few major buyers. I ask Enrico to estimate the total value of the truffle market across Italy in a year. â€śAround â‚¬50 million,â€ť he reckons, â€śthe amount the hunters receive. The added value is much higher, about â‚¬200 million.â€ť
Truffle collectors have to sit an exam each year, with 60 multiple choice questions aimed at testingÂ their knowledge of how to collect (no rakes) and so safeguard future harvests. Collectors must know about land rights and respect other forest users. Enrico always carries his license, though heâ€™s never had to show it to the forest rangers. There are over 70 000 official truffle collectors in Italy. The exam and license system might suggest a close regulation of the truffle trade, but much remains unknown about how it operates.
The truffle business in Italy is self-organizing and self-sustaining, and by all accounts it works well. Yet a lack of transparency creates doubts about the fairness of transactions and weak data undermines confidence in the the sustainability of collecting from the wild. Enrico was contacted several times during my short stay by fellow truffle hunters. Mobile phones help to share useful information and swap experiences for mutual benefit. But networks of hunters tend to be local while buyers operate on a larger scale, and some information is too valuable to an individual hunter to share with others.
Researchers need to respect local knowledge and handle their natural curiosity with care. Not all information needs to be shared, and knowledge may at times be most valuable when it is kept in the minds of those who possess it.
There are few obvious weaknesses in the current system of light regulation and the strong code of conduct amongst professional hunters. Making local knowledge public would undermine the existing trade. Yet there are other ways in which research can support the truffle business. Greater openness on trade, for example, would provide clearerÂ evidence of sustainable yields, and give the truffle hunters a stronger position in getting the best prices for their underground riches.