Soil Regeneration and Health

Amy Larsen, Dr. Johnson, and Tom Dominguez Beside Johnson-Su Bioreactor Compost Bin
Amy Larsen, Dr. David Johnson, and Tom Dominguez Beside Johnson-Su Bioreactor Compost Bin (Photo Taken by Adrienne Rosenberg)

Soil health may be the most important factor for farming success, especially in the arid Southwest. Today's soil is challenged by the effects of modern human inhabitance such as salinization, pollution, soil loss, and reduced water retention. Although we often think of soil as inert and uniform dirt, it can be viewed as comprising three major components: chemical, physical, and biological. Together these make any soil sample deeply complex.

For Amy Larsen, Senior Research Assistant, the solution for vibrant soil is growing the microbial community or microbiome. Larsen is currently initiating a series of trials with a static, aerobic composting process that was designed and developed by NMSU researcher Dr. David Johnson and Hui-Chun Su Johnson. By encouraging microbial communities to increase both in numbers of organisms and in diversity, the Johnson-Su bioreactor composting system produces a "high quality" nutrient-rich, fungal-dominated, high microbial biomass, and biodiverse compost. Based on preliminary experiments, soil inoculated with the bioreactor compost benefits with faster and greater biomass growth, a more efficient transfer of carbon, reduced soil respiration rates, and increased soil fertility. Larsen intends to observe and measure the cultivation of diverse microbial communities and the potential for increased crop yields. In addition, she seeks to standardize the system so that everyday farmers can inoculate their soils with a radiating, fungal dominant network of interacting microbes without the need for a lab or a microscope.

SASC Alcalde Publications

  • Compost as a Microbial Inoculant (Poster; PDF)
    Created by Amy Larsen and presented at the Soil Science Society of America 2019 Conference, this poster illustrates the current Johnson-Su Bioreactor Composting System study conducted at SASC Alcalde.

