WASHINGTON, D.C. NFU has urged a federal judge to reject a proposed agreement that would allow grain giant Cargill, Inc. to purchase a com petitor Continental Grain, Co. NFU said the deal would adversely impact net farm income. The judge is reviewing an agreement between the Justice Department and Cargill that would allow the merger if a number of divestitures are made. The judge has to deter mine whether the deal is in the public interest. In comments filed recently, NFU said even with proposed divestitures the deal will signifi cantly erode competition for farmers selling their grain, mak ing it nearly impossible to earn a fair price. Cargill is the second largest grain trader in North £»=