Mitigation measures to improve physiology and productivity of olive trees under abiotic stresses

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Gas exchange performance and oxidative stress indicators in olive tree under different deficit irrigation strategies

Publication . Gonçalves, Alexandre; Silva, Ermelinda; Martins, Sandra; Brito, Cátia; Pinto, Luís; Rocha, Luís; Pavia, Ivo; Luzio, Ana; Dinis, Lia Tânia; Fernandes-Silva, Anabela; Rodrigues, M.A.; Moutinho-Pereira, José; Correia, Carlos M.

The predicted scenario of global warming anticipates severe summer conditions in the Mediterranean basin, with low water availability and excessive heat load. hlence, in arder to overcome the constrains that will affect olive groves and its socioeconomic value, new cropping practices focusing on water use efficiency must be investigated. In this work we aimed to investigate water management practices that can ensure the adequate compromise between yield and the quality of olive products. The study was conducted in Quinta do Prado, Lodões, Vila Flor (41°20'13. 3"N, 7°05'54. 2"W) and different irrigation strategies where investigated: full irrigation (Fl), equivalent to 100% of crop evapotranspiration (ETc), as control treatment, sustained déficit irrigation (SDI; 30% of ETc) and regulated déficit irrigation (RDI; 80% of ETc in phases l and III offruit growth and 10% of ETc in pit hardening stage). The impact of the treatments on leaf gás exchange and oxidative stress indicators during the 2016 summer was evaluated. The results indicate that both déficit irrigation strategies (DIS) allowed to maintain similar values of photosynthetic and transpjration rate and stomatal conductance as in Fl treatment, even in the afternoon period, although occasionally lower values were recorded during summer, namely in RDI plants. Meanwhile, despite the great disparity in the amount of water used among treatments, there were no significant differences in the degree of oxidative stress, judging by the comparative values of photosynthetic pigments, soluble proteins, total thiols and electrolyte leakage. Thus, the DIS used in this study allow an adequate physiological activity of olive trees and give new insights about the effect of these strategies in olive orchards. Since the field trial is located in a commercial farm, production costs, returns, and also fruit quality parameters are being recorded, analysis of which might give an economic insight regarding the sustainability of the implemented techniques.

2017Conference object

Open access

A smart controlled-release fertilizer improved soil fertility but not olive tree physiology and yield

Publication . Silva, Ermelinda; Arrobas, Margarida; Gonçalves, Alexandre; Martins, Sandra; Raimundo, Soraia; Pinto, Luís; Brito, Cátia; Moutinho-Pereira, José; Correia, Carlos M.; Rodrigues, M.A.

The use of a controlled-release fertilizer (CRF) was studied in a traditional rainfed olive grove in the northeast of Portugal where precipitation is very irregular, particularly in the spring. The objective of the study was to assess whether a CRF can improve the olive tree' s performance compared to a conventional nitrogen (N) fertilizer (CF), by supplying N gradually and reducing the risk of potential N loss from leaching. The fertilized treatments showed better plant N nutritional status, which resulted in enhanced net photosynthesis and higher leaf concentrations of total soluble sugars, chlorophylls and soluble proteins which, in turn, increased olive yield by 43% in comparison to the unfertilized control. Meanwhile, CRF show some advantages over the CF, although by an unexpected effect. Not in a direct way, by improving trees performance, but by enhancing soil fertility. The CRF treatments showed higher leveis of inorganic N in the soil by autumn, an aspect that at the outset could be interpreted as nega tive, since it could lead to N loss by leaching, but that proved to be a factor that may be behind the increase in the ol'ganic carbon, kjeldahl nitrogen and glomalin-related soil proteins. Thus, the availability of soil inürganlc-N in the autumn, in a climate in which excess precipitation and the risk of ieaching usually only occur in winter, led to weeds growth that seem to act as a catch crop, capturing residual inorganic N. Additionally, they contribute to protect the soil from erosion and to increase soi! organic matter, aspects that can benefit the agrosystem in the long-term.

2021Conference object

Open access

Foliar application of arginine, jasmone, and kaolin ameliorate photosynthesis of olive trees

Publication . Gonçalves, Alexandre; Silva, Ermelinda; Martins, Sandra; Brito, Cátia; Pinto, Luís; Rocha, Luís; Pavia, Ivo; Luzio, Ana; Dinis, Lia Tânia; Rodrigues, M.A.; Moutinho-Pereira, José; Correia, Carlos M.

