Poden determinades

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

15