dc.description.abstract
Nowadays, there is growing interest in exploring sustainable agricultural practices that
reduce dependence on chemical fertilizers and pesticides. One promising option could
be the use of certain ruderal species, often considered weeds, due to their potential
capacity to enhance nutrient availability for crops and contribute to the sustainability of
agricultural systems. Potassium (K) deficiency is a common limiting factor in agricultural
productivity worldwide, compromising plant growth, physiological performance, and
ultimately yield. This study evaluated whether two ruderal species, Diplotaxis erucoides
and Portulaca oleracea, can mitigate the negative effects of K deficiency on the growth
and physiology of tomato (Solanum lycopersicum var. 1870).
In a greenhouse experiment, isolated tomato plants, isolated ruderal plants, tomato
monocultures, and mixed cultures of tomato together with each of the ruderal species
were grown hydroponically under two levels of potassium supply (optimal or control, and
deficient). Throughout the study period, morphological parameters (height, stem
diameter, number of leaves) and physiological parameters (chlorophyll and flavonol
content, stomatal conductance, photosynthetic efficiency), substrate moisture, and
flowering over time were monitored and recorded. Statistical analysis was performed
using multifactorial ANOVAs to assess main effects and interactions, followed by post
hoc tests where appropriate.
The results showed that K deficiency significantly reduced tomato stem growth and
advanced flowering. The ruderal species displayed greater tolerance to K deficiency,
particularly P. oleracea, which enhanced the physiological performance of tomato in
mixed culture under nutrient-limited conditions. Specifically, tomatoes associated with P.
oleracea showed higher chlorophyll content and better photosynthetic parameters under
deficient conditions compared to isolated or monoculture tomatoes. In contrast, D.
erucoides did not show a clearly positive effect on tomato performance. These results
highlight the potential of P. oleracea as a companion plant to improve nutrient efficiency
and reduce the use of chemical fertilizers. Further field studies are needed to confirm
these effects and assess their applicability in sustainable agriculture