In Northeast Portugal, olive orchards cover over 75000 ha and involve approximately 36000 producers, being olive oil the only saleable product for many families. Despite the physiological defense strategies that olive trees dispose against summer stress, the projected climate change characterized by severe summer conditions, with low rainfall, excessive heat load and high irradiance leveis might affect this crop. Cropping practices for adaptation of olive orchards to climate change must be pursued. In this work we aimed to investigate the introduction of foliar applications of compounds that have shown a central role in stress tolerance in different plant species. The study was conducted in an organic orchard at Quinta do Prado, Lodões, Vila Flor (41°20'13. 3"N, 7°05'54. 2"W) and shows the impact of the application of arginine (l mM), jasmonate (100 |-iM) and kaolin (5%; w/v) on leaf gás exchange parameters at 6 different times between July and October 2016. Ali compounds, specially kaolin, contributed to the improvement of the photosynthetic activity of olive trees during measurements made during August and September, mainly due to lower stomatal limitations, although a drop of non-stomatal limitations were also recorded at midday period, namely by the end of August. The present study gives new insights about the effect ofthis new cropping practice for olive orchards that can help to mitigate the harsh climatic conditions projected forthe Mediterranean summers.

2017Conference object

Open access

A controlled-release fertilizer improved soil fertility but not olive tree performance

Publication . Silva, Ermelinda; Arrobas, Margarida; Gonçalves, Alexandre; Martins, Sandra; Raimundo, Soraia; Pinto, Luís; Brito, Cátia; Moutinho-Pereira, José; Correia, Carlos M.; Rodrigues, M.A.

The use of a controlled-release fertilizer (CRF) was studied in a traditional rainfed olive grove in a Mediterranean climate where precipitation is very irregular, particularly in the spring. The objective of the study was to assess whether a CRF can improve the olive tree's performance compared to a conventional nitrogen (N) fertilizer (CF), by supplying N gradually and reducing the risk of potential N loss from leaching. The fertilized treatments showed better plant N nutritional status, which resulted in enhanced net photosynthesis and higher leaf concentrations of total soluble sugars, chlorophylls and soluble proteins which, in turn, increased olive yield by 43% in comparison to the unfertilized control. However, in general, no significant differences were found between fertilized treatments in the performance parameters of the trees evaluated, including olive yield. Somewhat unexpectedly, CRF consistently increased the soil organic carbon (C) (29%), kjeldahl-N (75%) and easily extractable glomalin-related soil proteins (EE-GRSP) (60%) and total GRSP (T-GRSP) (122%) compared to the CF. The result was ascribed to a stimulus on the development of herbaceous vegetation and eventually on the activity of the roots of the trees due to the higher soil inorganic-N availability in the autumn. Thus, some soil inorganic-N in the autumn seems to comprise a low risk of leaching, since weeds act as a catch crop and convert this inorganic N into an organic substrate, with potential benefits in the long-term for the agro-system.

2021Journal article

Open access

Fruit yield and quality of olives under different deficit irrigation strategies

Publication . Gonçalves, Alexandre; Martins, Sandra; Silva, Ermelinda; Brito, Cátia; Pinto, Luís; Rocha, Luís; Pavia, Ivo; Luzio, Ana; Nunes, Fernando M.; Rodrigues, M.A.; Moutinho-Pereira, José; Correia, Carlos M.

The Mediterranean Basin is a climate change hot spot where substantial warming and lower water availability is predicted. This scenario poses considerable challenges to olive groves, a crop with great ecological and socioeconomic importance. ln order to overcome these constrains, new cropping practices focusing on water use efficiency must be investigated. ln this work we aimed to investigate water management practices that can ensure the adequate compromise between yield and the quality of olive products. The study was conducted in Quinta do Prado, Lodões, Vila Flor (41 °20'13.3"N, 7°05'54.2"W) and a full irrigation (FI) control, applied daily, equivalent to 100% of crop evapotranspiration (ETc), was compared with three deficit irrigation strategies (DIS): regulated deficit irrigation (RDI; 80% of ETc in phases I and III of fruit growth and 10% of ETc in pit hardening stage, phase TI; 56 % of the ETc in all season), sustained deficit irrigation (SDI; 27.5% of ETc), and sustained deficit irrigation adopted by the farmer (SDIAF; 21.2% of ETc, applied weekly). The impact of treatments on fruit yield and quality during 2016 were evaluated. Using FI treatment as reference, no significant influence of RDI and SDI treatments were felt in crop yield, while the SDlAF treatment reduced it significantly (P

2018Conference object

Open access