The United Nations Educational, Scientific and Cultural Organization (UNESCO) calculates that civilization’s basic water needs are 20 to 50 liters (5-13 gallons) of uncontaminated water per person, each day. This includes not only drinking and bathing water, but also water used in industry and agriculture. As examples, farmed cattle consume around 4,000 cubic meters (over one million gallons) of water per head during their lives – and cereal crops require approximately 1.5 cubic meters (400 gallons) to yield one kilogram of grain. It is well-established that agriculture consumes 70 percent of global fresh water for the irrigation of crops, and it is predicted that unsustainable water withdrawal will increase 50 percent by 2025 in developing countries, and 18 percent in developed countries. This includes the world’s irrigation needs that are expected to increase in coming decades, with irrigated area in developing countries expected to increase by 40 million hectares (20 percent) by 2030.
Understanding that the majority of water used in traditional agriculture is lost, IFDC has developed crop management systems that dramatically reduce water inefficiencies while simultaneously improving crop quality and yields.To reverse the trend of overuse, progress is being made toward broader adoption of efficient agricultural irrigation systems – while advanced techniques and tools are being employed to reduce soil evaporation, filtration away from root zones and the redirection of water use by weeds.
Conservation Through Focused Irrigation
Recognizing that world agriculture’s indiscriminate use of water is unsustainable, IFDC has focused extensively on natural resource-friendly mechanisms that promote conservation while enhancing agricultural production. Micro-irrigation and fertigation have been at the forefront of IFDC's best irrigation practices, with particular benefits to vegetable growers in the developing nations that the Center serves.
Micro-irrigation is the concentrated delivery of water to plants through a system of drip tubes positioned along crop rows. Water is supplied via a large water storage bucket that, when elevated, utilizes gravity to supply water to the drip tubes. The most common of these systems is the Chapin Bucket kit that is now used in over 150 countries. This system is extremely effective in providing maximum irrigation results while using the least amount of water. And although the system is often relatively expensive to institute, particularly for smallholders in developing countries, the increases in crop quality and yields quickly offset the initial costs.
As the name implies, fertigation is the combination of fertilizer and water delivered simultaneously to the plant. This is a highly efficient method of controlling precise water and nutrient delivery to the root-zone. The ability of this process to immediately address the issues of fertilizer efficiency and natural resource conservation makes it particularly attractive as a solution for crops cultivated in resource-poor regions around the world. Fertigation also allows more rapid growth in many crops due to increased nutrient use efficiency. As a result, crops can be brought to earlier harvest – often allowing a second harvest from the same field in the same cropping season.
Utilizing this crop management method, farmers are increasing incomes through: cost savings due to substantially reduced fertilizer waste; reduced labor requirements due to the relative automation of the process; and better crop quality and greater yields due to increased nutrient use efficiency.
Plant growth on plastic mulch is often up to twice that of plant growth on bare soil. This is due to a number of crop management efficiencies including a greenhouse effect, CO2 capture, reduced leaching, lower compaction, better weed control and the prevention of soil water evaporation. Specific plastic mulching benefits include:
- Plastic mulch creates a greenhouse effect, increasing soil temperature at a depth of 2 inches by 4-5 degrees Fahrenheit under black mulch, and 8-10 degrees Fahrenheit under clear mulch.
- Plastic mulch is nearly impervious to the penetration of carbon dioxide (CO2) gas, a critical element in photosynthesis (the process by which plants use CO2 to make sugars which are either consumed in respiration or used as the raw material to produce other organic compounds needed for plant growth and development). High levels of CO2 build up under the plastic mulch and are routed through the plant holes in the plastic, causing a “chimney effect,” or localized concentrations of CO2 that are absorbed by growing leaves.
- Soil under plastic mulch experiences reduced compaction, remaining loose, friable and well-aerated. As a result, roots have access to adequate oxygen, and microbial activity is enhanced.
- Black plastic provides excellent weed control in the covered crop row, deterring growth due to lack of light and other nutrients. Black plastic can also result in an earlier harvest (2-14 days), while clear plastic can result in a 21-day earlier harvest.
- A mulched crop is cleaner and less subject to diseases and crop rot because plastic mulch eliminates direct contact with the ground where dirt, pests, diseases and standing water can quickly contaminate growing plants or fruits.
- Water vapors that would normally escape into the atmosphere are condensed onto the underside of the plastic mulch and redistributed back to the soil.
This simple process of lifting maturing crops off the ground surface with the use of wooden stakes is remarkably effective in preventing pest interference and ground rot, yet is often overlooked as a technique in developing countries. As the plant grows, a wooden stake is inserted near the plant and the two are bound together with ties. Throughout the growth process, the ties are adjusted to ensure that the method does not interfere with the plant’s growth. Combined with other crop management tools such as drip irrigation, fertigation and/or plastic mulches, crop loss to pests, disease and rot are substantially reduced, further increasing crop yields, and subsequently, farmer incomes.
Fertigation field trials in Ghana