What does fallow period in agriculture mean

From Longman Dictionary of Contemporary Englishfallowfal‧low /ˈfæləʊ $ -loʊ/ adjective1TAfallow land is dug or ploughed but is not used for growingcropsThey let the land lie fallow for a year.2 →fallow periodExamples from the Corpusfallow• In many districtscattle were thought essential for ricecultivation, and when there was a shortagefieldslayfallow.• It requires field use to be rotated annually, or fields to be left fallow every one or two years.• In April, new life springs forth from fallow land.• Surely we each agree that fallow or underused land is of no help to the economicsituation.• They've started producingfilms again after a two-year fallowperiod.• Properly looked after they can produce several crops a year and remainfertile for centuries without needing a fallow period.• Nutrientrenewal also occurs more rapidly under a managedfallow system than it does under unmanaged fallow for a number of reasons.lie fallow• On the year of jubilee all slaves are freed, all debts are cancelled and the land lies fallow.• Part of the arablesoil still lies fallow.• Pestsoverwintering in stubble or soil are foiled by clearing stubble after harvest or letting the land lie fallow.• Some of these would therefore lie fallow.• Three of these are allocated to different crops and the fourthlies fallow.• We went here and there, but Kungsleden lay fallow.• After lying fallow for nearly 50 years, conventionsderiving from the UniversalDeclaration were shown to have teeth.• He can not resign himself to seeing the least plot of groundlay fallow or denied the opportunity to produce a crop.