Studies determined the potential of acid hydrolysis for estimating the bioreactive fraction of organic carbon in soils (SOC). Three soils (clay loam, silt loam, and sandy loam) were hydrolyzed with 1 M or 6 M HCl under reflux for up to 24 h. Results showed that 1.7 to 3.2 % of SOC could be liberated as CO2 from the acid hydrolysis of soil. This readily hydrolyzed fraction should be a part of the bioreactive SOC. Higher amounts of soluble SOC and N as well as CO2 were released from all soils by 6 M HCl than by 1 M HCl. Soluble SOC and N contents in both 1 M HCl and 6 M HCl hydrolysates of all soils increased rapidly during the initial 2 hours of hydrolysis, and then increased very gradually. The amounts of CO2-C evolved correlated with the amounts of NH4-N released during the acid hydrolysis (r = > 0.88). The ratio of SOC to soluble N was lower in 6 M HCl hydrolysate than in 1 M HCl. Hydrolysis of soil by 1 M HCl for 4 h appeared to be a promising approach for estimating the more bioreactive pools of SOC and N.
|Original language||English (US)|
|Number of pages||5|
|Journal||Nutrient Cycling in Agroecosystems|
|State||Published - Dec 1 1997|
- Acid hydrolysis
- Organic carbon
- Organic nitrogen