Thursday, November 16, 2006 - 11:10 AM
321-10
Nitrogen Management During Establishment of Organic Peaches.
The demand for organically grown fruit crops is increasing but supplying adequate nitrogen is challenging. Five double row-middle nutritional treatments were established in a 2001 planting of cling peach (Prunus persica (L.) Batsch cv. Klamt) orchard transitioning to organic production: subclover; soft chess + 45 kg N compost; subclover + soft chess; resident vegetation + 45 kg N compost; and resident vegetation + 90 kg N ha-1 compost. The compost was variable in nutrient (low N in 2003) and moisture (high in 2005) content and had a chicken manure base in 2002-03 and yard waste in 2004-05. Subclover and soft chess populations remained stable without reseeding while burclover populations peaked in 2004 in the treatments receiving compost. Only the May 13, 2002 soil nitrate-N concentrations were reflected in the July 30 leaf N levels. Subclover treatments showed a trend for higher cover crop dry matter yield and nitrogen content which resulted in tree leaf N levels at 26.7 g kg-1 or higher during the 4 year study. All compost treatments received sodium nitrate in 2004 and 2005 when leaf analysis showed borderline N deficiency (<25 g kg-1) in several plots. The subclover and the 90 kg N ha-1 compost treatments had the most rapidly growing trees: 94.4 and 90.0 cm2 in 2004 and 116.1 and 114.5 cm2 in 2005 respectively. There were no significant differences in yields, fruit size or firmness in 2004-2005; however, more brown rot damage was seen in the treatment receiving the most compost and sodium nitrate. Annualized cost per hectare for double row-middle nutritional treatments ranked from lowest to highest was: subclover + soft chess - $50; subclover - $53, resident vegetation + 45 kg N - $134, soft chess + 45 kg N - $138, and resident vegetation + 90 kg N - $204.
Recorded presentation