Additional NMSU Publications

Power Points, Circulars, and How-to Guides

  • Best Management Practices: Johnson-Su Composting Bioreactors (Powerpoint, PDF)
    Compost-amended soils have existed for over 5,000 years in the tropical soils (terra preta) of Amazonia, more than 4,000 years in Asia and Japan, over 2,500 years as plaggen soils in the Netherlands, more than 850 years in cultivated soils called chinampas in Meso-America, and 1,000 years in the altiplanos of Bolivia. Some of these soils, created as a consequence of human activity, remain more fertile and more productive than the surrounding soils to this day. This longevity of soil fertility provides good evidence that composting is beneficial, and if we are to achieve long term sustainability in our agricultural systems, it may be advantageous for us to start emulating the composting activities of nature and our ancestors. This document guides the reader through building a Johnson-Su Bioreactor.
  • Circular 555_Conservation Farming in New Mexico
    Bare soils, associated with conventional tillage, lead to severe soil erosion from both wind and water. In contrast, conservation tillage is any tillage or planting practice that maintains at least 30% crop residue cover on the soil surface at planting time to reduce soil erosion by water, or, where soil erosion by wind is the primary concern, maintains at least 1000 lb/ac of flat, small grain residue equivalent on the surface during the critical erosion period This article reviews conservation tillage, the costs of conventional tillage, and how to implement conservation tillage.
Amy Larsen Holding a Hand Full of Soil
Amy Larsen Holding 5 Month Old Bioreactor Compost (Photo Taken by Adrienne Rosenberg)
  • Circular 650_Sulfur and New Mexico Agriculture
    Sulfur-deficient soils are often low in organic matter, coarse textured, well drained, and subject to leaching because sulfate is mobile in the soil. In semi-arid regions, SO4-2 can accumulate in the lower soil profile as soluble gypsum. The S status of New Mexico's soils is not well defined, and S effects on the growth of New Mexico crops have not been extensively researched.
  • Circular 656_An Introduction to Soil Salinity and Sodium Issues in New Mexico
    Salts are necessary for providing many of the minerals that both plants and humans need in order to be healthy. Too much salt is unhealthy for humans as well as plants. High salt in the plant root zone interferes with the uptake of water and can cause death. It does not matter to the plant what kind of salt it is. Thankfully, plants have different levels of tolerance to salts found in the soil or in irrigation water. Since salts can conduct electricity when dissolved in water, we can measure the total "saltiness" of a soil by using a water extract and measuring how well the water conducts electricity. We can combine this measure of saltiness with knowledge of how plants respond to the salt to improve productivity using optimum soil management and plant selection.
  • Circular 687_Managing Organic Matter in Farm and Garden Soils
    Organic matter is an important component of the soil. Soil organic matter helps improve the soil’s water-holding capacity, structure, bulk density (aeration), cation exchange capacity, microbial activity and diversity, and nutrient reserves. Many soils in New Mexico are low in organic matter and can benefit from managing soil organic matter to improve the overall productivity of the soil. Organic matter can be added in the form of composts, manures, and plant material, or can be grown in place as plants (cover crops and green manures) and incorporated back into the soil. But before adding anything to the soil, you should understand some basic principles of soil organic matter.
  • Circular 690_Biochar for Arid and Semi-arid Agricultural Soils
    Biochar is black carbon or charcoal made from biomass- biological, organic materials derived from plants and animals. Biochar is created by heating biomass in an environment that has little or no oxygen (Figure 1), a process called pyrolysis. The net effect of pyrolysis is the production of a solid material (biochar) that has a high concentration of carbon and does not easily break down in the soil. By applying biochar to the soil, the soil’s carbon content can be increased significantly. This added carbon can persist in the soil for a very long time (carbon sequestration).
  • Guide H 110_Backyard Composting
    Yard waste makes up 20–30 percent of the solid waste of most municipalities throughout the United States, while food waste makes up another 8–9 percent. Yard and food wastes are also major factors in the production of methane gas and acid-liquid drainage in land fills. Incinerating yard wastes is a major source of air pollution. Although municipal composting is an environmentally preferable alternative for handling yard and food wastes, processing these wastes at the source reduces the major costs of collecting and has a positive effect on the environment. Backyard composting is one of the easiest ways to process yard wastes at the source.
  • Guide A 114_Test Your Garden Soil
    Soil tests provide a scientific basis for regulating available plant nutrients. Recommendations on soil management practices are based on test results. Tests on a sample that does not accurately represent your garden or field's soil are likely to be misleading. The directions in this NMSU Guide can help you take a representative sample.
Close up of measuring the soil strata with a ruler
Amy Larsen Measuring Soil Sample (Photo Taken by Adrienne Rosenberg)
  • Guide A 146_Appropriate Analyses for New Mexico Soils
    Soil testing helps us understand the soil environment in which our plants must survive. A complete understanding of the soil would include its physical, chemical, and biological properties. Management practices affect all three of these categories. Soil testing provides a "snapshot" of what conditions were like at the time of sampling, and this allows farmers and homeowners to plan their management practices for the coming growing season. The focus of this publication is to provide guidance for people interested in knowing more about their New Mexico soil from a chemical and physical perspective.
  • Guide A 148_Understanding Soil Health for Production Agriculture in New Mexico
    Since soil is such an important component of the natural ecosystem, careful management of the soil is essential to sustain its utility. Conventional commercial farming depends heavily on the careful management of soil nutrients to promote adequate crop yields of food, feed, and fiber. This has resulted in the development of precise nutrient analytical methods with accompanying recommendations to address nutrient deficiencies in different soils that are used for farming. While this strategy has improved productivity over a long period of time, scientists are now finding that managing soil for nutrients alone may not lead to sustainable crop production in the long term. Other aspects of the soil, including aggregate stability, infiltration rate, salinity, sodicity, and mineralization potential, need to be addressed to attain the goal of sustainable crop production (Idowu et al., 2008).
  • Guide A 150_ Principles of Cover Cropping for Arid and Semi-arid Farming Systems
    Cover crops are crops grown in between cash crop cycles, intercropped with cash crops, or planted in the absence of a normal crop (Reeves, 1994). They are grown to protect the land from soil erosion and loss of nutrients (Reeves, 1994) and to add organic matter to the soil, which can lead to increased soil microbial populations and diversity (Drinkwater et al., 1995). Cover cropping is an important component of sustainable agricultural systems because it helps build soil health and makes the soil more resilient to drought and other extreme environmental factors (Doran and Zeiss, 2000). This publication summarizes cover crop options along with benefits and challenges to their adoption in arid and semi-arid environments, including New Mexico.
  • Guide A 152_Reducing Tillage in Arid and Semi-arid Cropping Systems: An Overview
    Reduced tillage is gaining attention among growers in the arid and semi-arid cropping systems of New Mexico and other parts of the Southwest because of the undesirable effects conventional tillage has on the environment and soil quality, as well as economic benefits associated with less intensive tillage operations. Conventional tillage, which presently is the preferred land preparation method used by growers in this region, has led to accelerated soil erosion by wind and water as well as degraded soil quality. Conventional tillage management often involves one or more of the following practices: plowing, ripping or subsoiling, and disking and harrowing.
  • Guide H 164_Vermicomposting
    Yard and food waste make up a major component of solid waste in most cities and towns throughout the United States. Although much of this organic waste can be recycled in the backyard using traditional aerobic backyard composting techniques, these techniques are not appropriate for apartment dwellers and are often inconvenient, particularly during bad weather in the winter.
  • Guide H 637 PH 4 206_A Practical Way of Measuring Soil Moisture
    Irrigation efficiency in orchards is extremely important in the arid West where almost all the water needed come from irrigation water. Orchardists should check water penetration after each irrigation to ensure the appropriate soil moisture depth for optimum tree growth. Although this guide is geared to pecan growers, it is generally applicable to other orchardists.

NMSU News Center

Additional Links


Nematode in Bioreactor Compost 400 tot. mag.
Nematode in SASC Alcalde Bioreactor Compost 400 tot. mag. (Microscope Photo Taken by Amy Larsen)
  • NMSU: Understanding Western Soils (Animations and Videos)
    This series provides guidance on how to sample soil for analysis and includes visualizations related to soil properties and water infiltration. Concepts such as particle size, soil water-holding capacity, runoff, leaching, sodium adsorption ratio, sodic soils, and saturated paste are explored. Short video demonstrations assist with teaching or learning. The series focuses on arid soils, such as those found in the American West.
  • NRCS: Guide to Soil Texture by Feel
    Not all laboratories evaluate soil texture as part of their normal fee structure. Many labs will estimate texture or perform a specific test to determine soil texture for an additional fee. Texture can be estimated at home or on the farm with the "feel" method by using the USDA NRCS's guide found in Gee and Bauder (1986).

Johnson-Su Bioreactor Compost

  • California State University: Dr. David Johnson's Research on Fungal-Dominated Compost and Carbon Sequestration
    Dr. David Johnson, Adjunct Professor for the College of Agriculture at Chico State and Faculty Affiliate for the Regenerative Agriculture Initiative, is investigating the use of biological soil enhancements and its effect on carbon sequestration for the Institute of Sustainable Agricultural Research at New Mexico State University. In particular, he found that the ratio between fungi and bacteria in the soil is critical to a plant’s productivity in healthy agricultural systems and thus to a plant’s efficiency in nutrient uptake. It also increases the rate of carbon sequestration significantly.