Banca de DEFESA: IARA MARIA LOPES RANGEL

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : IARA MARIA LOPES RANGEL
DATA : 18/06/2018
HORA: 09:00
LOCAL: Sala 39 do Departamento de Solos - IA
TÍTULO:

The removal of part of the sugarcane straw for bioenergy production or second generation alcohol can generate an even more positive energy balance in the sugarcane industry

PALAVRAS-CHAVES:

Saccharum spp. Straw Removal. Soil Attributes. Greenhouse gases.

PÁGINAS: 110
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Ciência do Solo
ESPECIALIDADE: Manejo e Conservação do Solo
RESUMO:

The removal of part of the sugarcane straw for bioenergy production or second generation alcohol can generate an even more positive energy balance in the sugarcane industry. However, the maintenance of sugarcane straw on the soil surface generally contributes to the maintenance of soil quality and stem yield. Thus, the amount that can be withdrawn from the system without causing damage to soil attributes and crop productivity over time is uncertain. Thus, the objective of this study is to propose a sustainable management of sugarcane harvest for the southern and southeastern regions of the country, more specifically, to make recommendations on how much of the straw should be left on the soil surface and how much can be withdrawn for the co-generation of energy or second-generation alcohol manufacture causing the least possible harm to soil safety. For this, two experiments were conducted in distinct regions of the country: Colorado-PR (Southern region) in Oxisol under alternating double planting spacing (0.9 x 1.5 m), and in Linhares-ES (Southeast region) under Ultisol in single spacing (1.5 m). Four levels of straw deposition (0, 25, 50 and 100%) were evaluated. Soil samples were collected in two distinct moments: right after the 1st and 2nd soca harvest. The soil samples were collected in the 0-5, 5-10, 10-20 and 20-40 cm layers for determination

of C, N, pH, H + Al, Al, Ca, Mg, Na, K , P, densimetric physical fractionation (layers 0-5 and 5-10 cm) and stability of aggregates (layer 0-10 cm) and in the second moment in the layers of 0-5, 5-10, 10-20 and 20-30 , 30-40, 40-60, 60-80 and 80-100 cm for the same determinations of the first year plus determination of soil density and porosity. Static chambers and Pitfall traps were installed at these two times for collection of nitrous oxide and epigeonic invertebrate fauna, respectively. Plant samples were collected to determine the yield of thatch and straw. Total straw removal (0%) is detrimental to soil quality reflecting negatively on shoot yield in both producing regions. However, the impacts caused by straw levels are distinct across regions. In the southern region, the maintenance of 50% of straw (7.55 Mg ha-1 year-1) positively influences the contribution of free light fraction, C, N, soil physical attributes and stem yield. However, the maintenance of 100% straw results in higher accumulated emission of N2O from the soil and provides conditions favorable to soil compaction. For the Southeast region the best level was 100% straw (9.2 Mg ha-1 year-1 ), which presented better values of C, N, chemical, physical and biological attributes of the soil, as well as higher yield of stems. However, total straw removal (0%) was the condition that favored the largest N2O flows in the Southeast region. The results suggest that the ideal straw

level to be maintained in the field depends on the specific growing conditions of each region, which prevents a single recommendation for the whole of Brazil. However, it is recommended to monitor the effect of different straw levels on soil quality, greenhouse gas emissions and yield of stems over time to more accurately define the minimum amount of straw that ensures a system production of sugar cane in each growing region.

MEMBROS DA BANCA:
Externo à Instituição - DAVID VILAS BOAS DE CAMPOS - EMBRAPA
Interno - 386715 - EDUARDO LIMA
Externo à Instituição - HEROLDO WEBER - UFPR
Externo ao Programa - 1282206 - JULIANO BAHIENSE STAFANATO
Externo ao Programa - 2136627 - NIVALDO SCHULTZ