The influx of sediments carried by rivers can be measured continuously using a turbidimeter through the indirect relationship between turbidity and suspended sediment concentration (SSC). However, this process is dependent on obtaining water samples with suspended sediments to calibrate the turbidimeter. Sampling can be carried out through different methods, resulting in errors and uncertainties in estimating the SSC. Four different possibilities for the composition of the calibration curve were tested in order to evaluate the effectiveness of the turbidimeter calibration for different sampling strategies. The study was conducted in 2012 and 2013 in two catchments in southern Brazil that had a strong sediment yield impact. The results indicate that sampling during rainfall events generate a significant and representative SSC for the turbidimeter calibration. The use of an integrating sampler for synthetic samples provides an effective calibration, but overestimates SSC compared to calibration from rainfall event sampling. The samples collected at fixed intervals - weekly and daily - generated an insufficient amount of data and are not representative of real sediment concentrations of the catchments.

Extreme weather events, such as heavy rains and droughts, necessitate the rapid adaptation of production systems to prevent the degradation of natural resources and to maximize production potential. Defining adaptive practices requires an in-depth understanding of the factors that control the formation and propagation of surface runoff and the identification of specific practices tailored to each location. No-till system, coupled with complementary storm runoff management practices, is effective in controlling surface runoff and related processes. However, the planning of the capacity and allocation of these practices, considering the specific interaction of controlling factors in each catchment, is not well understood. Planning conservation practices at the catchment scale through hydrological modeling and monitoring presents an efficient alternative, as it integrates the controlling factors that govern storm runoff dynamics. This study sought to understand the influence of different levels of conservation intervention (surface runoff control practices) on the hydrological behavior of the experimental catchment of the Guarda Mor River (southern Brazil). The method relied on monitoring hydrological variables (rainfall and streamflow) at the catchment outlet and on the physiographic characterization of the catchment, including the spatial variability of soils, topography, land use, and soil management. After analyzing a significant set of rainfall-runoff events, the generation and propagation of surface runoff were modeled (calibration and validation) using the Limburg Soil Erosion Model. The impacts of two conservation intervention scenarios were tested: buffer strips plus well-managed no-till (Scenario 1) and retention broad-based terraces plus well-managed no-till (Scenario 2). Conservation practices were assessed by evaluating the following hydrologic parameters: surface runoff volume, peak flow, and time to peak. Simulation results indicate that both intervention levels effectively controlled surface runoff. Scenario 1 resulted in an average reduction in surface runoff volume and peak flow attenuation of 7 and 6 %, respectively. Scenario 2 achieved an average decrease in surface runoff volume and peak flow attenuation of 30 and 28 %, respectively. These results quantitatively demonstrate the positive impact of soil and water conservation practices on the drainage network. The impacts of the two scenarios in the time to peak were not significantly altered, except for one event. Catchment-scale conservation planning is an efficient and promising strategy for improving conservation agriculture, underscoring its importance in water resource management and promoting environmental services.

Strategies to mitigate degradation and ensure food and water security are among the main challenges in agricultural development. Unconsolidated information about the positive impact of conservationist practices on productivity increase is fundamental for their adoption by farmers. This study evaluated if the saved rainfall excess in catchment with terrace generates higher soybean and corn yield due to greater water availability in the crop rooting zone. Experiments were conducted in southern Brazil during the agricultural years of 2016/17 (soybean) and [...] ABSTRACT Strategies to mitigate degradation and ensure food and water security are among the main challenges in agricultural development. Unconsolidated information about the positive impact of conservationist practices on productivity increase is fundamental for their adoption by farmers. This study evaluated if the saved rainfall excess in catchment with terrace generates higher soybean and corn yield due to greater water availability in the crop rooting zone. Experiments were conducted in southern Brazil during the agricultural years of 2016/17 (soybean) and