Articles
Mitigation of salinity stress in ‘Chandler’ walnuts through application to soil of Ascophyllum nodosum extracts: effects on growth, yield and its impact on physical and biological soil properties
Article number
1420_17
Pages
127 – 136
Language
English
Abstract
In Chile the majority of the walnut’s orchards are in semi-arid areas prone to saline conditions.
Therefore, mitigating salinity stress is a relevant issue for the farmers, especially for ‘Chandler’, the most sensitive and planted cultivar.
The aim of this study was to evaluate the effect of an extract of Ascophyllum nodosum (ANE; Acadian Organic®), applied through drip irrigation, on the vegetative and productive response in ‘Chandler’ walnut trees affected by salinity and its effect on the physical and biological soil properties.
Four L ha‑1 of ANE was applied monthly, during two seasons (2021-2022, 2022-2023), from the beginning of shoot growth until one month before harvest (24 L ha‑1 per season), contrasting with a control without amendment.
The water irrigation quality was always close to severe conditions for walnut (EC 2.0 dS m‑1 and chlorides between 250 and 300 mg L‑1). In 2021-2022, ANE applications mitigate salt damage in walnut trees, reaching a greater thickness of shoots, a higher SPAD index and better vegetative expression, represented by the NDVI spectral index.
Consequently, a higher proportion of large sizes (first season: >32 mm; 54% ANE vs. 45% control; second season: >32 mm; 26% ANE vs. 6% control) and better kernel filling, an effect that was quickly evident in the first season of applications.
The stress mitigation promoted a greater accumulation of reserves in shoots, with positive accumulated effect after 1 season of applications due to an early vegetative development in the second season and significantly higher fruit size and yield efficiency.
On the other hand, the ANE applications generated significant improvements in the physical and biological soil properties, increasing the soil microbial activity and stimulating an organic matter accumulation, which allowed to reduce compaction, improve soil structure and increase soil macroporosity in depth.
The latter is relevant for irrigation and salt management, since a higher stability of the soil porous system under irrigation cycles would allow an adequate water distribution in the soil profile, improving the displacement of salts and, consequently, reducing the saline stress.
Therefore, mitigating salinity stress is a relevant issue for the farmers, especially for ‘Chandler’, the most sensitive and planted cultivar.
The aim of this study was to evaluate the effect of an extract of Ascophyllum nodosum (ANE; Acadian Organic®), applied through drip irrigation, on the vegetative and productive response in ‘Chandler’ walnut trees affected by salinity and its effect on the physical and biological soil properties.
Four L ha‑1 of ANE was applied monthly, during two seasons (2021-2022, 2022-2023), from the beginning of shoot growth until one month before harvest (24 L ha‑1 per season), contrasting with a control without amendment.
The water irrigation quality was always close to severe conditions for walnut (EC 2.0 dS m‑1 and chlorides between 250 and 300 mg L‑1). In 2021-2022, ANE applications mitigate salt damage in walnut trees, reaching a greater thickness of shoots, a higher SPAD index and better vegetative expression, represented by the NDVI spectral index.
Consequently, a higher proportion of large sizes (first season: >32 mm; 54% ANE vs. 45% control; second season: >32 mm; 26% ANE vs. 6% control) and better kernel filling, an effect that was quickly evident in the first season of applications.
The stress mitigation promoted a greater accumulation of reserves in shoots, with positive accumulated effect after 1 season of applications due to an early vegetative development in the second season and significantly higher fruit size and yield efficiency.
On the other hand, the ANE applications generated significant improvements in the physical and biological soil properties, increasing the soil microbial activity and stimulating an organic matter accumulation, which allowed to reduce compaction, improve soil structure and increase soil macroporosity in depth.
The latter is relevant for irrigation and salt management, since a higher stability of the soil porous system under irrigation cycles would allow an adequate water distribution in the soil profile, improving the displacement of salts and, consequently, reducing the saline stress.
Publication
Authors
V. Beyá-Marshall, F. Quintanilla, O. Seguel, C. Kremer, E. Vargas, T. Fichet
Keywords
biostimulants, salt tolerance, saline soil, sustainable management, soil organic matter
Groups involved
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