Korean Journal of Soil Science and Fertilizer ISSN:0367-6315(Print) 2288-2162(Online) 한국토양비료학회 학회지

Green manure, used for eco-friendly agriculture, supplies organic matter (OM) and nutrients to soil and improves soil fertility. Green manuring also has the potential to affect physical stability and carbon storage. The objective of this study was to investigate the effect of green manure on water-stable soil aggregates and carbon stock in paddy. Soil samples were collected from 3 treatments in Chungcheongnam-do Agricultural Research and Extension Services on 29 April 2022; Control (CN), Green manure treatment (GM), and Chemical fertilizer treatment (NPK). Water-stable aggregate fractions (<53 µm, 53 - 250 µm, and >250 µm), carbon contents in bulk soil and aggregate fractions, and total carbon stock were analyzed. Carbon content in GM was 15% higher than in NPK. However, there was no significant difference in soil carbon stock (Mg C ha^-1) in GM and NPK. Water-stable aggregate ratio (%) and carbon percent of macro-aggregates (>250 µm) and micro-aggregates (53 - 250 µm) in GM were significantly higher than in NPK. As a result, green manure promoted soil aggregation and stabilized carbon in soil aggregates. These results confirmed that green manure, used for nutrient supply, improves soil carbon storage and soil physical stability.

Distribution of water-stable aggregate and carbon of each fraction in treatments: CN, control; NPK, chemical fertilizer treatment; GM, green manure treatment. Vertical bars represent standard deviations (n = 3) and different letter in the same aggregate size indicates significantly different at the 5% level by DMRT.