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Dryland soil carbon dynamics under alfalfa and durum-forage cropping sequences
- Forages grown in rotation with or without cereals to sustain dryland soil water content and crop production may influence C dynamics. We evaluated the effect of alfalfa (Medicago sativa L.) and durum (Triticum turgidum L.)-annual forage cropping sequences on above- (stems+leaves) and belowground (roots) biomass C inputs and dryland soil organic C (SOC), particulate total C (PTC), microbial biomass C (MBC), and potential C mineralization (PCM) at the 0-120cm depth. Cropping sequences were continuous alfalfa (CA), durum-barley (Hordeum vulgare L.) hay (D-B), durum-foxtail millet (Setaria italica L.) hay (D-M), durum-Austrian winter pea (Pisum sativum L.)/barley mixture hay (D-P/B), and durum-fallow (D-F). The experiment was conducted in a Williams loam (fine-loamy, mixed, superactive, Typic Argiustoll) from 2002 to 2005 in eastern Montana, USA. Except in 2003, aboveground biomass yield and C content were lower in CA than in other treatments from 2002 to 2005. Similarly, belowground biomass yield and C content were lower in D-F than in other treatments from 2003 to 2005. In 2005, soil surface residue amount and C content were greater in D-F than in other treatments. The SOC at 0-15cm was greater in CA than in D-B and D-M. The PTC at 0-15cm was greater in CA than in other treatments, but varied with treatments at other depths. The PCM at 0-120cm was greater in CA than in other treatments. The MBC at 30-120cm was greater in CA and D-P/B than in D-B. The proportion of SOC in PTC, PCM, and MBC at 0-120cm was greater in CA or D-P/B than in D-B and D-F. Although aboveground biomass C input was lower, greater belowground biomass C and a relatively undisturbed soil condition probably increased C storage at the surface layer and microbial biomass and activity at the surface and subsurface layers under alfalfa than under annual durum-forage sequences. Greater aboveground biomass C and fresh residue accumulation during durum phase, however, increased C storage in the surface residue under durum-fallow than under other cropping sequences. Perennial forages, such as alfalfa, can increase dryland soil C sequestration and biological soil quality by increasing microbial biomass and activity compared with annual cropping systems due to greater belowground biomass C input and continuous root growth.
Sainju, Upendra M. , Lenssen, Andrew W.
Hordeum vulgare , Medicago sativa , Pisum sativum , Setaria italica , Triticum turgidum , aboveground biomass , alfalfa , belowground biomass , carbon , carbon sequestration , continuous cropping , crop production , cropping sequence , forage crops , hay , irrigation , microbial activity , microbial biomass , microbiological quality , millets , mineralization , peas , root growth , soil nutrient dynamics , soil organic carbon , soil quality , soil water content , Montana
- Includes references
- Soil & tillage research 2011 May, v. 113, no. 1
- Elsevier Science
Journal Articles, USDA Authors, Peer-Reviewed
- Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.