An Investigation into the Carbon and Total Nitrogen Content of Suspended Sediments in Değirmendere Watershed and Its Implications for Erosion Risk

Abstract

Soil erosion presents a global challenge, leading to severe repercussions such as soil degradation, compromised water quality, reduced agricultural output, and ecological harm, endangering life's sustainability on Earth. To preserve soil fertility and water quality within a watershed, it is crucial to compute soil loss quantities, sediment delivery ratios (SDRs), and nutrient concentrations within suspended sediments (SS). The Değirmendere watershed in Turkey's Trabzon province was selected for research area. The study employed the RUSLE method in coupled with Geographical Information Systems to quantify soil loss and SDR. Direct measurement techniques were used to calculate the annual SS, as well as carbon (C) and total nitrogen (TN) content within the SS. Over a span of twelve months spanning January to December 2019, water samples were collected. The outcomes revealed that the watershed experiences annual amount of soil erosion is 592,140 tons year−1 with an average rate of 5.61 tons ha−1 year−1 . The sediment delivery ratio (SDR) was calculated to be 0.38. Other analysis indicated that the annual estimated sediment load and the directly measured annual quantities are 225 013 and 97 660, respectively. Both directly measured and predicted suspended sediment contain 0.15% TN and 1.13% C. The estimated sediment load is nearly two and a half times greater than the direct stream measurement (y=2.304x). The outcomes of this research carry important implications for upcoming studies focused on the preservation of soil and water, a crucial measure in reducing soil erosion and improving water quality. The study provides guidance for future investigations concerning soil and water conservation.