Precision agriculture (PA) has emerged as a promising new path to increased environmental sustainability in food production. GPS positioning is helping America’s farmers optimize yield, reduce fertilizer runoff, and save diesel fuel. Smallholder farmers in poor countries need new options as well, but they might seem poorly suited to take this same PA path. Smallholders farming one hectare or less don’t need GPS systems to know where they are in a field, and they seldom use powered machinery so auto-steering to save diesel fuel is not an issue. Since they do so much of their seeding, weeding, and harvesting by hand, they already have plenty of precision. But they often lack accurate information about the needs of their soils and crops, location by location, or an adequate means to conserve and manage water.
Precision agriculture in a slightly altered form can thus be spread to smallholders in Asia and Africa, despite farm size and asset limitations. Remember that no-till farming had its start on big farms in North America in the 1970s, initially as a way to save diesel fuel, but variants on this “conservation agriculture” approach have now been developed for small farms in the tropics. Likewise with GMOs. Beginning in the 1990s, large corn and cotton farmers in the United States began planting genetically engineered Bt seeds to protect against insects with fewer chemical sprays, but within a decade Bt cotton was also being grown profitably by small farmers in China and India. GPS positioning and variable rate machinery systems will not transfer directly to smallholders in poor countries, but there are other elements of PA—including the use of modern sensors, soil mapping, more precise irrigation systems, and mobile communications—that can be taken up at low cost and with greater ease. Consider a few promising examples:
- Chlorophyll meters (SPAD) and leaf color charts (LCC) are simple hand held tools that can be used to measure the nitrogen status of rice fields, to determine the appropriate timing for adding nitrogen. In India, LCC-based real-time nitrogen management has allowed farmers to avoid waste and reduce chemical use by 40kg per hectare, with no loss of yield. One step up are hand-held “GreenSeeker” nitrogen meters with an active light source that allows for operation under heavy clouds, at dusk, or in dusty conditions.
- Affordable moisture sensors are now being developed that will tell small farmers, via simple traffic light displays, whether moisture at three different depths in a field is adequate or inadequate. The data from these sensors can also be geo-referenced by a smart phone and displayed on Google Earth, to improve water management within multi-user irrigation schemes.
- AflaGoggles are a compact optical device being developed to detect aflatoxin contamination in maize or groundnuts in Africa. The goggles incorporate a UV fluorescence spectral-based technology, and can be used in the field by either by farmers or commodity handlers, with no advanced training required.
- Modern soil-mapping techniques can now be employed to measure nutrient deficiencies in soils, with changes in soil composition tracked through spectral imagery collected from satellites. A soil-mapping project of this kind has been underway in Ethiopia, to help that country provide fertilizer blends to farmers targeting the exact nutrient deficiencies of local soils. Blends with up to six different nutrients will be made available to cereal crop farmers on a site-specific and crop-specific basis.
- Countertop soil testing is another interesting option for Africa. Battery-powered ion sensitive electrode (ISE) devices can determine soil pH from samples, or even diagnose nutrient deficits. African farmers could bring from their fields to an extension office (or NGO office, or an agro-dealer shop) to receive tailored fertilizer recommendations.
- Laser land-leveling can work even for poor farmers because it is a one-time procedure. Small farmer cooperatives can share the equipment costs, which may be only about $10 for a day’s work. Rice and wheat farmers in India have gained an added $144 per hectare annually from laser leveling, thanks to money saved on water and energy, plus higher yields. Precise leveling can increase water use efficiency on rice by 65 percent. In Haryana, laser land-levelers are now provided to wheat farmers in combination with Zero Tillage machinery, saving labor and boosting yields because seeds can be sown at exactly the right depth.
- Drip irrigation equipment can be extended to small, low-resource farmers through contracting or through out-growing schemes, where a private company covers the installation and maintenance costs while the small farmer profits from an assured market and higher yields. In India, Jain Irrigation provides over 1600 farmers with precision drip equipment plus all inputs and services and then buys back farm produce at a pre-determined price. In Burkina Faso since 2011, farmers in ten different provinces have been purchasing their own drip irrigation kits, which allow them to grow vegetables on small 500 square meter plots all year long. Small farmers can even make their own drip irrigation systems using buckets or barrels as water reservoirs, and bamboo or PVC tubes as distribution pipes.
- Fertilizer deep placement (FDP) by hand can replace an indiscriminate spreading of urea in lowland rice production. The FDP method places urea briquettes precisely in the rice root zone, cutting fertilizer use by 40 percent and reducing runoff, while boosting rice yields 25-40 percent.
- Mobile phones are now widely available in Sub-Saharan Africa, where more than 650 million individuals are mobile phone subscribers. Phones are helping farmers in Africa manage money (mobile banking), and learn about prices in the marketplace before setting off a long journey on foot. Phones also help farmers stay in touch with extension agents and learn about the weather. Innovative cell phone apps such as iCow can now help African dairy farmers keep track of the gestation cycles of their individual animals, optimizing herd expansion.
PA also tends to be ignored by international financial institutions like the World Bank, which have long been dominated by economists rather than engineers or agronomists. As for the leading international research centers of the CGIAR, they remain heavily focused on biological innovations from traditional plant breeding. There are 15 separate international centers in the CGIAR research consortium, and they pursue 16 different research programs, yet not a single center or program is currently focused on PA, GPS, sensor systems, or ICT. There have been some precision-focused exceptions: ICRISAT developed a micro-dosing approach to fertilizer applications in Niger, and the International Wheat and Maize Research Institute (CIMMYT) is experimenting with GreenSeeker handheld crop sensors in Ethiopia.
In the foundation world, precision agriculture gets greater support. The Bill and Melinda Gates Foundation, for example, supports the Africa Soil Information Service (AfSIS) to produce timely soil health surveillance maps useful to smallholders. Bill Gates warned more than four years ago that, “a digital revolution is changing the way farming is done, but poor small farmers aren’t benefitting from it.” All agree that smallholders need to boost their income while generating less impact on the resource base. Precision agriculture has been doing that in the United States for several decades now, so variants on this low-impact, smart-farming approach should be developed for smallholders in tropical countries as well.