Long-term non-sustainable soil erosion rates and soil compaction in drip-irrigated citrus plantation in Eastern Iberian Peninsula

Artemi Cerdà; Agata Novara; Ehsan Moradi

doi:10.1016/j.scitotenv.2021.147549

Long-term non-sustainable soil erosion rates and soil compaction in drip-irrigated citrus plantation in Eastern Iberian Peninsula

Sci Total Environ. 2021 Sep 15:787:147549. doi: 10.1016/j.scitotenv.2021.147549. Epub 2021 May 7.

Authors

Artemi Cerdà¹, Agata Novara², Ehsan Moradi³

Affiliations

¹ Soil Erosion and Degradation Research Group, Department of Geography, Valencia University, Blasco Ibàñez, 28, 46010 Valencia, Spain. Electronic address: artemio.cerda@uv.es.
² Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, 90128 Palermo, Italy. Electronic address: agata.novara@unipa.it.
³ Department of Reclamation of Arid and Mountainous Regions, University of Tehran, Karaj 31585-3314, Iran. Electronic address: ehsan_moradi13@ut.ac.ir.

PMID: 33992950
DOI: 10.1016/j.scitotenv.2021.147549

Abstract

Agriculture is known to commonly cause soil degradation. In the Mediterranean, soil erosion is widespread due to the millennia-old farming, and new drip-irrigated plantations on slopes, such as the citrus ones, accelerate the process of soil degradation. Until now, the published data about soil erosion in citrus orchards is based on short-term measurements. Long-term soil erosion measurements are needed to assess the sustainability of drip-irrigated citrus production and to design new strategies to control high soil erosion rates. The objective of this study is to assess long-term soil erosion rates in citrus plantations and report the changes in soil bulk density as indicators of land degradation. We applied ISUM (Improved Stock-Unearthing Method) to 67 paired trees in an inter-row of 134 m (802 m² plot) with 4080 measurements to determine the changes in soil topography from the plantation (2007) till 2020. Soil core samples (469) were collected (0-6 cm depth) to determine the soil bulk density at the time of plantation (2007) and in 2020. The results demonstrate an increase in soil bulk density from 1.05 g cm^-3 to 1.33 g cm^-3. Changes in soil bulk density were higher in the center of the row as a result of compaction due to passing machinery. Soil erosion was calculated to be 180 Mg ha^-1 y^-1 due to a mean soil lowering of 1.5 cm yearly. The highest soil losses were found in the center of the inter-row and the lowest underneath the trees. The extreme soil erosion rates measured in new drip-irrigated citrus plantations are due to soil lowering in the center of the inter-row and in the lower inter-row position where the incision reached 80 cm in 13 years. The whole field showed a lowering of the soil topography due to extreme soil erosion and no net sedimentation within the plantation. The results show the urgent need for soil erosion control strategies to avoid soil degradation, loss of crop production, and damages to off-site infrastructures.

Keywords: Citrus; Drip irrigation; Glyphosate; ISUM; Management; Mediterranean; Soil; Sustainability.