Soil Health Indicators in Areas Affected by Pipeline Installation
Installation of the Dakota Access Pipeline (DAPL) in 2016 created a cross-section of disturbed soil from northwest to southeast Iowa. Since that time, farmers have observed lower crop yields along the path of the pipeline and have implemented a variety of management practices to address that issue. This situation creates a unique opportunity to study soil health and resiliency across a spectrum of soil types and management practices. The implications of measuring soil health on disturbed and adjacent undisturbed soil across this spectrum are far reaching. In the US, approximately 517,000 km of natural gas pipelines has been installed and another 6,200 km will be constructed in the coming years (Olson & Doherty, 2012). To date, studies conducted on the effects of pipeline installation on individual fields have observed that soil bulk density and pH tends to be increased while soil organic carbon (SOC) tends to be decreased (Naeth & Bailey, 1987; Soon et al., 2000; Yu et al., 2010; Antille et al., 2016; Tekeste et al., 2019). The proposed study will expand on previous work by stratifying soil samples by soil parent material, landscape position, management practice, and disturbed versus undisturbed areas. Samples collected every 30 cm to a depth of 90 cm will be measured for nitrate, organic matter, available phosphorous, exchangeable potassium, magnesium, calcium and hydrogen, pH, buffer index, cation exchange capacity (CEC), percentage of base saturation of cation elements, texture, and microbial activity. To estimate the plant available water (field capacity – permanent wilting point), one ring of 5 cm height will be taken every 30 cm to run in ceramic plates and pressure chambers. Results from the sampling will be used with a machine learning algorithm and remote sensing to produce maps of evaluated soil properties, illustrating the broader impact beyond the fields sampled. As a learning outcome, farmers will be informed on the current distribution of soil properties in relation to the pipeline in their fields and the potential underlying causes to their decreased crop yields. Once they have a better understanding of their soil issues, they will be better able to target their management practices to help their soil recover. The evaluation plan will include a survey evaluating farmers’ level of comfort with the results and rate of adoption for specific management practices to improve the soil in their fields.
Project objectives from proposal:
A unique dataset will be assembled of soil health indicators across a range of soil forming conditions and known time of disturbance. That dataset will be leveraged with geospatial technologies to produce a regional map illustrating the broader landscape effect of the pipeline on soil properties. The learning outcome will be to answer farmers’ questions about changes that may have occurred to the soil along the pipeline’s path and the effectiveness of the management practices they have implemented. As an action outcome, farmers will have the tools to switch from their current random treatments - ranging from cover crops to deep ripping tillage - to better informed and targeted practices. The benefit to farmers will be a reduction in their current, desperate mitigation strategies and the ability to strategically address the problem of decreased crop yields.