Browsing by Author "Gil, P. M."

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    Effect of soil water-to-air ratio on biomass and mineral nutrition of avocado trees
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2012) Gil, P. M.; Bonomelli, C.; Schaffer, B.; Ferreyra, R.; Gentina, C.
    In Chile, expansion of avocado production has resulted in many orchards established in marginal soils that are poorly drained and have high soil water-to-air ratios when soil moisture is at field capacity. However, avocado trees are sensitive to poor soil aeration. A study was conducted to determine the effects of different soil water-to-air ratios (W/A) on biomass and nutrient content of avocado trees. Two-year-old avocado trees were grown for 2 seasons in containers in soils, with different W/A, collected from different avocado growing regions of Chile. There were five treatments corresponding to each of the five soils. At field capacity, the two-season average W/A was 1.7, 1.3, 0.6, 0.4 or 0.3 for treatments T1, T2, T3, T4, or T5, respectively. The same amount of fertilizer was applied to each soil. Mineral element concentrations and total mineral element contents in leaves, shoots, wood and roots were determined for each tree in each treatment at the end of the experimental period. Shoot and root fresh and dry weights, leaf area and leaf retention were also determined. Although all treatments showed non-limiting soil oxygen conditions for avocado root growth, trees in soils with lower W/A had greater shoot and root dry weights and longer autumn leaf retention. Macro-and micronutrient concentrations in any plant tissue were not related to soil W/A. However, total tissue contents of N, P, K, Ca, Mg, C, N and B in roots and whole plants were highest in treatments with lower soil W/A. The results indicate that soil W/A significantly affects growth and mineral nutrition of avocado trees and should be considered for avocado site selection and management.
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    Physiological response and susceptibility of strawberry cultivars to the charcoal rot caused by Macrophomina phaseolina under drought stress conditions
    (2019) Sanchez, S.; Grez, J.; Contreras, E.; Gil, P. M.; Gambardella, M.
    BACKGROUND: Charcoal rot of strawberry (Macrophomina phaseolina) is an emerging disease difficult to manage, a desirable alternative is the use of resistant cultivars. However, little is known regarding the reaction of cultivars to the pathogen under water stress conditions.
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    Soil electrical resistivity monitoring as a practical tool for evaluating irrigation systems efficiency at the orchard scale: a case study in a vineyard in Central Chile
    (2021) Vargas, J. Araya; Gil, P. M.; Meza, F. J.; Yanez, G.; Menanno, G.; Garcia-Gutierrez, V; Luque, A. J.; Poblete, F.; Figueroa, R.; Maringue, J.; Perez-Estay, N.; Sanhueza, J.
    In many orchards, irrigation scheduling is designed based on data from meteorological networks and considering homogeneous soil properties. Such assumptions may result in inefficient irrigation, which is difficult to constrain without expensive or invasive techniques. Here we have evaluated the ability of the electrical resistivity tomography (ERT) for detecting meter-scale irrigation uniformity and deep percolation during irrigation. The spatiotemporal variability of soil volumetric water content (VWC) in a vineyard located near Santiago (Chile) was inferred using ERT monitoring of two irrigation cycles. The electrical resistivity structure up to 4 m depth was estimated using two-dimensional inversion of ERT data. ERT results were verified by comparing resistivity models with VWC measured with soil moisture sensors, soil properties mapped in a 2 m-depth soil pit, and the spatiotemporal evolution of VWC obtained by solving numerically Richards equation. Largest temporal variations of resistivity were observed within the root depth (1 m) and are consistent with expected relative changes in VWC during irrigation. ERT images exhibit lateral changes in resistivity at these depths, likely indicating non-uniform infiltration of water controlled by observed soil texture variations. Resistivity changes were also observed below the root zone, suggesting that a fraction of the irrigation water percolates downward. These findings can be explained by an excess of irrigation water applied during the monitoring, which was planned considering regional evapotranspiration (ET) data that overestimated the actual ET measured at the vineyard. Altogether, our results suggest that ERT monitoring during irrigation is a cost-effective tool to constrain the performance of irrigation systems.