In contrast, Jackson saw that nearby fields of annual crops, such as maize, sorghum, wheat, sunflowers and soybeans, required frequent and expensive care to remain productive.

• 杰克森也看到邻近农田种植的一年生作物（例如玉米、高粱、小麦、向日葵和黄豆），情形刚好相反，需要频繁且高花费的照顾才能维持生产力。