Catchment scale hydrology of an irrigated cropping system under soil conservation practices

Abstract

Soil erosion by water is a pressing environmental problem caused and suffered by agriculture in Mediterranean environments. Soil conservation practices can contribute to alleviating this problem. The aim of this study is to gain more profound knowledge of the effects of conservation practices on soil losses by linking crop management and soil status to runoff and sediment losses measured at the outlet of a catchment during seven years. The catchment has 27.42 ha and is located in a commercial farm in southern Spain, where a package of soil conservation practices is an essential component of the farming system. The catchment is devoted to irrigated annual crops with maize–cotton–wheat as the primary rotation. Mean annual rainfall‐induced runoff coefficient was 0.14 and mean annual soil loss was 2.4 Mg ha−1 y−1. Irrigation contributed to 40% of the crop water supply, but the amount of runoff and sediment yield that it generated was negligible. A Principal Components Analysis showed that total soil loss is determined by the magnitude of the event (rainfall and runoff depths, duration) and by factors related to the aggressiveness of the events (rainfall intensity and preceding soil moisture). A third component showed the importance of crop coverage to reduce sediment losses. Cover crops grown during autumn and early winter and crop residues protecting the soil surface enhanced soil conservation notably. The role of irrigation to facilitate growing cover crops in Mediterranean environments is discussed. Copyright © 2016 John Wiley & Sons, Ltd.

Direct and indirect effects of rainfall and vegetation coverage on runoff, soil loss, and nutrient loss in a semi‐humid climate

“…Rainfall strongly affects runoff, sediment, and nutrient loss (Ferreira et al, 2018), and soil nutrients are partially attached to soil particles and partially dissolved in water and lost by runoff (Kato et al, 2009; Shi et al, 2018). Runoff, soil erosion, and soil nutrient loss are complex processes controlled by various factors (Guo et al, 2010), such as precipitation, soil physical and chemical properties, soil moisture content, vegetation cover, and tillage measures (An et al, 2013; Cid et al, 2016; Kurothe et al, 2014; Mutema et al, 2015). Various models have been constructed to calculate and predict soil nutrient losses (Shi et al, 2018; Zhou et al, 2019).…”