Portable, In-Situ Determination of Soil Nutrients

Abstract

The sustainable future of our world depends fundamentally on soil fertility and the fine balance between soil nutrients and the physical soil environment. In order to feed 7 billion people, humans have more than doubled global land-based cycling of nitrogen (N) and greatly influenced cycles of other major nutrients (e.g. carbon (C), phosphorus (P), potassium (K) and Sulphur (S)). As a consequence, they are now out of balance, causing major environmental, health and economic problems. Insufficient access to nutrients limits food production and contributes to land degradation, while finite P reserves represent a potential risk for future global food security, requiring prudent use.These issues warrant effective soil management strategies across different spatial and temporal scales. Ultimately, this depends on how accurately we can measure nutrient levels in soils over a large area in real-time with a high spatial and temporal resolution that is economically feasible.In the last several years, we are focusing our efforts on modification and adaptation of Ion Selective Electrodes (ISEs) that hold great promise for in situ analysis of plant nutrients. Unfortunately, relatively poor precision and robustness as well as requirements for pre- and post measurement handling prohibit their reliable use in the field by non-trained personnel (e.g. farmers) which is our ultimate goal.We will herein describe and discuss our efforts on the development of significantly simplified sensor substrates, measuring protocols, and integration with statistical methods aimed at improvement of precision. Moreover, we will demonstrate recent data obtained using our newly developed portable device that allows in situ determination of up to 16 analytes enhanced with the wireless data transmission capability.