Why keep pigs together with poplars?
Free-range systems aim to support animal welfare and are common in organic pork production. However, they do represent an environmental risk due to the depositing of manure. Maximum stocking rates are prescribed assuming that nutrients released with manure will be spread uniformly in the field and may be absorbed by cover crops roots. In practice, there are several problems with these assumptions: pigs often decide to use one specific part of the paddock to defecate; sandy-soil fixes a small amount of nutrients; and herbaceous cover crops are more active during spring summer and less so in other seasons (Tagliapietra et al. 2007).