Conservation Agriculture - The Pros and Cons

More than 80 per cent of the population depends on farming. Agriculture also makes up a significant proportion of their GDP: as much as 45 per cent in Ethiopia and 37 per cent in Malawi. (By comparison, two per cent of Canadians live on a farm and the sector accounts for eight per cent of this country’s GDP.) So the agricultural sector is critical. The foundation for real agricultural growth starts with healthy soils. The Montpellier panel, an elite group of European and African scientists commissioned to analyze development issues on the continent, published a report last December that characterizes two-thirds of Africa’s soils as degraded, along with 30 per cent of the grazing lands and 20 per cent of the forests. That degradation affects the food security of 180 million people and cuts productivity to the tune of US$68 billion annually. You don’t have to be a soil scientist to know Africa’s soils are in trouble.

"The burdens caused by Africa’s damaged soils are disproportionately carried by the continent’s resource-poor farmers," said the panel’s chairman, Sir Gordon Conway, in releasing the report No Ordinary Matter: Conserving, restoring and enhancing Africa’s soil. The Montpellier panel was critical of Africa’s continental agricultural strategy, the Comprehensive African Agriculture Development Program, and of international donors for not placing a high enough priority on soil health in their strategies to improve the continent’s food security.

"The decline in fertility exists everywhere," Sheleme Beyene, a soil scientist with Ethiopia’s Hawassa University, said in an interview. "In areas where there is a dense population, the land holding is so small that everything from that land is utilized — removed." Grazing animals are turned out after harvest to clean up anything that is left. From the road, they appear to be grazing on dust. We mine the nutrients from the soil. The assumption was that some amount would be returned to the soil through chemical fertilizer.” Beyene said. Across the continent, governments have initiated campaigns to encourage farmers to switch to improved hybrid seeds and use more fertilizer. The continental goal is to increase fertilizer use from an average of eight kilograms per hectare, which is the lowest in the world, to at least 50 kg/ha. “But chemical fertilizer will not return all the nutrients," she added.

The problem is badly degraded biological health in the soil, a declining capacity to bind and create humus, to absorb water and nutrients, and to build organic matter as evidenced by the washed-out roads, deep crevices dividing farmers’ fields, plants left dying with roots exposed after heavy rainstorms and rivers laden with rich, red silt. The Montpellier report identifies water erosion as the single biggest cause of soil loss on the continent, an irony every bit as sad as Africa’s hungry farmers. Rain, moisture so desperately needed to sustain life in this land, is simultaneously at war with its exposed and degraded soils. It pulverizes them before taking them hostage and carrying them away to the sea. All the fertilizer in the world won’t fix that.

The conservation agriculture message is, at its core, an approach which emphasizes minimal soil disturbance to prevent erosion and conserve moisture while employing strategies that support healthy soil biology. Some farmers use oxen and what is known as a "ripper," a device that slices a narrow opening for the seed, instead of a plough. While many use a combination of chemical and organic fertilizers, just as many produce some of their own fertilizer by growing nitrogen-fixing legumes, sometimes intercropped with staple cereal crops. Farmers typically farm with a hoe. They plant crops into rows and then pull those rows into ridges, like we would hill potatoes, sometimes a foot high, leaving deep gullies between rows. It’s back-breaking work. Under conservation agriculture, farmers do away with those ridges. They instead make planting basins into which they put a small amount of manure and later poke their seed in with a stick. Without the ridges, they can plant their rows closer together, which increases the ground cover, paving the way for higher yields. They use mulch made from past crop residues or composted plant material between the rows to help suppress weeds, hold in moisture and build organic matter. In this environment, higher-yielding hybrid seeds have a better chance of meeting their yield potential. The extra moisture and organic matter have resulted in a doubling of maize yields. More stable production of maize, the staple crop, means farmers can sow less of their farm to it, opening the door to better crop rotations.

Christian Thierfelder, a senior agronomist, explained how the soil changes under conservation agriculture management. "When you look at the soil, the soil (under Conservation Agriculture) is very loose, and when you get a heavy rainfall, the water can infiltrate because there is a lot of biological activity — earthworms, beetles and ants and so on that create these bio pools, like a sponge," he said. "The rainfall hits the soil surface and infiltrates, whereas on the conventional system, it just runs off or stands there." The traditionally farmed soil was hard and gravelly. "The conventional system can only make use of the water that is in the ridge and not further down in the soil," he said. Plant roots grown using conservation agriculture techniques are able to penetrate deeper into the soil and reach for added moisture. "And also, because of the residues on top, there is less evaporation of water — it just has more water available for plant growth." That’s "climate-smart" in a region where sporadic rainfalls can wreak havoc with food production.

Despite the promotional efforts of hundreds of projects offered uptake of conservation agriculture by smallholder farmers in Africa has been slow — less than five per cent in most countries. That’s given rise to a debate over whether this approach, which relies on a complex understanding of how soil, water and plants interact, is the answer to productivity issues facing resource-poor farmers who have little education and a pressing need for immediate boosts in yield. In a 2009 study titled Conservation agriculture and smallholder farming in Africa: The heretic’s view, four U.S.-based researchers challenged the notion conservation agriculture is a solution for all sub-Saharan African farmers. In their view, the empirical evidence supporting these campaigns is lacking and contradictory. As well, they argue the claims for the potential of the technology in Africa are based on the experience in the Americas, "where the effects of tillage were replaced by heavy dependence on herbicides and fertilizers."

