EL PASO, Texas (July 27, 2026) — A simple, low-dose leaf spray could give farmers a practical new tool to keep growing tomatoes on land that salt has rendered increasingly unproductive, according to a study led by a researcher at The University of Texas at El Paso.
"Salinity is one of the most pressing threats to global food security, and growers need solutions they can actually put to use in the field," said Hamidreza Sharifan, Ph.D., an assistant professor of chemistry at UTEP who served as the study’s corresponding author.
The findings could carry real weight for global agriculture.
High levels of salt in soil can prevent plant roots from absorbing water, which can lead to slowed photosynthesis. Excess salt can also become toxic for plants, and lead to nutrient deficiencies, which in turn leads to reduced crop productivity.
According to the research team, soil salinity affects more than 3.2 million square miles of land globally – an area roughly the size of Australia or Brazil – and threatens 20% to 30% of the world's irrigated cropland, especially in arid and semi-arid regions.
Tomatoes rank among the most widely grown vegetables on Earth, with global production reaching roughly 192 million tons in 2023. So, even modest gains in salt tolerance could protect a significant share of the food supply, the researchers explained.
The team’s treatment pairs manganese oxide nanoparticles with chitosan, a natural biopolymer derived from crustacean shells, in a solution that is applied directly to plant leaves. In greenhouse trials, the two-part spray substantially reversed the damage that salty soil inflicts on tomato plants, pointing to an affordable and sustainable option for the farmland worldwide that is degraded by salt.
"What makes this approach exciting is that it is low-cost, sustainable and effective at very small doses.” Sharifan said. “We are giving plants the tools to protect themselves instead of fighting the salt head-on."
Published in the International Journal of Phytoremediation, the study tested the spray on tomato plants exposed to moderate and severe salt stress. Under the harshest conditions, the combined treatment doubled shoot weight and increased root weight by more than 55% compared with untreated, stressed plants. It also restored photosynthetic pigments, raising carotenoid levels by roughly 91% and sharply lowered chemical markers of cellular damage. Antioxidant enzyme activity climbed by as much as 300%, helping the plants defend themselves against stress rather than succumb to it.
The team cautioned that the results come from controlled greenhouse conditions and that field trials will be needed to confirm the spray's performance at scale. Future studies will also examine long-term effects on soil health and environmental safety. Even so, the authors described the strategy as a promising, environmentally friendly path toward more resilient crops.
About The University of Texas at El Paso
The University of Texas at El Paso is America's leading Hispanic-serving university. Located at the westernmost tip of Texas, where three states and two countries converge along the Rio Grande, 84% of our 26,000 students are Hispanic, and more than half are the first in their families to go to college. With respect to research, UTEP is in the top 5% of universities in America and offers 169 bachelor's, master's and doctoral degree programs at the only open-access, top-tier research university in America.
International Journal of Phytoremediation
Synergistic alleviation of salinity stress in tomato: unraveling the physiological, biochemical, and antioxidant mechanisms modulated by manganese nanoparticles and chitosan
18-May-2026