Concept:
Fallow land refers to agricultural land that is left uncultivated for a period of time so that the soil can regain its fertility. In land-use classification, fallow land is divided into different categories depending on how long the land remains uncultivated.
Step 1: {\color{red}Understand the meaning of current fallow land.}
Current fallow land refers to land that has been left uncultivated for only one agricultural year. Farmers may leave the land fallow to restore soil nutrients and moisture before growing crops again.
Step 2: {\color{red}Differentiate from other fallow categories.}
Land that is left uncultivated for more than one year but less than five years is classified as fallow land other than current fallow. Therefore, options mentioning two, three, or five years are not correct.
Step 3: {\color{red}Select the correct option.}
The correct definition of current fallow land is:
\[
Land left without cultivation for one agricultural year
\]
Hence, the correct answer is Option (D).