Sunn-Hemp Utilized as a Legume Cover Crop for Corn Production
- Kipling S. Balkcom *a and
- D. Wayne Reevesb
The benefits of winter legumes as cover crops for corn (Zea mays L.) are diminished by the earliness of corn planting in relation to biomass and N production by the legumes. Tropical legumes may offer an alternative to winter legumes because they produce adequate biomass before corn planting. We determined the suitability of ‘Tropic Sunn’ sunn-hemp (Crotalaria juncea L.) as a cover crop for corn on a Compass loamy sand (coarse-loamy, siliceous, subactive, thermic Plinthic Paleudults) in central Alabama using a split-plot treatment structure in a randomized complete block design with four replications from 1991 to 1993. Main plots were winter fallow and sunn-hemp planted in mid-August, and subplots were N (0, 56, 112, and 168 kg N ha−1) applied to corn 3 weeks after planting (WAP). Sunn-hemp biomass production approximately 14 WAP (first frost) averaged 7.6 Mg ha−1 with an N content of 144 kg ha−1 in the first 2 yr of the study. Corn grain yield following sunn-hemp averaged 6.9 Mg ha−1 whereas yield following winter fallow averaged 5.7 Mg ha−1 Grain N averaged 16.3 kg ha−1 greater for corn following sunn-hemp than fallow plots. Before first frost, sunn-hemp produced excellent biomass to serve as a winter cover crop in corn production while producing N equivalent to 58 kg ha−1 of N fertilizer during the 3-yr period, based on corn yield and N response. Sunn-hemp has potential to be utilized as an alternative to winter legumes for ground cover and as an N source for a subsequent corn crop in the Southeast.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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