Is There Scientific Evidence for the Impact of Shmita on Soil?
A scientific-Torah review of the environmental effects of land rest
We all know the verse:
“And the land shall observe a Sabbath to the Lord” (Leviticus 25:2).
But is the rest of the land in the seventh year - the Shmita year - only a spiritual commandment, or does it also have real scientific and ecological effects?
In this article, we will review scientific data on the impact of the Shmita year on the soil and examine: Does the soil truly heal from constant cultivation? What benefits (and perhaps drawbacks) are found in ceasing to work the land, and what is the connection between the Torah and modern sustainable agriculture?
Shmita as an Ecological Timeout
In Israel, thanks to Shmita-observant farmers, a rare opportunity arises once every seven years: a comparison between fields that rested (no cultivation, no fertilization, and no spraying) and fields that were worked as usual.
Dr. David Bonfil, an agronomist at the Gilat Research Center of the Volcani Institute for over 25 years, conducted a dedicated experiment to examine the impact of Shmita on field crops in the Negev. His findings:
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In plots that rested, rainwater use efficiency increased - not because more water was given, but because the rain was absorbed and stored in the soil and utilized better in the year following the rest.
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The result was consistent across all crops tested: watermelon, sunflower, cotton, and sorghum. They all responded the same way, because they received more available water from the soil.
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The rest year was found to have a contribution to plant protection: the rest disrupted the life cycle of weeds and pests, leading to a cleaner field in the following year.
How Does This Happen? Three Main Mechanisms
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Water storage: In arid regions, every drop counts. In a year with no crops, rain is not absorbed by plants but rather seeps in and is preserved deep in the soil. This way, the roots of the next crop encounter a water reservoir that accumulated over an entire year.
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Biological soil rehabilitation: Rest allows beneficial fungi, decomposing bacteria, and earthworms to thrive without disturbance. Data from Rothamsted experiments in England (since 1843, the longest-running agricultural experiment in the world) shows that in the first years of rest, plant residues decompose and release mineral nitrogen available for the next crop. It is important to note: prolonged fallow without plant cover actually depletes the soil’s organic carbon and nitrogen reserves, which is why short rest (like a single Shmita year) is more effective than prolonged fallowing.
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Natural mineral release: Without harvesting and without plowing, organic residues decompose and nourish the soil. When microorganisms are active without disturbance, they break down organic matter and release nitrogen and additional minerals into the soil naturally.
What About the Yield After Shmita?
Research in dryland farming, including Dr. Bonfil’s experiments at Gilat, shows improvement in yield after a rest year - thanks to soil saturated with moisture, balanced, and low in weeds. Shmita-observant farmers consistently report particularly strong fields after the seventh year.
It is important to note: the degree of improvement varies greatly and depends on crop type, rainfall amount, and soil type. In drought conditions, the difference between a field that rested and one that was continuously worked can be dramatic. Under normal conditions, the improvement is moderate but consistent.
Shmita and the Climate Crisis
Prof. Rattan Lal, Director of the Carbon Management and Sequestration Center at Ohio State University, found that cultivated soils worldwide have lost between 50% and 70% of the carbon they once contained - carbon that entered the atmosphere as carbon dioxide. Healthy soil functions as a “natural sink” for carbon: through photosynthesis, plants absorb carbon and transfer it to organisms in the soil.
Land rest - as in a Shmita year - is one of the simplest ways to allow soil to rehabilitate its carbon reserves. Research by Northeastern University and The Organic Center found that soils not intensively cultivated show 26% more potential for long-term carbon storage compared to conventional soils.
Comparison to Sustainable Agriculture Worldwide
The idea of land rest also exists in other ancient agricultural cultures and in modern agriculture:
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Fallow - deliberate field idling, common in agriculture since ancient times.
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Cover crops - vegetation grown not for harvest, but for soil rehabilitation.
What distinguishes the Torah is the establishment of a fixed, obligatory cycle of once every seven years - combining soil rehabilitation with a complete social-spiritual system that also includes debt release and the renunciation of produce.
What Are the Risks?
A Shmita year requires proper management. A completely abandoned field may suffer from rain erosion, develop resistant weeds, or become a habitat for rodents.
Therefore, it is important to combine observance of the law with agricultural understanding - such as leaving natural ground cover or neutralizing harmful weeds through permitted methods.
What Does All This Teach Us?
Shmita, beyond being a commandment, is also practical environmental wisdom. It gives the land what we forget to give it in our routine: space to breathe, time to renew, an opportunity to recover.
Maimonides already wrote (Guide for the Perplexed III:39) that the purpose of Shmita is “that the land will increase its produce and be strengthened by lying fallow” - that the soil grows stronger precisely when it rests. Modern science, as we have seen, confirms this logic.
The Future: Combining Torah and Science
There is still room for research: How does Shmita affect the nutritional value of fruits? Can kosher cover crops be developed for the seventh year? And is one Shmita every seven years sufficient, or is additional conservation needed?
Science is beginning to provide quantitative support for what the Torah established thousands of years ago: that the land needs rest - not just humans.
Bottom line: Shmita is both a divine commandment and an environmental, economic, and human opportunity. Scientific data shows that land rest improves its fertility, protects against pests, and contributes to the fight against climate change. This is the wisdom of a Sabbath for the land.