In the English translation of his encyclical letter, Laudato Si, released today, Pope Francis laments that people end up working as temporary labors in the wake of changes in agriculture that have favored big farms.

Here is the English translation: 

In many places, following the introduction of these crops, productive land is concentrated in the hands of a few owners due to “the progressive disappearance of small producers, who, as a consequence of the loss of the exploited lands, are obliged to withdraw from direct production”.113 The most vulnerable of these become temporary labourers, and many rural workers end up moving to poverty-stricken urban areas. 

I tracked down the original Italian version as well which is less direct, in my opinion, in implicating temporary labor:  

I più fragili
tra questi diventano lavoratori precari [Italics mine] e molti salariati
agricoli finiscono per migrare in miserabili
insediamenti urbani. 

I assume that the Vatican translators are much better at this than I am, but the Italian word 'precari' does not mean 'temporary'.  Instead, it means 'precarious', obviously, or in more colloquial American, unsteady or insecure.  

So was the Pope making a crack at temporary employment specifically?   

I don't think so, but that is the nicest thing I can say about this deeply flawed, sloppy, verbose, meddlesome, anti-market, and, in many ways, unchristian document.