To obtain the rice from the crop, the order of separation techniques will you apply is

i) winnowing      ii) Threshing          iii) sieving         iv) Hand picking

The order of separation techniques are

ii) Threshing: separation of grains from stalks.  

i) Winnowing: Separation of husk from grains.

iv) Hand picking: Pebbles, stones are separated

iii) Sieving:  To separate pure rice grains from the pieces of rice and powder of rice.