Yet, "it is actively promoted by international research and development organizations, with such strong advocacy that critical debate is stifled," wrote study authors Ken Giller, Ernst Witter, March Corbeels and Pablo Tittonell. "Concerns include decreased yields often observed with Conservation Agriculture, increased labour requirements when herbicides are not used, an important gender shift of the labour burden to women and a lack of mulch due to poor productivity and due to the priority given to feeding of livestock with crop residues."

Research published in the journal Nature in 2014 concluded that simply eliminating tillage from these systems might actually reduce yields and increase food insecurity. "The common assumption that no-till is going to play a large role in the sustainable intensification of agriculture doesn’t necessarily hold true, according to our research findings," said Cameron Pittelkow, who co-authored the Nature study as a post-doctoral scholar at University of California-Davis. These researchers concluded the only way conservation agriculture works is when it is part of a system that also includes crop rotation and mulches that retain water, suppress weeds and improve soil quality. Those aren’t always available to resource-poor farmers. The authors also pointed out some of the promised benefits, such as increased fertility and weed suppression, take years before they become noticeable.

In January, the Journal of Sustainable Development published an article documenting high abandonment rates of conservation agriculture once NGO support is withdrawn. Some have suspected smallholder farmers who participated in the projects were only there for the free fertilizer, seed and food served on the extension days. But that article also noted persistent adoption was more prevalent among the poor, which "supports claims that Conservation Agriculture is a pro-poor technology."

Chris Woodring, a researcher and small-scale farmer from Kentucky, was assigned to interview 50 farmers across five African countries about their experiences with conservation agriculture, documenting where it is working, where it is not and identifying the challenges smallholders face in adopting the soil-saving methods. Conservation agriculture proponents believe it offers the best opportunity to stave off a looming environmental and human catastrophe in Africa. But the diversity of these farmers, their remote locations and cultural and language barriers make theirs a difficult story to tell. People don’t necessarily measure the success of their farming in yield per hectare or map out their plots with laboratory precision. Rather, it is based on whether their farm produced enough to feed the family from one crop to the next, whether their diets have become more diverse and whether there is enough money to send the kids to school or buy sugar, soap or a cellphone. Understanding the cultural context and why there is a difference between what they say and what they do can also be difficult.

It is hard to find enough of the mulch they use to cover the ground between the rows of maize, especially in the early years. During the dry season, farmers with livestock often allow their cattle to roam freely looking for forage. Landowners have no fences to keep them from eating the mulch. As well, the decaying crop residues attract mice, which brings the "mice-catchers," children who set the field on fire so they can catch the rodents as they flee. Once caught and their entrails removed, the critters are boiled and roasted until they are crispy and consumed as a delicacy. Then there is what one farmer described as the "man problem," a gender-based competition within families over resource allocation. "It is customary here that the husbands are in control of the land, so they are the ones who share a portion for them to practise Conservation Agriculture," an interpreter explained. "Most of them are not interested, because they are not seeing instant benefits, so they just give small portions to their wives, because it is mostly the wives who have adopted the technology."

"In Malawi, food production is done by women, and so you find that food becomes a gender issue. Men would prefer to grow a cash crop where women would like to look after their families. So hunger becomes the main issue for the women,’ said Sain Mskambo, a project officer with the NGO Find Your Feet, based in Mzuzu, Malawi. The tobacco industry began contracting with smallholder farmers here in the early 2000s after large commercial tobacco-producing companies went bankrupt. Farmers are provided with inputs and advance cash payments to tide them over until their crop can be sold. Local extension workers say farmers sometimes don’t get enough from their crop to pay those loans back. But they also say that when prices are good, businesses and the booze halls in the region do a booming trade when the tobacco is sold in May. Cellphones, televisions and new clothes don’t do much for food security, and many of these families still struggle to find enough food to eat during the lean months. But they do bring with them a certain status. Hunger here is often hidden behind a flashy dress shirt. It’s a conundrum for NGOs that have been championing conservation agriculture as a means of improving food security. Helping farmers sustainably produce tobacco isn’t what most donors have in mind when they send cheques to help alleviate poverty and hunger.

Woodring’s work, now completed, reveals interesting patterns. Weeds are by far the biggest challenge for these farmers. Many have started using pesticides, but with mixed results.

"When they use mulching to control weeds or hand-hoeing to control weeds, then that really limits their adoption of conservation agriculture to the amount of labour they have to put the system into practice," Woodring said.

Consistent with the North American experience, pesticides offer a less labour-intensive alternative to hand-weeding, which makes them exceedingly popular with women, who do most of the weeding. But many smallholders can’t afford to buy pesticides, and if they do, they often don’t know how to use them safely. We watched as a young woman wearing no protection measured out the insect killer cypermethrin from a bottle of concentrate into a backpack sprayer to mix. When she donned the backpack sprayer and began spraying a field of cowpeas, most of her skin was exposed. As well, how well these products work depends on rainfall. Farmers can lose their investments — and their crop. That spells hunger. "If you spray and it doesn’t rain for five days, it won’t work," said Wilfred Hamakumba, who has been practising conservation agriculture on his farm near Choma, Zambia, for 13 years.

Woodring heard repeatedly from conservation agriculture farmers that their yields increased, which has improved the quality and quantity of the family diet, as well as their income. That has positive implications for child nutrition, the family’s overall health and access to education. It is an investment that pays off in spades. "I think the potential for CA is somewhat greater than actual adoption," Woodring said Woodring, who has been monitoring the progression of reduced-tillage agriculture across Africa for the past seven years, said the issue isn’t whether conservation agriculture is the right approach, it is how best to make it happen. The more we work the soil conventionally, the worse our soils will become, the less productive they become… With conservation agriculture, your soil improves, it improves dramatically in many cases."

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