26 CFR § 1.175-7 - Allocation of expenditures in certain circumstances.
(a) General rule. If at the time the taxpayer paid or incurred expenditures for the purpose of soil or water conservation, or for the prevention of erosion of land, it was reasonable to believe that such expenditures would directly and substantially benefit land of the taxpayer which does not qualify as “land used in farming,” as defined in § 1.175-4, as well as land of the taxpayer which does so qualify, then, for purposes of section 175, only a part of the taxpayer's total expenditures is in respect of “land used in farming.”
(b) Method of allocation. The part of expenditures allocable to “land used in farming” generally equals the amount which bears the same proportion to the total amount of such expenditures as the area of land of the taxpayer used in farming which it was reasonable to believe would be directly and substantially benefited as a result of the expenditures bears to the total area of land of the taxpayer which it was reasonable to believe would be so benefited. If it is established by clear and convincing evidence that, in the light of all the facts and circumstances, another method of allocation is more reasonable than the method provided in the preceding sentence, the taxpayer may allocate the expenditures under that other method. For purposes of this section, the term land of the taxpayer means land with respect to which the taxpayer has title, leasehold, or some other substantial interest.
(c) Examples. The provisions of this section may be illustrated by the following examples: