Matt A. Yost

On-farm soil health evaluations: Challenges and opportunities

Interest in soil health (or soil quality) by producers, conservationists, environmentalists, agricultural scientists, policy makers, and many other groups has increased exponentially during the past five years. Yet questions remain: can soil health be measured at the field or farm scale, and can that data be used to improve land management decisions and thus help protect, conserve, and restore our fragile soil resources? Our opinion, based on three years of experience through the Soil Health Partnership (SHP), is that the answer to both of these questions is a resounding yes! Recognizing that several other public and private groups are now expressing interest in assessing soil health, our goals are to (1) summarize several of the SHP lessons learned during the past three years, (2) provide guidelines for future on-farm soil health studies, and (3) share some of our preliminary soil health assessment findings. EVOLUTION OF THE SOIL HEALTH PARTNERSHIP The SHP is a farmer-led initiative of the National Corn Growers Association developed in 2014 with financial and technical support from Monsanto, the USDA Natural Resources Conservation Service (NRCS), United Soybean Board, Walton Family Foundation, Midwest Row Crop Collaborative, Environmental Defense Fund, and Nature Conservancy. The SHP defines soil health as…

Public–private collaboration toward research, education and innovation opportunities in precision agriculture

Regular assessment of precision agriculture (PA) knowledge gaps and opportunities, of PA’s relationship to decision and sustainable agriculture, and of the roles of various research and educational institutions helps advance the development, use and adoption of this science. It also helps to limit redundancy in a science that is rapidly evolving. Such assessments were conducted during a 2016 roundtable discussion by 32 public-sector and industry scientists, administrators and stakeholders predominately from the United States but also from Brazil, Canada, Germany, Israel, New Zealand, South Korea, and the United Kingdom. This article synthesizes those discussions and presents perspectives on developing coordinated, useable decisions from PA to meet sustainable agriculture goals. It concludes with milestones needed to advance PA research and development. Results will guide both public and private researchers and other stakeholders seeking to develop PA to help meet national and global sustainability goals for agriculture. These efforts will also act as a catalyst for regular discussions on PA research, education and development opportunities and coordination between public and private institutions in international forums on PA. Expected impacts include global action to help bring PA techniques and technologies into the mainstream of farming systems and acceleration of the interaction of genetics, environment, management and socioeconomic [(G × E × M) S] approach to sustainably intensify agriculture.

Field variability and vulnerability index to identify regional precision agriculture opportunity

Innovations in precision agriculture (PA) have created opportunities to achieve a greater understanding of within-field variability. However, PA adoption has been hindered by uncertainty about field-specific performance and return on investment. Uncertainty could be better addressed by using innovative analyses that provide insights into variability among fields and across a region. The objectives of this research were to: (1) generate a within-field soil clay-content variability index (VIc), (2) create a regional-scale growing-season precipitation variability index (VIp), and (3) integrate the soil and weather indices with the USDA NRCS soil erosion vulnerability index (SVI) to produce a final index that incorporated both variability and vulnerability (VVI). The interpretation of the outcomes represented by each objective supports unique decisions that land managers may consider for reducing uncertainty about implementing PA. All indices were derived using publically available information for Missouri, USA. The VIc was the ratio between the maximum and minimum clay content within fields. The VIp was calculated as the standard deviation of the total growing-season precipitation from 2006 to 2015. Significant clustering of VIc and VIp were observed along the Missouri River corridor, northeast and northwest Missouri. Fields with high VVI were mostly in the claypan soil region of northeast Missouri, and along a portion of the Missouri River dominated by loess soils on steep slopes. Southeast Missouri displayed the greatest diversity in soil and weather variability, but had low vulnerability. This research could be used as a decision-support tool to aid producers and PA service and product providers in determining where PA opportunities exist.

Evaluation of the Haney Soil Health Tool for corn nitrogen recommendations across eight Midwest states

Use and development of soil biological tests for estimating soil nitrogen (N) availability and subsequently corn (Zea mays L.) fertilizer N recommendations is garnering considerable interest. The objective of this research was to evaluate relationships between the Haney Soil Health Test (HSHT), also known as the Soil Health Tool or Haney test, and the economically optimum N rate (EONR) for corn grain yield at 17 sites in eight Midwest US states in 2016. Trials were conducted with a standard set of protocols that included a nonfertilized control plus six N rates applied at planting or as a split between planting and sidedress, soil samples for the HSHT prior to planting, and grain harvest at physiological maturity, and determination of EONR for each N application timing. Results indicated that HSHT recommendations with expected yield accounted for ≤28% of the variation in EONR among sites and N timings. Two components of the HSHT not directly used in the HSHT N recommendation for corn, the soil health calculation, or soil health score, and the Solvita carbon dioxide (CO2)-Burst lab test, accounted for the most variation in EONR. These two components were moderately related (R2 = 0.29 to 0.39) to soil organic matter (OM), highly related (R2 = 0.98) with each other, and subsequently both accounted for over one-half (R2 = 0.55) of the variation in EONR for N applied at planting or as a split. With additional research, these two components may help improve N recommendations for corn in the Midwest, especially Solvita CO2-Burst because it costs less to determine than the soil health calculation.

Miscanthus × Giganteus Growth and Nutrient Export on 22 Producer Fields

On-farm assessments of Miscanthus × giganteus growth and nutrient export across a wide range of management and environmental conditions are needed to determine and model how this crop performs and where it should be placed on the landscape. Therefore, Miscanthus growth and nutrient concentration and nutrient export at harvest were monitored during 2014 and 2015 at several landscape positions within 22 commercial production fields in central and southwestern Missouri and northeast Arkansas. Miscanthus shoot density and/or yield were best when it was grown: (i) following pasture converted to annual row crops or following row crops, (ii) on soils with colluvium parent material, (iii) on north-facing backslopes or footslopes, (iv) on soils with medium to fine texture, and (v) on well-drained/high runoff/low available water soils. Factors influencing nutrient concentrations varied by nutrient, but all concentrations consistently decreased as stands matured and most were more influenced by weather than were yield or nutrient export. Most effects on nutrient export were similar to effects on yield, but some nutrient exports were also influenced by manure history and weather conditions. Overall, cropping history prior to Miscanthus, landscape position, and soil properties such as parent material, soil textural class, and drainage class had the largest influence on Miscanthus growth and nutrient concentrations and exports. Weather conditions and inferior soils did not strongly influence Miscanthus production, but excessive soil moisture caused by various soil and weather factors often limited its growth. Thus, Miscanthus may be especially well-suited following annual crops on erosion-prone soils that drain well and have slope. These results will assist with the strategic cultivation of Miscanthus on Midwest landscapes.