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Carbon and nitrogen in a F erralsol under zero‐tillage rotations based on cover, cash or hay crops
Author(s) -
Alburquerque M. A.,
Dieckow J.,
Sordi A.,
Piva J. T.,
Bayer C.,
Molin R.,
Pergher M.,
RibeiroJunior P. J.
Publication year - 2015
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12173
Subject(s) - lolium multiflorum , vicia villosa , agronomy , hay , legume , cover crop , no till farming , biology , soil water , soil fertility , ecology
To identify crop rotation systems capable of sequestering C and N to 1 metre depth in a subtropical Ferralsol of Southern Brazil managed under long‐term zero‐tillage (21 yrs), we evaluated six crop sequences: wheat ( Triticum aestivum )–soybean ( Glycine max ) [W‐S], the baseline; oat ( Avena strigosa , as cover crop)–maize ( Zea mays )–wheat–soybean [O‐M‐W‐S]; vetch ( Vicia villosa , as legume cover crop)–maize–wheat–soybean [V‐M‐W‐S]; vetch–maize–oat–soybean–wheat–soybean [V‐M‐O‐S‐W‐S]; ryegrass ( Lolium multiflorum , for hay)–maize–ryegrass–soybean [R‐M‐R‐S]; and alfalfa ( Medicago sativa , for hay)–maize [A‐M]. Compared to W‐S and to 1 metre, the hay‐based system of A‐M showed the largest C and N sequestration rates (0.50 and 0.06 Mg/ha/yr, respectively). Alfalfa, being a perennial legume under cut‐regrowth cycles, possibly added more C and N through roots. The other hay system, R‐M‐R‐S, also sequestered C efficiently (0.27 Mg/ha/yr), but not N (0.01 Mg/ha/yr). The legume‐based system of V‐M‐W‐S sequestered significant amounts of both C (0.29 Mg/ha/yr) and N (0.04 Mg/ha/yr). The grass‐based system of O‐M‐W‐S showed the lowest sequestration of C (0.09 Mg/ha/yr). In all systems, a positive relationship ( R 2 = 0.71) occurred between estimated addition of root C and soil C stock to 1 metre. Whenever C and N sequestration occurred, more than half of that occurred below 20 cm depth. Results suggest that adoption of legume‐based systems, perennially as A‐M or annually as V‐M‐W‐S, is efficient for C and N sequestration in subtropical zero‐tillage soils and that roots possibly contribute more to that sequestration than aboveground biomass.