Assessment of microorganisms dynamics in sugarcane IAC (93-3046) plants

Author(s)

Sérgio Gil de Toledo Filho

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2010-10-01

Examining board members

Luiz Gustavo Nussio; Clóves Cabreira Jobim; Wilson Roberto Soares Mattos

• Advisor: Luiz Gustavo Nussio

Abstract

The numbe of microbial species in forages during the ensiling is responsible for the silage fermentation, and the numbeof colony forming units (cfu) changes during the crop cycle and environmental conditions. It suggests that the initial microbial profile strongly influences the effectiveness of additives used in the process. In this context, we propose three trials to characterize the microbial population in plants of sugarcane. The first trial evaluated the microbial population in plants of sugarcane by the technique of pour plating. The treatment consisted of two levels of fertilization (NPK and NPK associated with solid manure - 120kg N / ha) applied immediately after sugarcane was harvested by hand. The objective was quantify the number of lactic acid bacteria, yeasts and molds, as well as relating their frequencies with environmental effects, fertilization and stage of maturation, with samples taken at 10, 12, 14 and 18 months, corresponding to the months of March, May, July and November 2009. The second trial measured the biometric variables, morphological, the accumulation of dry matter and nutrients in sugarcane subjected the sources of fertilization, as mensioned. The third trial performed chemical assessments of sugarcane subjected to the sources of fertilization. The trials consisted of a completely randomized design with six blocks sub-divided into two plots. Data were analyzed by the procedure Proc Mixed and Proc NLIN of SAS program. There was no effect of treatment in any trial. The fresh yield ranged from 162 to 188tGM/ha which can be considered high. The number of green leaves was increased from 9.5 to 10 to 10 to 18, which is expected, since there is an increase of plant biomass across the time. The same was observed for dead leaves, from about 0 leaves per plant up to 3 leaves. The weight of the leaves was also increased. The weight and length of the stem increased from March to May, and became more intensive from July with increasing rainfall. However, during the dry season (May - July) there was a decreased growing rate.The sugarcane oBrix was 10 at 10 months, 17 oBrix at 12 months and 20oBrix to 20 months. The maturity index increased, from 33.46 to 10 months reaching 88.5 at 18 months. At 12 months the sugarcane showed dry matter content of 24% and 28% at 18 month. The NDF and ADF of the whole plant decreased over time from 10 months (61% and 38.4% NDF and ADF, respectively) for 12 months and remained constant until 18 months (55% and 35 6% NDF and ADF, respectively). A is positive correlation between IVDMD and oBrix was observed, and the equation, IVDMD = 41.35 + oBrix, with R2 = 0.73 and P <0.01 is an important tool to estimate IVDMD. Over time, the counts of lactic acid bacteria were increased. In general, all plant fractions showed similar counts, starting from 4 log cfu/gGM to 10 months and reaching about 5.5 log cfu/gGM to 18 months. At 10 months the whole plant sugarcane had yeast count of 4 log cfu/gGM remaining constant until 18 months, when it reached 5.7 log cfu / g MV. The source of fertilizer, whether chemical or organic, does not interfere in the population of microorganisms, however, varies depending on the experimental period and climatic conditions. (AU)

• FAPESP's process: 08/02365-8 - Evaluation of population dynamics of microorganisms in silage and plants of sugar cane (IAC 93-3046)
• Grantee: Sérgio Gil de Toledo Filho
• Support Opportunities: Scholarships in Brazil - Master