| Autor: |
Schmer, M.R., Jin, V.L., Wienhold, B.J., Varvel, G.E., Follett, R.F. |
| Zdroj: |
Soil Science Society of America Journal; November 2014, Vol. 78 Issue: 6 p1987-1996, 10p |
| Abstrakt: |
Demand for corn (Zea maysL.) stover as forage or as a cellulosic biofuel has increased the importance of determining the effects of stover removal on biomass production and the soil resource. Our objectives were to evaluate grain yield, soil organic C (SOC), and total soil N (0–150 cm) in a 10‐yr, irrigated, continuous corn study under conventional disk tillage (CT) and no‐till (NT) with variable corn stover removal rates (none, medium, and high). Natural abundance C isotope compositions (δ13C) were used to determine C additions by corn (C4–C) to the soil profile and to evaluate the retention of residual C3–C. After 10 yr of management treatments, mean grain yields were 7.5 to 8.6% higher for NT when stover was removed compared with no stover removal, while grain yields were similar for CT in all stover removal treatments. Turnover of SOC occurred as C3–C stocks were replaced by C4–C in the 0‐ to 120‐cm soil profile. Total SOC and N stocks changed mainly in surface soils (0–30 cm), with no detectable cumulative changes at 0 to 150 cm. Specifically, SOC declined after 10 yr under CT at 0 to 15 cm and was affected by residue management at 15 to 30 cm. Total soil N was greater when no stover was removed (P= 0.0073) compared with high stover removal at 0 to 15 cm. Long‐term NT ameliorated medium stover removal effects by maintaining near‐surface SOC levels. Results support the need to evaluate SOC cycling processes below near‐surface soil layers. |
| Databáze: |
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