Effects of Nitrogen Fertilization and Seed Piece Applied Fungicides on Establishment, Tiller Dynamics, and Sucrose Yields in Successively Planted Sugarcane

Abstract

Sugarcane (Saccharum spp.) successive planting causes 25–30% yield reduction in comparison to fallow or rice rotation planting in a three-year production cycle on Florida Histosols. Field experiments were established to manage the yield losses associated with successive planting through nitrogen fertilization and seed piece application of fungicides in plant and first ratoon crops each at two sites. Nitrogen fertilization treatments included 0 (N0), 50 (N50), and 100 (N100) kg ha−1 applied in furrows at the time of planting, and one split application (N50+50) with 50 kg ha−1 applied at planting and 50 kg ha−1 applied at 90 days after planting as side-dress. Fungicides treatments were mancozeb at 2.5 kg a.i. (active ingredient) ha−1, mefenoxam at 0.57 kg a.i. ha−1, and azoxystrobin at 0.30 kg a.i. ha−1 applied to seed cane pieces laid in the furrows at planting. Nitrogen fertilization showed increasing trends of the tiller and millable stalks production in plant and ratoon crops. N response varied with the time of ratooning. Overall, N50+50 produced greater tons of cane per hectare (TCH) and tons of sucrose per hectare (TSH) compared to other N treatments in plant crop and late season ratoon crop (ratooned in March). N100 treatment enhanced tillering and TCH in December ratooned crop. In 2016 plant crop, mefenoxam produced higher TCH than others, but no carryover effects were observed in ratoon crops. Both nitrogen fertilization and fungicides seem to be promising cultural practices to minimize yield losses in successive sugarcane planting in Histosols.