Lost? How about some details. Were they combined into larger farms? Sold for urban development or energy production? Abandoned to wilderness? The “solution”, if there needs to be one, is different for each case. This looks like a case of agriculture bureaucrats setting themselves on fire to get more cash.
Has actual agricultural production decreased? Are farms simply more efficient so less land is required to satisfy market demand without collapsing the price via overproduction? Lot of questions to answer.