Tillage, Cover Crop, and Kill-Planting Date Effects on Corn Yield and Soil Nitrogen
- Upendra M. Sainju * and
- Bharat P. Singh
Tillage and spring kill date may affect cover crop N accumulation and subsequent N release to the soil, thereby influencing corn (Zea mays L.) N uptake and yield. We examined the influence of three tillage practices [no till (NT), chisel plowing (CP), and moldboard plowing (MP)], two cover crop management systems [hairy vetch (Vicia villosa Roth) vs. winter weeds], and two cover crop kill–corn planting dates [early (early April cover crop kill and mid to late April corn planting) vs. late (mid to late April cover crop kill and late April to early May corn planting)] on cover crop N accumulation, soil inorganic N, and silage corn N uptake and yield. An experiment was conducted on a Dothan sandy loam (fine-loamy, siliceous, thermic, Plinthic Paleudults) from 1997 to 1999 in central Georgia. Cover crop N accumulation was higher with late kill than with early kill (113 vs. 104 kg ha−1). Corn yield was higher with late planting in NT than in CP or MP (19.5 vs. 15.1–16.6 Mg ha−1) and higher in CP or MP with early planting than in MP with late planting (18.1–18.4 vs. 15.1 Mg ha−1). Similarly, corn N uptake was higher in NT with late planting than in CP or MP with early or late planting (217 vs. 133–171 kg ha−1). Soil inorganic N (0- to 30-cm depth) at corn planting was higher in CP than in NT (18.4–30.2 vs. 9.9–20.5 mg kg−1). Corn yield and N uptake in NT and N concentration and uptake in CP and MP can be increased by delaying cover crop kill by 2 wk, but corn yield in CP and MP can be maintained by killing cover crop early in the spring.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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