A study by two sociologists warns that Jewish fund raising in the U.S. may face a "chronic drought" in future years unless greater commitment to "Jewishness" can be restored among American Jews.

The report by Professors Paul Ritterband of City College of New York and Steven Martin Cohen of Queens College established a clear link between giving and commitment to Jewish tradition or communal life.

In general, the higher the individual's Jewish observances in such things as performing mitzvot (good deeds), reading Jewish books, going to Israel, or belonging to Jewish organizations, the more likely that person will give to Jewish causes.

The study revealed that "Jewishness" appears to be declining. "At all ages," the researchers reported, "Jews in 1975 were generally less Jewish on average than were comparable Jews a decade earlier. Jewishness is declining."

Degrees of "Jewishness" were measured on the basis of the individual's behavior on a range of Jewish activities such as keeping a kosher home, attending synagogue, and reading Jewish newspapers.

The researchers found that regardless of age, persons who rated high in Jewish behavior donated significantly more than persons low in Jewishness.

"There are somewhere around 1.8 million Jewish households in the United States," the researchers said in their study, called "Will the Well Run Dry?The Future of Jewish Giving in America."

"If all were like the 30-44 low Jewishness households, the total collected would be $57 million; if all were like the age 45-60 high Jewishness households, the total would be $483 million."

The report on Jewish giving is the first of five policy studies that will be published in 1979 by the National Jewish Conference Center here, directed by Irving Greenberg.

Ritterband and Cohen said "the capital stock of Jewish philanthropy is Jewishness. Without Jewish commitments, Jewish fund raising would be in very serious trouble. Our analysis suggests that the trouble is just around the corner: 33 percent of the 45-60-year age group has high Jewishness as compared with only 28 percent of the 30-44-year group -- and only 8 percent of those in their 20s."