Banca de QUALIFICAÇÃO: MILA FAÇANHA GOMES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MILA FAÇANHA GOMES
DATE: 27/11/2023
TIME: 14:00
LOCAL: Online, via Google Meet (meet.google.com/umw-rdmp-and)
TITLE:

SOIL HEALTH INDICATORS IN OIL PALM  AGROFORESTRY SYSTEMS IN THE EASTERN AMAZON

KEY WORDS:

soil quality, labile soil carbon, degraded soil.

PAGES: 115
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Manejo e Conservação do Solo
SUMMARY:

Agroforestry systems (AFSs) in general are recognized for promoting improved health and increased soil carbon (C) stock.  In the Amazon region, AFSs with oil palm have been cultivated as a productive strategy and to recover degraded areas.  The objective of this study was to evaluate whether management practices adopted in AFSs with oil palm affect health indicators and soil C stock.  In the first chapter, we evaluated two SAFs with oil palm that differ in the level of species diversity: higher diversity (AFS-B) and lower diversity (AFS-A).  We use a regenerating forest (Forest) as a comparison, as it is also a model of environmental recovery.  In layers 0-10, 10-20 and 20-30 cm of the soil, we evaluate chemical indicators: active acidity (pH), calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), aluminum (Al );  (b) physical indicators: density (DS) and aggregate stability (AGREG) and;  (c) biological indicators: carbon oxidizable by permanganate (CPOX), particulate organic carbon (COP), total soil carbon (SOC content) and root stock (ROOT).  Additionally, we assessed the total soil carbon stock (SOC stock).  The values of biological indicators in the most superficial layer, especially C indicators, were higher in the AFSs than in the forest;  we found the same pattern (AFSs>Forest) for chemical indicators.  The physical indicators did not show a specific pattern of variation between SAFs and forest;  aggregate stability was higher in forest than in AFSs in all soil layers and soil density was higher in AFS-Band FOR compared to AFS-A in the most subsurface layer.  Therefore, oil palm AFSs improve the chemical and biological health of the soil, especially in the upper layers, but do not improve the physical health of the soil.  In the second chapter, we evaluate the activity of the enzymes Betaglucosidase (Beta) and Arylsulfatase (Aryl), CPOX, microbial respiration (RM), soil organic matter (SOM) and COT in three soil cover systems (AFS with oil palm, oil palm monoculture and forest) and in the management zones of oil palm production systems (harvest path-CAR, weeded circle-ACP, leaf pile-PIL and diversified strip-DIV).  We found better levels of these soil health indicators in AFSs compared to forest and monoculture;  and higher levels in PIL, intermediate in DIV and ACP and lower in CAR.  Our results for COT, Beta, Aryl and CPOX indicate that oil palm agroforestry systems promote better soil health compared to monoculture and forest.  These indicators show that management zones with greater C input (PIL, DIV and ACP) have better soil health.  In most comparisons, Beta, Aryl, CPOX and COT were more sensitive than RM and MOS to differentiate land cover systems and management zones.  In the third chapter, we evaluate the increase in CPOX and COT between 2018 and 2022 in AFSs with oil palm, oil palm monoculture and forest;  and in the CAR, ACP, PIL and DIV management zones.  Our results for CPOX and COT show that AFSs with oil palm have a greater increase in soil health in the short term compared to monoculture.  AFSs also tended to improve soil health status in relation to more ecologically stable areas, in this study, the forest.  In relation to the management zones, the AFS zones showed an increase in CPOX and TOC, unlike monoculture, whose soil health in the management zones did not change or decreased.  In general, CPOX was more sensitive to identify differences in soil health increases across land cover systems and management zones.  The association of organic fertilization with species diversity in AFSs was mainly responsible for the short-term increase in soil health in this system compared to monoculture.  Despite the positive results for AFSs, more research is needed to assess long-term changes in soil health in these cropping systems, as the oil palm planting cycle lasts approximately 25 years.  However, our results suggest that oil palm cultivation in AFSs can be a more sustainable alternative than monoculture and has great potential to increase soil health.

BANKING MEMBERS:
Presidente - 013.474.077-74 - STEEL SILVA VASCONCELOS - UFRA
Externa ao Programa - 1741065 - VANIA SILVA DE MELO
Externa à Instituição - LEIDIVAN ALMEIDA FRAZÃO
Externa à Instituição - IÊDA DE CARVALHO MENDES
Externa à Instituição - PATRÍCIA ANJOS BITTENCOURT BARRETO-GARCIA