Water-smart technology for climate resilience

Farmers who live in drought-stricken areas benefit substantially from the water efficiency aspects of micro-irrigation technology (MIT). MIT is widely referred to as a climate-smart agriculture technology by both researchers and the private sector, and is linked to poverty alleviation.

MIT’s environmental impacts occur at three scales: farm level, landscape level, and climate level.

• The farm level refers to any ecological impacts on an individual farm.
• The landscape level refers to any ecological impacts in a set of communities or a watershed; effective resource management at this scale can be referred to as ‘climate-smart landscapes.’
• The climate level refers to any ecological impacts that reduce greenhouse gas emissions.

Farm level impacts

• Decreased water use: sustains well water
• Decreased salinization in groundwater: improves soil health
• Decreased fertilizer: improves soil health
• Decreased topsoil disturbance: reduces soil erosion
• Decreased pesticides: reduces die-off of beneficial insects
• Increased productivity: increases efficiency in the farm
• Increased plot size: decreases desertification by converting previously uncultivable land to arable land
• Integrated farms due to increased animal husbandry: improves soil health
• Decreased risk of freezing: the application of water droplets can reduce the stress on crops caused by a sharp decrease in temperature

Landscape level impacts

• Decreased water use: sustains regional ground water supplies
• Decreased fertilizer: reduces harmful runoff into watersheds
• Decreased pesticides: reduces harmful runoff into watersheds
• Decreased soil erosion: prevents loss of nutrient rich topsoil and increases soil water retention
• Increased MIT production of grass for fodder: alleviates over grazing pressure that can lead to desertification

Climate level impacts

• Decreased electricity and diesel used to pump water: reduces greenhouse gas emissions
• Increased per annum crop cycles: creates contiguous green space that absorbs greenhouse gases

MIT’s enclosed system limits evaporation and salinization.

Foremost, MIT reduces water usage by 30-40 percent over furrow irrigation by delivering water directly to the crop root zone; furrow irrigation results in high amounts of evapotranspiration in which water and nutrients are lost from irrigation beds and plant leaves are directly exposed to the sun. Evaporation causes the soil to dry out and decreases water-retention. Depending on the soil type, evaporation can cause laterization in exposed soil, where the soil becomes hard, cracked, and non-productive, which hinders water infiltration, the emergence of seedlings, and leads to increased runoff; laterization has been documented throughout South Central Vietnam and the desert regions of north-central Africa. High amounts of water loss put a large stress on the entire community’s water supply. Farm-level water reductions enable landscape level effects, where communities can collectively use water more efficiently.

Salinization occurs at the farm level, but affects the entire watershed, causing large underground aquifers to become highly saline. Each well a farmer uses pulls from this collective underwater source; salinization can cause significant yield reductions across the landscape.

MIT prevents water loss and soil degradation.

Farmers have reported increasing the area under irrigation due to MIT’s water and labor efficiency. In some cases, since evaporation rates are higher on directly sun-exposed soil, decreases in fallow land (i.e., increased crop coverage) prevent water loss and soil degradation. From iDE’s standpoint as an organization that strives to increase farmer income, we acknowledge that increased farm size should be balanced with the need for greater attention to the whole agro-ecological system.

With MIT, sloping land can be used for cropping. Contiguous farm crop cover results in a landscape’s ability to absorb greenhouse gases. Reduced and precision water application avoids water flowing through the plot and washing away nutrients, fertilizers, and topsoil.

Additionally, more crop cover results in less wind erosion from sandy exposed soils. Wind erosion removes nutrient rich topsoil, which reduces yield and causes more fertilizer to be applied. In windswept areas, it is difficult to replace this lost topsoil. Efforts to increase year-round crop cover at the community level have been part of a climate smart territory approach to sustainable agriculture.

MIT can reduce pesticide use and chemical runoff.

Through fertigation and Fertilizer Deep Placement (FDP), MIT users can directly apply fertilizer to the crop root zone. Many farmers also report reduced pesticide use. Decreases in pesticide use lead to potential returns of crop-beneficial insects (i.e., pollinators and predatory insects). Because MIT is more direct in its application, rather than spread throughout the field, fewer weeds grow, which reduces farmers’ need to apply herbicides. This more precise use of agricultural inputs, combined with reduced water runoff, decreases the amount of chemical run-off into the surrounding landscape. Chemical runoff can result in biodiversity loss that is critical for ecosystem function, as well as water contamination that is hazardous to human health.

MIT significantly increases yield per hectare.

Increased yields have clear economic benefits to farmers, which mitigates their climatic vulnerability to erratic rainfall and occasional failed crops. But, yield increases feed into a growing climate-smart agriculture debate. Land sparing refers to when farmers can sustainably increase their yield per hectare, which decreases the amount of total farmland needed to feed a growing population. In this frame, decreased farm land can result in increased wild lands and greater biodiversity conservation.

Animal husbandry improves soil health and reduces stress on surrounding environment.

Many farmers reported increasing animal husbandry due to the income gained and labor saved from MIT. For example, iDE observed that farmers typically allowed their animals to graze in their orchards. Animals defecated as they ate and in turn improved the health of the soil. Additionally, farmers were using MIT to grow grass for fodder. For example, overgrazing in South Central Vietnam has led to desertification from increased soil exposure. Integrated farms provide better farm level soil management and less stress on the surrounding environment.

MIT reduces energy use by 30 percent.

MIT reduces energy use from decreased irrigation times by 30 percent. Reducing energy use directly results in reducing greenhouse gas emissions. While pumps were commonly electric and only occasionally diesel in the project area, typical energy sources include coal as well as hydropower and thermal. Although difficult to calculate the exact energy savings, the amount of carbon reduction likely remains substantial.