Carbon dioxide emissions from buckwheat cultivation: Effects of mineral fertilizers

Abstract

The use of mineral fertilizers is a common agricultural practice aimed at increasing crop yields. However, both their production and application are sources of greenhouse gas emissions, contributing to global climate change, which adversely impacts various sectors of the economy, including crop production. The first step in developing successful climate change mitigation strategies is to define a “baseline scenario” of the system’s evolution without intervention. The aim of this study was to define a baseline scenario for buckwheat cultivation by assessing CO 2 emissions from soils under mineral fertilization in the foreststeppe conditions of the Middle Volga region. As part of the field experiment, mineral fertilizers were applied at two different rates: N 23 P 15 K 23 S 2 and N 47 P 30 K 46 S 5 . The control soil received no fertilizers. All soils were managed by conventional tillage. The following parameters were determined during the vegetation experiment (May–August 2024): soil temperature and moisture, organic matter content, organic carbon, microbial biomass carbon, soil CO 2 emissions, and buckwheat yield. Compared with the unfertilized control, the N 23 P 15 K 23 S 2 and N 47 P 30 K 46 S 5 treatments increased buckwheat yield by 16 and 19 %, respectively. In the absence of mineral fertilizers, the average soil CO 2 emissions were 0.038 g C/(m 2 ×h) at the beginning of the growing season, increased in June–July, and decreased by the end of the season to a level twice the initial value. The fertilizer treatments exhibited similar dynamics, yet with a non-significant reduction in CO 2 emissions and a significant increase in microbial biomass. No dependence of soil CO 2 emissions on the applied fertilizer rates was found. Thus, the application of the studied mineral fertilizers not only enhanced buckwheat yield but also led to a more optimal functioning of the microbial community without increasing soil CO 2 emissions.