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Winter Cover Cropping Influence on Nitrogen in Soil
Author(s) -
Kuo S.,
Sainju U. M.,
Jellum E. J.
Publication year - 1997
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1997.03615995006100050016x
Subject(s) - vicia villosa , cover crop , agronomy , lolium multiflorum , secale , soil quality , cropping system , green manure , mineralization (soil science) , environmental science , chemistry , biology , crop , soil water , soil science
Winter cover crops may affect the short‐ and long‐term N availability in soil depending on the quantity, quality, and degradation rate of biomass returned to the soil. We examined the effects of several cover crops on soil inorganic and organic N levels in a winter cover crop‐silage corn ( Zea mays L.) double‐cropping system that was initiated in 1987. High biomass N concentrations (BMN) in the above‐ and belowground biomass of the leguminous cover crops corresponded to high levels of inorganic N and water‐soluble N, but low levels of water‐soluble C and carbohydrate compared with the nonleguminous cover crops. The BMN above which there was net N mineralization 4 wk after residue incorporation was 17.9 g N kg −1 . The organic N from the aboveground biomass degraded rapidly. The first‐order rate constants for the degradation of organic N and C in the cover crops were significantly correlated. This, coupled with a significant correlation between the soil organic N (SON) levels and cumulative biomass C added, indicated the importance of biomass C inputs in organic N retention in the soil. The cover crops had variable short‐ and long‐term effects on soil N availability. Whereas rye ( Secale cereale L. cv. Tetra Petkus) and annual ryegrass ( Lolium multiflorum Lam. cv. Billion) were ineffective in increasing soil inorganic N levels, they were more effective than hairy vetch ( Vicia villosa Roth subsp. villosa ), Austrian winter pea ( Lathryrus hirsutus L.), and canola ( Brassica napus L. cv. Santana) in increasing SON accumulation because of a higher biomass potential and a larger input of biomass C.