AN AUTOMATED SAMPLING SYSTEM FOR MEASURING SOIL pH

Characterising the within-field scale spatial variation of nitrogen in a grassland soil to inform the efficient design of in-situ nitrogen sensor networks for precision agriculture

“…Whilst the advantages of this approach in some situations have been evidenced (Diacono et al, 2013), plant N status and yield is the product of many variables and may not always correlate with soil mineral N status. On-the-go soil sampling for NO 3 À , using electrochemical sensor platforms attached to agricultural vehicles have been developed (Adsett et al, 1999) and, for the case of pH, commercialised (Adamchuk et al, 1999). The results have been used to develop field nitrate maps (Sibley et al, 2009) which could be used to define within-field management zones and to calculate variable fertiliser application rates.…”

In situ measurements of soil colour, mineral composition and clay content by vis–NIR spectroscopy

“…For example, the use of electromagnetic induction (EMI) and electrical resistivity for measurements of soil electrical conductivity (Sudduth et al, 2001), magnetic susceptibility for measuring soil contamination by heavy metals (Jordanovaa et al, 2008), ground penetrating radar (GPR) for measurements of soil water content (Pettinelli et al, 2007), proximal passive γ-ray spectrometry for measuring K, U, Th, sand, clay and iron contents , cameras to measure soil colour and estimate soil organic carbon and iron contents (Sudduth and Hummel, 1988;Viscarra Rossel et al, 2008), diffuse reflectance spectroscopy using visible-near infrared (vis-NIR) and mid infrared (mid-IR) energies to estimate soil organic carbon (OC), clay content, mineral composition and other soil properties (e.g. BenDor and Banin, 1995;Stenberg et al, 1995;Reeves and McCarty, 2001;Shepherd and Walsh, 2002;Demattê et al, 2004;Brown et al, 2006;Viscarra Rossel et al, 2006a), ion-sensitive field effect transistors (ISFET) and ion-selective electrodes to measure soil pH, lime requirement and soil nutrients (Adamchuk et al, 1999;Viscarra Rossel and Walter, 2004;Adamchuk et al, 2005;Viscarra Rossel et al, 2005;Sethuramasamyraja et al, 2008), and mechanical draft systems for measuring soil strength (Hemmat and Adamchuk, 2008).…”

Evaluation of an on-the-go technology for soil pH mapping

“…Based on the experience gained during the development of a field prototype system for mapping soil nitrate content and pH (Loreto and Morgan 1996), a follow-up research study was undertaken to investigate the applicability of flat-surface combination ion-selective electrodes (ISEs) to measure soil properties (particularly pH) directly on moist soil samples (Adamchuk et al 2005). The initial results illustrated a high correlation with conventional laboratory measurements (R 2 > 0.92), and a prototype automated system for mapping soil pH on-the-go was developed and tested (Adamchuk et al 1999). Later, a commercial implement utilizing this approach was developed (Christy et al 2004).…”