| dc.description.abstract | The Integrated agricultural production systems are seen as viable alternatives to sustainable land use.
This work aimed to evaluate the microbiological attributes and the humic fractions of soil organic matter in
areas submitted to different systems of land use and management in the city of Curvelo - MG. This work
was conducted at Fazenda Experimental do Moura da Universidade Federal dos Vales Jequitinhonha e
Mucuri, UFVJM (Experimental Farm of Moura, Federal University of Jequitinhonha and Mucuri Valleys -
UFVJM), located in the city of Curvelo, in the State of Minas Gerais. Seven systems of use were selected:
three crop-livestock-forest integration systems, with crop variations among Eucalyptus urograndis, maize,
marandu grass and java; Monocultures of java (JAVA) and marandu grass (MAR); consortium between
java and maradu grass (J + M) and low productivity pasture (PAST). The soil samples were collected in
winter (July 2015) and summer (January 2016) at three depths to determine microbial biomass carbon
(C-BMS), basal respiration (C-CO2), and the microbial metabolic quocient of soil. For the fractionation of
SHs in humic fraction (HUM), humic acid fraction (FAH) and fulvic acid fraction (FAF), samples were
collected only in summer (January 2016) at the three depths. The FAH / FAF ratio and the relation
between the alkaline extract (FAF + FAH) and the HUM (EA / HUM) were calculated. Soil microbiological
attributes were more influenced by the time of year than by the management systems. The carbon in the
microbial biomass varied between 79 and 598 mg kg-1 of soil and the microbial quotient between 0.40 and
2.84%, being these values higher in the rainy period. The metabolic quotient ranged from 0.18 to 2.03
and was lower in the same period, indicating that the microorganisms spent less energy by using the
available substrate, incorporating more C to their biomass. The basal respiration of the soil did not differ
for the two seasons, with the exception of the MAR that presented smaller averages for the dry period. In
the dry period, for the depth of 5-10 cm, the ILPF-J presented a C-BMS value of 222 mg kg-1 of soil
superior to those found in monocultures and in PAST. The highest values of TOC and NT and C of the
humic fractions were found in the VN. The FAF decreased in deeper layers of the soil, mainly in the VN,
being a very soluble fraction in the soil. The values of FAH / FAF ratio above 1.0 showed the
predominance of FAH fraction in relation to FAF, a result attributed to intense humification of MOS. The
HUM fraction was higher than the other fractions in all evaluated depths, and the low values of the EA /
HUM ratio indicate higher recalcitrance of the MOS in the evaluated systems. The ILPF-M system
presented an increase in NT and C-HUM content in relation to PAST, and these results are related to the
degree of degradation that the pasture is, contributing with less amount of plant material to the soil. As
the VN is an environment in dynamic equilibrium, the environment presented better soil quality (QS) when
compared to the other treatments. However, the integrated production systems (ILPF and ILP) presented
improvements in QS in relation to low yield pasture and may be indicated for the recovery of degraded
soils. | |
