http://www.torah.org/learning/halacha-overview/chapter40.html
...The Jubilee year is exactly like the sabbatical year as regards cultivation [as it says “A Jubilee the fiftieth year shall be for you; you shall not sow and not harvest what grows by itself and not gather what is untended; for it is a Jubilee, it shall be holy for you, you shall eat its produce from the field”]; but it does not require release of loans. The commandments involving the Jubilee year, including the laws of Jewish slaves, houses in walled cities, and land consecrated to the Temple or “devoted” to the priests, apply only when all of Israel dwells in the land of Israel...
Did you perchance read the article I linked to? It looks at the economics of the ancient system. It did not claim a religious mandate to implement it as was today. Times are indeed different.
But it behooves Christians to study the particular law to determine the spirit thereof, which we can apply today.