AT NATURE'S PACE: Farming and the America Dream by Gene Logsdon (Pantheon: $12; 208 pp.). Gene Logsdon presents the case for sane, sustainable agriculture in these warm essays. As a model, he offers the Amish communities of his native Ohio, whose small farms boast higher profit margins than agribusiness empires, despite their avoidance of technology. Logsdon wants to replace chemicals, spiraling debt and soil-exhausting monoculture with healthful crops and a sense of connection with the land: " . . . sustainable farms are to today's headlong rush toward the earth's destruction what the monasteries were to the Dark Ages: places to preserve human skills and arts until some semblance of common sense and common purpose return to the public mind."