The Royal Institution of Chartered Surveyors (Rics) found the average price of land fell by £750 to £3,625 per acre in the second half of 2015.
A survey suggested there was a fall in demand during the period.
Rics said the global fall in crop prices meant land values were expected to continue to decline over 2016.
Its survey was conducted along with the Royal Agricultural University.
A net balance of 67% of chartered surveyors reported a fall in demand for rural land across the country in the second half of last year. At the same time land availability increased, with 83% of respondents reporting a pick-up.
As a result, a net two-thirds of rural surveyors said they expected to see prices drop this year.
Rics in Scotland director Sarah Speirs said: "Rural land prices have increased in Scotland over recent years. However, the latter half of 2015 saw prices and demand fall and the global fall in crop prices is likely to cause values to continue to decline over the next 12 months.
"Additionally, with commercial and residential property prices in towns and cities continuing to rise, this is likely to make rural land increasingly attractive to those outside traditional farming communities.
"We are already seeing growth in countryside land in Scotland being purchased by non-farmers - lifestyle buyers or hobby farmers."
Scottish rural land prices are likely to continue falling over the next 12 months after tailing off towards the end of 2015, according to a report.