Organic Cultivation and Deficit Irrigation Practices to Improve Chemical and Biological Activity of Mentha spicata Plants

Antonios Chrysargyris,Eleni Koutsoumpeli,Panayiota Xylia,Maria Konstantopoulou,Anastasia Fytrou,Nikolaos Tzortzakis

doi:10.3390/agronomy11030599

Antonios Chrysargyris, Eleni Koutsoumpeli + Show 4 more

Open Access

https://doi.org/10.3390/agronomy11030599

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Abstract

Intensive crop production and irrational use of fertilizers and agrochemicals have questionable effects on the quality of products and the sustainable use of water for agricultural purposes. Organic cultivation and/or deficit irrigation are, among others, well appreciated practices for a sustainable crop production system. In the present study, spearmint plants (Mentha spicata L.) were grown in different cultivation schemes (conventional versus organic cultivation, full versus deficit irrigation), and effects on the plant physiological and biochemical attributes were examined in two harvesting periods. Deficit irrigation decreased plant growth, but increased total phenolics, flavonoids, and antioxidant capacity of the plants at the second harvest. Spearmint nutrient accumulation was affected by the examined cultivation practices; nitrogen was decreased in organic cultivation, potassium and sodium were elevated at full-irrigated plants, while magnesium, phosphorus, and copper levels were higher at the deficit-irrigated plants. However, conventional/full-irrigated plants had increased height and fresh biomass at the first harvest. Essential oil content decreased at the second harvest in organic and/or deficit treated plants. Additionally, deficit irrigation affected plant growth and delayed the formation of carvone from limonene. The essential oils were further evaluated with regard to their bioactivity on a major vineyard pest Lobesia botrana. Volatile compounds from all essential oils elicited strong electroantennographic responses on female insects antennae, highlighting the role of carvone, which is the major constituent (~70%) in all the tested essential oils. M. spicata essential oils also exhibited larvicidal activity on L. botrana, suggesting the potential of their incorporation in integrated pest management systems.

Highlights

To provide enough food for an expanding world population, a massive increase in crop production is required in order to meet the food demands of future generations, while preserving the ecological and energy-related resources of our planet [1]
The analysis of data was accomplished with the use of IBM SPSS vs. 22, where the effects of cultivation practice, irrigation, and harvesting period, as well as their interactions on the plant growth, physiological, biochemical, and nutrient content, and essential oil yield and composition of samples were assessed with three-way analysis of variance (ANOVA)
R-(–)-carvone, which is the predominant component in all samples (~70%), may be the main or sole contributor to the observed electrophysiological responses and larvicidal effects on L. botrana, providing an explanation for the uniformity of results. These findings suggest that, despite the differences in essential oil yield and composition between different cultivation and irrigation regimes, organically grown M. spicata plants combined with a deficit irrigation plan can be as good an option as conventional ones, as part of a strategy to protect vineyards in a more sustainable and environmental-friendly manner

Summary

Introduction

To provide enough food for an expanding world population, a massive increase in crop production is required in order to meet the food demands of future generations, while preserving the ecological and energy-related resources of our planet [1]. The effect of cultivation practices on crops is well reported in the literature, as the selection of the appropriate ones improves crop quality and productivity [4,5,6]. The application of an unsuitable practice may reduce the ability of crops to produce high yields, increase the concentration of minerals in the soil up to toxic levels, contaminate waters, and degrade soil quality [7,8]. The selection and the combination of different cultivation practices that demand low inputs (such as the organic cultivation) or a less water demanding crop may result in a more eco-friendly and sustainable farming system [9], but when applied to aromatic and medicinal plants, may reveal improved or new properties of the plant extracts [5]. Fresh water scarcity in arid and semi-arid regions leads the way to adopting new water-conserving strategies without limiting the dietary features and the biological properties of produced plants [9]

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