There are two crop residue/fresh organic matter pools (structural and metabolic), for representing recalcitrant and easily decomposable residues, based on residue lignin and N content.

• 作物剩留/新鲜有机质有两个库（结构性的与代谢性的），代表难分解与易分解的剩留物，这个区别是建立在木质素与N含量基础之上的。