Wednesday, November 7, 2007
299-5

Potential for Improved Nutrient Use Efficiency in Florida Sugarcane Production Using Controlled Release Products.

Kelly Morgan, 2686 Sr 29n, University of Florida, University of Florida, Southwest Florida Research and Education Center, Immokalee, FL 34142-9515

Florida leads the nation in sugar production, with annual production on approximately 172,000 ha. The majority of sugarcane is grown on muck soils (Histisols), however, approximately 40,500 ha of sugarcane are grown on sandy soils (Entisols and Spodosols). Sugarcane grown on sandy soils typically under-produce sugarcane grown on muck soils due to the poor water holding and nutrient retention capacity of the sandy soils compared with those of muck soils. A randomized complete block experiment of four fertilizer sources at two rates each was initiated in 2005. The fertilizer sources were 1) standard soluble, 2) controlled release complete fertilizer (CRF), 3) controlled release N with soluble P and K (CRN), and 4) a combination of soluble N and CRN). The soluble fertilizer plots were applied based on 100% and 75% of an N rate of 290 kg ha-1 yr-1. The CRF, CRN, and combination soluble and CRN were applied at 75% and 50% of the 290 kg ha-1. The goals of the study were to demonstrate that the use of CRN or CRF in sugarcane production can 1) reduce annual application costs and annual N application rates, 2) provide adequate N nutrition for growth and carbohydrate accumulation, 3) maintain adequate yields, and 4) improve nutrient use efficiency (NUE). Cane counts per unit row, and leaf N concentration were not significantly different among sources and rates. harvested cane weight, sugar yields, and calculated NUE were significantly greater for the combination soluble fertilizer early in the season followed by CRN treatments compared with CRN and CRF treatments which were significantly greater than the soluble source treatments