4.1 Land Use and Occupation
The following crops predominate in these sections of Watershed were
Pasture, Natural Forest and Coffee. The natural forest, considered the
best vegetation cover, is present in an area corresponding to 21.16% of
the area of this stretch of Rio do Peixe Watershed. Santos et al. (2014)
evaluating a watershed with 11,000 ha, located in Botucatu, in relief
conditions similar to Rio do Peixe watershed, in terms of land use and
occupation found 1,109 ha of natural forest, corresponding to 9.95% of
the watershed area, a situation that corresponds to less than half of
the result found in the present work, showing that in this stretch of
Rio do Peixe Watershed, the forest is more preserved.
As for the pasture area, there is an occupation in the studied section
of 30,472 ha, representing 60.81% of the total area of the Watershed
(Table 1). The results found are similar to those of Lima et al. (2004)
who evaluated 43,228 ha of pasture area in a watershed in Ilha Solteira,
SP, which represents 66.79% of the total area. In this work, one of the
positive examples was the transformation of a property, with
agricultural area, located in Ocauçu city, SP, with a degraded pasture
area of 500 ha. After carrying out this work, these 500 ha were
transformed into an agricultural area with no-tillage system, intended
for annual crops, with rotation: brachiaria straw, soybeans, corn and
wheat in winter (crop change and soil management). A new conservationist
technology that was implemented in the region.
Using the images from the Google Earth® Pro to verify the effectiveness
of the works implanted in the pasture area having an erosive process
(Figure 2A and 2B). Action of agri-environmental adequacy to contain the
erosive processes was implemented and the control of the erosion in the
area was accomplished with the construction of containment basins on
areas with pastures. There was an improvement in the visual aspect of
the area compared to soil conservation, in which case it was proven that
pasture management with the use of containment basins favored the
restoration of the area and the return of potential soil productivity.
Analysing Figures 2C, 2D, 2L, and 2M, it can be seen that the change in
management in coffee culture provided a positive change in the
landscape, inferring that in addition to improving the landscape with
more intense vegetation cover (Figures 2D and 2M), there was an
improvement in potential crop productivity. In the coffee culture, what
contributed to the improvement of the soil conditions was the adequacy
of the crop following the level of the ground and recovery of soil
fertility. The soil conservation techniques applied in this case were
sufficient to control erosive processes.
In Figures 2E and 2G, using the image comparison method, it can be seen
that the agricultural terracing built in the area in question was
efficient in controlling erosion processes at the property. According to
Araújo et al. (2009) the use of appropriate management measures and
erosion mitigating actions, with the recovery of the impacted areas,
there will be an improvement in water quality and control of sediment
production, minimizing silting and consequently, there will be an almost
complete environmental rehabilitation.
The comparison between aerial images from before (T1) and after (T2) was
used to assess the efficiency of the results obtained, a method that was
also used by Bezerra et al. (2012) who evaluated by photocomparation the
vegetation cover and the potential of water in the soil aiming at the
monitoring and recovery of degraded areas, considered that the
photocomparation with the supervised classification allowed to follow
the development of the vegetation cover with grasses, as well as their
relation to soil water potential. According to Menezes et al. (2009)
using remote sensing, it was possible to verify the presence of areas
already affected by inadequate management on areas with degraded
pastures. These authors also highlighted the fact that native vegetation
has been largely converted into pasture. Figures 2K and 2O, show the
mechanical control of erosions with the construction of dams and
terraces that altered the landscape of the place, previously degraded,
into a pasture with productive capacity (Figures 2J and 2N). Figure 2J
shows an old and eroded road that carried sediments to the bed of Rio do
Peixe and which was corrected by building terraces (Figure 2K).
It is important to observe the fact that there are practices focused on
the conservation, which represents a large part of the Rio do Peixe
Watershed section, besides promoting important benefits for soil
conservation, it can be another factor that stimulates the increase in
income for producers, once, with conserved pasture, there is a higher
volume of biomass and, consequently, the possibility of higher animal
density. An example of this statement is the pasture areas recovered
with the adoption of the Integrated Crop-Livestock Systems (LIS), where
the management of these pastures has changed, replacing the grass
variety and providing pasture with good vegetal mass during the dry
periods. This resulted in an occupancy rate of five Animal Units (AUs)
per ha, as evidenced by the evaluation of 10 properties, where there was
an average growth of 31% in the occupancy rate, compared to the
original situation found before carrying out the inspection work. It
corroborates with this information the study of Albernaz & Lima (2007)
who evaluated two sub-watersheds, in Lavras, MG, occupied by pastures,
according to conservationist practices: level planting, terracing,
containment basins, liming maintenance and inferred that at Ribeirão
Santa Cruz sub-watershed (SW) more conservation practices are adopted
than at SW Água Limpa and the exposure of the soil to degradation was
bigger at SW Água Limpa. A similar result was observed by Zolin et al.
(2011) stating that the biggest relative reductions in soil loss
occurred on scenarios with conserved pasture, indicating that the
optimization of soil conservation can be accomplished by adopting
conservationist management practices for pasture recovery. According to
Rodrigues et al. (2015) who analysed the role of vegetation in water
interception and erosion control, at Rio Paraíso Watershed, in São
Manuel, SP, and the uncovered soil showed a 98.09% increase in sediment
production, when compared to soils with vegetation cover.