This special issue does not cover all aspects addressed on the ERB 2018 conference as the topic includes a diversity of issues. Rather it focuses on specific aspects. Four papers were accepted and are published in this volume. The topics reported in this volume cover studies in small hydrological basins considering the heterogeneity of the respective landscape characteristics and agricultural practices. All analyses demonstrate the explicit need for long-term monitoring with high spatial and temporal resolution for process analyses and further strategy planning. A summary of each paper is given in the following.

Bauwe et al. (2019) used the ecohydrological model SWAT (Soil and Water Assessment Tool) to predict streamflow, nitrate loadings and crop yields in a small German agricultural basin (167 ha). Daily streamflow and nitrate data, annual crop yield values and detailed field maps helped to implement exact crop rotations and nitrogen fertilization into the model. From the results of a scenario analysis it was concluded that a slight decrease of nitrogen fertilization leads to significant reductions in nitrate loadings, whereas crop yields remained on a high level. The study outcomes could be used for an economically and ecologically optimal nitrogen management.

Fiener et al. (2019) presented the methodological requirements in measuring soil erosion and runoff from small experimental basins. Therefore, they used a dataset of eight years of monitoring in 14 adjacent small basins (0.8 to 13.7 ha) under soil conservation at Scheyern in Germany. As surface runoff and sediment delivery is controlled by highly dynamic spatial and temporal field conditions, their analyses show that rare extreme events led to the major amount of sediment delivery. They highlight that a quantification of these relationships is only possible by sufficiently long monitoring time series.

Application of crop residues (mulch) over the soil surface is a common practice to control soil erosion and promote infiltration. The paper of de Lima et al. (2019) aimed at investigating the effect of different rice straw mulch sizes on runoff and sediment transport. The results of this laboratory study are a contribution to the better understanding of the soil loss process in small areas/basins and to the definition of relevant soil conservation measures, at the plot/field scale.

Montenegro et al. (2019) presented an assessment of near surface soil moisture spatial-temporal distribution and of the impact of soil conservation techniques in reducing runoff and soil loss, using small-scale experimental plots in a representative small basin located in Alto Ipanema River Basin of the Pernambuco State, Brazil. Soil and water monitoring was performed in plots with different soil cover conditions (bare soil plots; plots with natural cover – Caatinga biome vegetation; plots with cactus palma barriers; and plots with dry grass mulch cover), where soil moisture probes were installed. Caatinga was highly effective in terms of soil and water conservation at the small basin scale for both the dry and the wet season, resulting in a positive nexus between vegetation and water availability. The cactus barriers and grass mulching were both effective for soil moisture conservation and for runoff reduction.

This article is part of the special issue “Innovative monitoring techniques and modelling approaches for analysing hydrological processes in small basins”. It is a result of the 17th Biennial Conference ERB 2018, Darmstadt, Germany, 11–14 September 2018.