Evaluation of Poultry Litter and Organic Fertilizer Rate and Source for Production of Organic Short-day Onions

In a 3-year study of poultry litter applications on short-day onion (Allium cepa) production, where rates ranged from 0 to 10 tons/acre, there was an increasing linear effect on total onion yield. Jumbo (‡3 inches diameter) onion yield did not differ with increasing poultry application rates, while medium (‡2 and <3 inches diameter) yields decreased with increasing applications of poultry litter. In addition, organic-compliant fertilizers, 4N–0.9P–2.5K at 150 to 250 lb/acre nitrogen (N), as well as 13N–0P–0K at 150 lb/acre N and in combination with 9N–0P–7.5K totaling 150 lb/acre N were evaluated. Comparison of these commercial organic-compliant fertilizers indicated that there were no differences in total or jumbo yields, while medium yields generally decreased with increased N fertilizer rate.