By New Mexico Soil Health Champion Jan-Willem Jansens, Ecotone Landscape Planning, LLC
Dusting off a forgotten topic
Soil loss from wind is an often-overlooked effect of our way of life and the climate crisis in the arid Southwest. It is underreported and routinely underestimated but soil loss from wind is many times greater than the soil lost due to water erosion. NRCS data for 2017 indicate that the annual mean soil loss on cropland in New Mexico from wind erosion was more than 22 tons per acre while soil loss caused by water was less than 0.6 tons per acre1. A similar discrepancy applies to rangeland. The data show that these differences are not recent; they have occurred for at least 40 years. Thanks to an uptick of conservation measures and the conversion of cropland to urban development and irrigated pasture, wind erosion rates gradually declined after 2012. Yet, due to hotter weather and a subsequent decrease of plant cover, soil loss by wind could be expected to rise again over the next decade if conservation measures don’t keep pace with the worsening circumstances.
Wind erosion removes clay, silt, and organic particles from the topsoil, leaving coarser particles behind2. The fine particles, however, play a key role in the soil’s water storage capacity and in soil aggregate structure. When fine soil particles are lost soil health rapidly declines, plant productivity drops, and water erosion increases. Fine sand blown across the surface scours plants, further depleting plant productivity. Dust and fine sand also become air borne leading to reduced visibility and increased car accident risk, respiratory diseases in humans and animals, and warming of the air. Aeolian sediments foul equipment, fill irrigation ditches, increase water turbidity, and smother young plants, adding to the desertification of our landscape. Area specific amounts and societal costs of wind erosion are poorly researched but are worth our attention and mitigation. Because soil health improvement after wind erosion takes many years and costly resources, the need to act is urgent.
Fortunately, many land conservation practices exist that can be mobilized and innovated to address wind impacts on our Southwestern landscapes. Agricultural practices have often led to the application of one or a few practices at a time. Yet, this is not sufficient, as the nature and magnitude of the problem call for an integrated approach at a landscape scale.
Wind impact solutions need to be innovative in that they apply to soil health, plant productivity, and sheltering of susceptible assets and communities at a scale beyond a field, farm, or ranch. Similar to the integrated and multi-jurisdictional approaches to watershed management and wildfire adaptation, we must envision wind management as part of collaborative or community-based initiatives that create resilient and productive landscapes.
Integrated, comprehensive approaches would need to include practices that address all soil health principles. Such practices may be keyline design and cultivation, agroforestry, silvopatoralism, and landscape-scale woodland management. These practices have the shared benefits of helping to enhance the spreading, infiltration, and storage of water in the soil, generating maximum soil cover from perennial vegetation, and lifting the wind profile above the vegetation canopy over a large area.
Keyline design aims to spread water across a watershed area so that drier places receive more water, while integrating roads, tree alignments, water reservoirs, and buildings for optimal land productivity. Keyline cultivation is a subsoiling practice which allows water to infiltrate and plant roots to develop more rapidly and deeply, and thus stimulates plant growth. The application of keyline design and cultivation for wind management is beginning to catch on in New Mexico. In the past few years, many hundreds of acres of source areas of dust that frequently limit visibility on certain stretches of interstate highways have been “keylined” and keyline treatments have also taken place on private and public rangelands.
Applications of agroforestry, the deliberate and mutually beneficial combination of tree canopy cover and understory crops, in wind management have been limited to shelterbelt windbreaks in irrigated areas and small-scale projects of tree intercropping or hedgerow plantings. Outside the US, however, agroforestry in Kenya and other African countries as well as in Latin America is well developed and can serve as models for its development in the Southwest.
Silvopastoralism, the intentional combination of livestock grazing beneath a tree canopy, is traditionally practiced in New Mexico, but not with the express purpose of soil health conservation or wind management. Many cottonwood groves along rivers, piñon-juniper woodlands, ponderosa pine stands, and even high elevation spruce-fir forests were and still are being grazed by livestock. It requires managed grazing and deliberate forest stand management to optimize this practice and achieve permanent soil enhancement and control of wind impacts.
Woodland and forest management practices in New Mexico are seldom geared towards minimizing wind impacts on soil and vegetation beyond prescriptions to avoid tree blowdown. However, practical experience combined with some recent research findings could assist in designing woodland and forest treatments that keep the wind profile above the canopies, prevent wind tunneling, and thus prevent wind erosion.
It may take several pilot projects that integrate these practices to bring attention to their promise of value for wind management. However, combining these practices at a watershed scale will have multiple benefits for optimal water capture and storage, soil health, ecological integrity, and increased land productivity. The ongoing climate crisis and its prospects for the Southwest urge us to act now to explore appropriate responses to the underestimated impacts of wind on the landscape.
1 https://www.nrcs.usda.gov/Internet/NRCS_RCA/reports/nri_eros_nm.html, accessed 11/13/2021
2 https://infosys.ars.usda.gov/WindErosion/problem/problem.shtml, accessed 11/13/2021
Ecotone is looking for partners and funding for pilot projects to develop innovative, integrated land management responses to wind impacts. *CLICK HERE* to contact Jan-Willem Jansens if interested.