106971
The fact that a fallow period must be included in the crop rotation means that fields cannot always be protected by a cover crop , which might otherwise offer protection against erosion .
 cover crop
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 cover crop