Which of the following is the reason for low yield per acre and high yield per person in Extensive Commercial Grain Cultivation ?

Large land area and mechanised farming

In Extensive Commercial Grain Cultivation yield is low per acre but high yield per person because the size of farms is very large and there is low pressure per unit area of land which makes its yield low per acre but all the operation from ploughing to harvesting are mechanised that makes it per person yield high.