What is the process of turning and loosening the soil called? 

Tilling is the process of loosening and mixing soil with various tools such as cultivators or rotary hoes to create a smooth seedbed for planting. 

Ploughing, on the other hand, typically entails cutting into the soil and turning it over to create furrows for planting using a plough (a large, heavy agricultural implement). Tilling and ploughing are both important steps in soil preparation because they help to control weeds, promote soil fertility, and create an ideal environment for seed germination and plant growth.

The process of gathering crops when they are mature and ready to be harvested is known as harvesting. 

Weeding is the process of removing unwanted plants from a crop field, such as weeds. 

The process of separating edible grain from plant stalk and chaff is known as threshing.