Physical assessment of a Mollisol under agroecological managements at Quillota valley. Mediterranean Central Chile

Manuel Casanova,Berthin Ticona,Gonzalo Ávila,Carlo Sabaini,Osvaldo Salazar,Oscar Seguel,Marco Pfeiffer,Yasna Tapia,Eduardo Gratacós

doi:10.7764/ijanr.v47i3.2290

Abstract

A number of agroecological practices have been proposed for assessing soil quality. Several physical soil properties have been shown to be important for determining soil quality by using the sustainability index (SI) and the cumulative rating approach. The main aim of the study was to determine the effects of different agroecological managements on the physical properties of a Mollisol in the Mediterranean central Chile. In addition, some physical properties were selected to compare the soil quality among different agroecological management practices and highly mechanized intensive systems by using the SI and cumulative rating approaches. An experimental field was defined in an area of 3.5 ha in 2014. Four sites with different agroecological practices were selected in 2019 to assess soil physical properties: rainfed Mediterranean annual prairie - no tillage (1-S), irrigated perennial prairie with deep-root species - no tillage (2-N), irrigated annual and perennial prairie - conventional tillage (4-S), irrigated vegetables and flowers - minimum tillage (4-N); an avocado orchard with traditional management was used as the control. Soil organic carbon and the following soil physical properties were selected to assess SI and CR: bulk density, total porosity, void ratio, air capacity, fast-drainage pores, relative field capacity, hydraulic conductivity, structural stability index and unavailable water pores. The applicability of the selected physical indicators to the SIs of agroecological management practices compared with the control was demonstrated. The cumulative rating index (CR) for each land use showed that all agroecological practices constituted sustainable soil management (25≤CR<30), whereas the avocado orchard showed the least sustainable management (30≤CR<40), and a change in soil use is recommended.

Highlights

All Mediterranean-type zones worldwide appear to be hotspots of climate change and dwindling biodiversity (Myers et al, 2000; García et al, 2011)
This scenario of vulnerability is described by Aguilera et al (2020), who urged the rapid adoption of systemic measures to increase the resilience of production systems and precision agroecological practices with high adaptation potential through the generation of local knowledge based on the integration of scientific and traditional ecological knowledge
A positive, significant correlation of bulk density (Bd), as determined from cylinders and clods, was observed with sand contents but the correlation was negative with soil clay and silt contents (Supplemental Material 3)

Summary

Introduction

All Mediterranean-type zones worldwide appear to be hotspots of climate change and dwindling biodiversity (Myers et al, 2000; García et al, 2011). As in other Mediterranean zones, agriculture in central Chile is currently conducted under vulnerable conditions and is characterized by different forms of soil degradation (e.g., soil organic matter decline), water scarcity or overuse, disrupted nutrient cycles, land use change, high dependence on biomass and energy imports, and a prevalence of highly specialized and low-diversity agroecosystems This scenario of vulnerability is described by Aguilera et al (2020), who urged the rapid adoption of systemic measures to increase the resilience of production systems and precision agroecological practices with high adaptation potential through the generation of local knowledge based on the integration of scientific and traditional ecological knowledge. Ryan and Peigné (2017) concluded that agroecology, as a scientific discipline, will help facilitate efforts to respond to the actual challenges of agricultural production due to of increasingly applied systems thinking and interdisciplinary research approaches

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