1. Visible and near-infrared spectroscopy in Poland: from the beginning to the Polish Soil Spectral Library – Guillaume Debaene
Worldwide, there is a growing interest in the use of visible and near-infrared spectroscopy (VIS-NIRS) to characterise soils. The method is largely used in the agricultural (foods and cereals) sector but is only in the research phase for soil analysis despite the fact that it is a suitable tool for precision agriculture. A quick search at the Web of Science (WoS) Core Collection confirmed that the method, although very popular in different fi elds of research, is still new within soils studies in Poland. Furthermore, the method only occasionally involved arable soils. This paper briefl y describes how VIS-NIRS is used in Poland and demonstrates with a few examples the main advantages of the method over classical analytical method for mineral soil analysis. As an illustration of the method potential, soil organic carbon (SOC) and clay content were predicted using partial least-square (PLS) regression at fi eld and national scale. The models were robust at field scale and revealed a high agreement between measured and predicted values with e.g. r2 = 0.65 and RMSEv = 0.11% for SOC. Prediction results at national scale are promising but less robust. VIS-NIRS is a suitable technique to estimate several soil properties at different scales and at a relatively low cost.
Keywords: Visible and near-infrared spectroscopy, soil spectral library, soil organic carbon, clay content