4.1. Effects of land use on TSS leaching and inorganic nutrient
concentrations
In recent years, watershed modelers have put increasing emphasis on
simulating internal watershed processes as realistically as possible
(Nasirzadehdizaji et al., 2022; Senent-Aparicio et al., 2021). For the
correct diagnosis of agricultural production in hilly terrain, the
prediction of erosion losses is crucial ( Basha et al., 2015;
Smoroń et al., 2009), and water quality can be improved by using the
catchment area effectively (Abeysingha et al., 2015; Bedla and Król
2014; Louis et al., 2011). A large effect on erosion is related to the
way the adjacent area has been used and developed. In forest areas in
small mountain catchments, land changes are less pronounced (Woo et al.,
2021).
SAR has revealed the specific associations between adjacent areas and
water indicators. For instance, permanent grasslands limit the supply of
weathered material, and there is a linear relationship between permanent
grassland and the leaching of N-NH4+in the Smugawka stream (Table 5). Since forests slow soil erosion, they
are an important source of protection against water erosion (Stępniewski
et al., 2010). Additionally, the adopted methods for assessing the
intensity of water erosion are influenced by modern morphogenetic
processes, and the physiographic features of the catchment area play a
major role in determining soil losses (Halecki et al., 2018 a).
The leaching effect of inorganic nutrients can also be limited by
increased vegetation. The SAR results revealed that the area covered by
permanent grasslands exhibited the lowest inorganic nutrient losses
(Fig. 6). Moreover, despite low concentrations of the inorganic
nutrients in the tributaries, their concentrations in the main stream
gradually increases (Fig. 7).