759. Fertilizing a Field on Chol HaMoed
104:6 On chol hamoed, a Jew may not perform even permitted forms of labor for a non-Jew.
104:7 One may not spread manure on his field on chol hamoed. One may not even let sheep in there so that they may lay the manure naturally. This is likewise prohibited to be done through a non-Jew. (For mitigating factors, see OC 537:14.)