Why were threshing machines introduced by the landlords ?

(i) During the Napoleonic wars, prices of foodgrains were high and farmers
expanded their production.
(ii) Fearing a shortage of labour, they began buying the new threshing
machines that had come into the market.
(iii) They complained about the drinking habits of the labourers, thereby
making it difficult for them to work.
(iv) They thought that machines would help them reduce their dependence
on labourers.