In-situ assessment of soil-root bonding strength to aid in preventing soil erosion

Abstract

Research shows that construction of seawalls controls soil erosion along the coastal lines but scouring at the bottom deteriorates water clarity and causes algae growth. An environmentally friendly, sustainable solution such as controlled cultivation of plants has potential to perform better in such cases. Studies already show that plant roots’ tensile strength has direct influence on soil shear strength. However, the tensile strength tests performed in the lab cannot represent the exact ambient condition. This paper describes the development of a novel, effortless approach to carry and assemble an In-situ Smart Testing Apparatus (ISTA) that evaluates Soil Root Bonding Strength (SRBS) by pulling vegetation with roots out of the soil and measures and records the pulling strength along with the vertical displacement that takes place during the uprooting process. Another aspect of the equipment includes in-situ tensile testing capability of plant roots. In addition to those, the controlling program of the equipment stores other parameters like test date and time along with the latitude, longitude, humidity, and temperature of test location in the same file. This paper includes the initial study conducted on four different naturally grown species (Ranunculus acris, Stenotaphrum secundatum, Paspalum urvillei, and Rhynchospora mixta) using the developed ISTA near a pond at the Agricultural Department at Louisiana Tech University. Different forces required to uproot the investigated plants indicate that SRBS could be stimulated by the types and arrangements of roots inside subsoil. The obtained results reveals a strong effect of plant types and soil phase properties (soil bulk density, moisture content, air content, and pore space) on SRBS in the form of pulling force and displacement. The ISTA, thus, has significant potential to measure, store and distribute the real time data that can aid relevant professionals in preventing soil erosion and ensuring sustainable coastal ecosystems.