The successful use of winter cover crops (WCCs) in short rotations depends on adequate management of their residues. To improve management decisions, there is a need to understand the factors controlling WCC residue decomposition rates and nutrient release rates. A 2-yr study was conducted to estimate residue decomposition and C and N release rates using principal-component regression (PCR) based on WCC biochemical fractions at the time of WCC killing. Rye (Secale cereale L.), hairy vetch (Vicia villosa L.), and rye-hairy vetch biculture were planted as WCCs in the fall and chemically killed in the spring before no-till-planting corn (Zea mays L.). At killing time, residues were analyzed for total C and total N concentrations, neutral detergent fiber (NDF) and acid detergent fiber (ADF), and C and N concentration in the NDF and ADF. Concentration of C and N in neutral detergent soluble fractions (NDSOLC and NDSOLN, respectively) and acid detergent soluble fractions (ADSOLC and ADSOLN, respectively) were calculated. Principal components (PCs) 1, 4, 5, and 7 were selected as significant predictor variables for biomass decomposition and C and N release rates. The PC1 scores suggest that large concentrations of NDF and ADF are associated with low biomass decomposition and slow C and N release rates. Other important fractions are C and N concentration in the NDF and NDSOLC, NDSOLN, ADSOLC, and ADSOLN. The availabilities of C and N, rather than their total concentration in the residue, play a critical role in residue decomposition and nutrient release.
|Original language||English (US)|
|Number of pages||7|
|State||Published - Jul 1 2003|
ASJC Scopus subject areas
- Agronomy and Crop Science