The New Jersey Constitution of 1947 (Annotated) Art. VIII, § I, ¶ 1

1. (a) Property shall be assessed for taxation under general laws and by uniform rules.  All real property assessed and taxed locally or by the State for allotment and payment to taxing districts shall be assessed according to the same standard of value, except as otherwise permitted herein, and such real property shall be taxed at the general tax rate of the taxing district in which the property is situated, for the use of such taxing district.

(b) The Legislature shall enact laws to provide that the value of land, not less than 5 acres in area, which is determined by the assessing officer of the taxing jurisdiction to be actively devoted to agricultural or horticultural use and to have been so devoted for at least the 2 successive years immediately preceding the tax year in issue, shall, for local tax purposes, on application of the owner, be that value which such land has for agricultural or horticultural use.

Any such laws shall provide that when land which has been valued in this manner for local tax purposes is applied to a use other than for agriculture or horticulture it shall be subject to additional taxes in an amount equal to the difference, if any, between the taxes paid or payable on the basis of the valuation and the assessment authorized hereunder and the taxes that would have been paid or payable had the land been valued and assessed as otherwise provided in this Constitution, in the current year and in such of the tax years immediately preceding, not in excess of 2 such years in which the land was valued as herein authorized.

Such laws shall also provide for the equalization of assessments of land valued in accordance with the provisions hereof and for the assessment and collection of any additional taxes levied thereupon and shall include such other provisions as shall be necessary to carry out the provisions of this amendment.