Assessing soil quality for sustainable agricultural systems in tropical countries using spectroscopic methods

Identifying and developing appropriate methods to quantify and assess changes in soil quality are essential for evaluating the extent of soil degradation and the effectiveness of improved management practices. The objective of this research, which will be conducted across a wide range of cropping systems and environments in Asia, Africa and South America, is to determine the efficacy of spectroscopic-based (i.e. near-infrared, mid-infrared, and visible range) analytical methods to evaluate soil organic matter fractions and soil quality in degraded and non-degraded soils. Initial activities of the project are to develop in-field and laboratory analytical methodologies for the spectroscopic-based procedures, conduct comparisons of use of those methodologies in different cropping systems and climates that have experienced soil degradation, and collect soil samples from representative degraded and non-degraded soils for additional characterization of their soil C and N fractions. Among the methodologies to be tested are diffuse reflectance infrared Fourier-transformed (DRIFT) mid-infrared spectroscopy, near-infrared spectroscopy (NIR), and use of the in-field potassium permanganate test. Additional assessment of the criteria used to evaluate the results from these tests will also be discussed.