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Beya-Marshall, V., Arcos, E., Seguel, O., Galleguillos, M., & Kremer, C. (2022). Optimal irrigation management for avocado (cv. 'Hass') trees by monitoring soil water content and plant water status. Agric. Water Manag., 271, 107794.
Abstract: Irrigation scheduling based on soil water content (Ow) sensors requires that Ow be maintained within a range (management lines) that is optimal for plant growth. The lower limit or “breaking point ” is determined following the soil water content dynamics on the transition of a rapid rate of depletion to a slower, under similar reference evapotranspiration. Although this criterion is practical, its implementation should be validated with plant water status measurement that contemplate weather condition, such as stem water potential “non-stressed ” baseline (Tx as a function of vapor-pressure deficit (VPD) in Ow conditions that do not limit yield). A study was con-ducted on a mature cv. 'Hass' avocado orchard in Central Chile during two seasons. There were 5 irrigation treatments: T1, Control; T2 and T3 with 29% less and 25% more of what was applied in T1, respectively; T4 and T5 same as Control until first and second fruit drop abscission, respectively, and then with 29% less. T1 trees were irrigated using a continuous frequency domain reflectometry (FDR) probe to maintain the root zone be-tween field capacity and the breaking point. There was biweekly monitoring of the Ow prior to irrigation, Tx and VPD. The Tx decline proportional to the intensity and the timing of water restriction; however, no treatment affected the crop load in either season. T2 did not show significant detrimental in fruit size, production and maturation, despite that frequently reached water content levels at the limit of the breaking point, and showed lower levels of stem water potential than Control, being the treatment with the highest water productivity. The results confirm that breaking point is an effective criterion to establish irrigation management. Additionally, when comparing the baseline for our non-stressed trees with a baseline from full irrigation treatments obtained from the literature, 30% water savings were achieved.
Keywords: Water productivity; Stem water potential; Baseline; Frequency domain reflectometry; Irrigation scheduling; Yield; Water scarcity
Salazar, O., Casanova, M., Fuentes, J. P., Galleguillos, M., Najera, F., Perez-Quezada, J., et al. (2022). Soil research, management, and policy priorities in Chile. Geoderma Reg., 29, e00502.
Abstract: Soils of Chile
Given the diversity of soil types in Chile, soil scientists face complex challenges to prioritize across different regions. Chile is located at the southwestern extreme of South America and is characterized by its well-marked latitudinal climate segmentation along 4300 km from 18◦ S to 56◦ S, spanning diverse transversal geomorphologic units across a narrow 180-km wide landscape from the Andes mountains, Andean foothills, Central Valley, and Coastal Range to the coastal plains. Chilean soils formed in geographic isolation flanked by the Pacific Ocean, Atacama Desert and the Andes mountains (Casanova et al., 2013). From the extreme hyperarid north to central Mediterranean Chile, Aridisols and Entisols dominate, with Histosols in only a few areas of the northern Altiplano highlands. Residual and colluvial soils coexist with soils derived from volcanic ashes, which in the temperate and rainy southcentral Chile allow Andisols to develop. Alluvial, glacial and fluvioglacial soils occur primarily along the Central Valley and southern Patagonia plains. The southern volcanic zones of the Andes influence
central-southern Chile, which is dominated from 35◦ S to 49◦ S by soils
derived from volcanic ashes, mainly Andisols and Ultisols, where about 70% of agricultural activities are carried out. All remaining Soil Taxonomy Orders are also found, except Oxisols. Quantitative and qualitative anthropogenic soil degradation due to land use change and agricultural management has been an old and serious problem in Chile as far back as the mid-eighteenth century, with adverse impacts on agricultural productivity, rural livelihoods, biodiversity, and on food
security in some places. Numerous connections to local and global environmental problems such as climate change and ongoing drought call for action-oriented science to inform management and decision making. We identified five soil priorities of particular importance in Chile.
Keywords: Andisols; Andosols; Land use change; Soil education; Soil information system; Soil management; Soil policy
Smith-Ramirez, C., Grez, A., Galleguillos, M., Cerda, C., Ocampo-Melgar, A., Miranda, M. D., et al. (2023). Ecosystem services of Chilean sclerophyllous forests and shrublands on the verge of collapse: A review. J. Arid Environ., 211, 104927.
Abstract: Dryland forests are the areas most threatened by climate change, urbanization and land-use change simulta-neously. Ecosystem services provided by Mediterranean dryland forests are have been in steep decline, and are extensively studied in the Mediterranean basin, however considerably less in other areas with Mediterranean climates. Knowledge of these services is necessary for the promotion of their conservation and restoration. Here, we synthesize current knowledge regarding the main ecosystem services provided by Chilean Mediterranean sclerophyllous forests and shrublands (SFSh). This knowledge allows for the valuation of SFSh in order to conserve, restore and study them. We found 158 studies, including technical reports, theses, and scientific literature regarding the social and environmental benefits derived from Chilean SFSh, though many did not use the term “ecosystem services” (ES). We found data on 19 ecosystem services with four or more studies per service. ES studies in Chile increased in number a couple years after Millennium Ecosystem Assessment published its synthesis in 2005. The most frequently reported services were provisioning services, especially medicinal plants and extracts. Despite the advances in knowledge, ecosystem services of SFSh appear to be rarely quan-tified, most frequently using oversimplified variable indicators. Services related to animal biodiversity, such as
Keywords: Dryland forests; Mediterranean forests; Cultural services; Provision services; Regulation services