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Biomass and nutrients accumulation in sugarcane as related to nitrogen fertilizer sources

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Author(s):
José Marcos Leite
Total Authors: 1
Document type: Master's Dissertation
Press: Piracicaba.
Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
Defense date:
Examining board members:
Paulo Cesar Ocheuze Trivelin; Jose Carlos Polidoro; Rogério Peres Soratto
Advisor: Paulo Cesar Ocheuze Trivelin
Abstract

The transition of burnt to unburnt sugarcane management difficult the fertilizer management (especially in relation to nitrogen, N) due to the greater immobilization of N-fertilizer applied over the straw and high N-NH3 volatilization losses since ureia is the main N source. The objective of this study was to evaluate the rate of biomass and nutrients accumulation by sugarcane, as well the stalk yield as related do N-fertilizer sources, in the ratoon sugarcane cycle. Two trials were set up on aTypic Eutrustox (TE) and on a Typic Haplustox (TH), both in Sao Paulo State, Brazil. The treatments consisted of 100 kg N ha-1 applied by means of the the following N sources: ammonium chloride-AC, ammonium nitrate-AN, urea-U, Ajifer®, NitromagTM and ammonium sulfate- AS, and an additional treatment without N. Four measurements were performed throughout the crop cycle. The sugarcane showed three phases of vegetative growth, regardless of treatment. At TE soil the NitromagTM promoted higher biomass accumulation, reaching 45 Mg ha-1 and 110 Mg ha-1 stalk fresh, while at TH soil the Ajifer® increased the biomass as compared to the other sources, reaching 30 Mg ha- 1. The highest rate of biomass accumulation occurred around 220 days after harvest , reaching 350 kg ha-1 day-1 in treatments with NitromagTM and AN. . The N addition increased sugarcane biomass accumulation, and N accumulation occurred before biomass accumulation. . The average order of nutrients extraction by sugarcane was K> N> Ca> S> Mg> P, with 23, 50, 32, 56, 53, 53% (at TE soil) or 76, 46, 21, 56, 37, 57% (at TH soil) of those nutrients being accumulated on the stalks. The nutritional requirement of sugarcane was 1.45, 0.14, 2.44, 0.61, 0.26 and 0.33 kg t-1 of stalks (fresh weight), respectively for N, P, K, Ca, Mg and S. The soil content of K, Ca, Mg and S directly affected the nutrients accumulation by sugarcace, increasing the extraction and exportation of nutrients. (AU)

FAPESP's process: 09/12537-3 - Fitomass and nutrients accumulation in sugar cane ratoon related to nitrogen sources in unburned harvesting system
Grantee:José Marcos Leite
Support Opportunities: Scholarships in Brazil - Master