Strategies for Improved Yield and Water Use Efficiency of Lettuce (Lactuca sativa L.) through Simplified Soilless Cultivation under Semi-Arid Climate

Nicola Michelon,Giacomo Dall’Olio,Lucrecia Pacheco Batista,Giuseppina Pennisi,Nazim S Gruda,Francesco Orsini,Giorgio Gianquinto,Adeodato Ari Cavalcante Salviano,Nang Ohn Myint

doi:10.3390/agronomy10091379

Abstract

Simplified soilless cultivation (SSC) systems have globally spread as growing solutions for low fertility soil regions, low availability of water irrigation, small areas and polluted environments. In the present study, four independent experiments were conducted for assessing the applicability of SSC in the northeast of Brazil (NE-Brazil) and the central dry zone of Myanmar (CDZ-Myanmar). In the first two experiments, the potentiality for lettuce crop production and water use efficiency (WUE) in an SSC system compared to traditional on-soil cultivation was addressed. Then, the definition of how main crop features (cultivar, nutrient solution concentration, system orientation and crop position) within the SSC system affect productivity was evidenced. The adoption of SSC improved yield (+35% and +72%, in NE-Brazil and CDZ-Myanmar) and WUE (7.7 and 2.7 times higher, in NE-Brazil and CDZ-Myanmar) as compared to traditional on-soil cultivation. In NE-Brazil, an eastern orientation of the system enabled achievement of higher yield for some selected lettuce cultivars. Furthermore, in both the considered contexts, a lower concentration of the nutrient solution (1.2 vs. 1.8 dS m−1) and an upper plant position within the SSC system enabled achievement of higher yield and WUE. The experiments validate the applicability of SSC technologies for lettuce cultivation in tropical areas.

Highlights

The detrimental effects of climate change are resulting in dramatic environmental, economic, and social consequences across the world [1]
The increased yield was mainly due to leaf number, as Thai plant grown adopting NS1.2 showed the highest number of leaves (12.9 leaves plant−1 ) while no differences were observed between the other treatments
For plants grown in the lower part of the system (LP), stomatal conductance was only affected by CV, and was higher in cv Thai for both considered electrical conductivity (EC) (Table 6)

Summary

Introduction

The detrimental effects of climate change are resulting in dramatic environmental, economic, and social consequences across the world [1]. Agronomy 2020, 10, 1379 countries, located in tropical areas, are vulnerable to climate change due to their dependence on rain-fed agriculture, widespread poverty, and limited access to innovative technologies and improved agricultural practices [7]. An evident interdependence between climate change, economic vulnerability and migrations exists [8]. Climate change is resulting in a growing rate of migration toward urban and periurban areas of large cities. Adaptation mechanisms are not yet in place, or are not strong enough, to mitigate the economic vulnerability of the most impoverished strata of the population [8]. In the tropical areas of Latin America and South-East Asia, health concerns are related to different forms of malnutrition frequently associated with a lack of micronutrients and vitamins in the population diet and low dietary diversification [9]

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Discussion

Conclusion