Hi there Raul;
The sugar production rate and the flour production rate are poorly balanced to the production capacity of the land.
A 1000 lot farm produces 1000 wheat units every 40 hours.
Just balancing the facility production to the land production means
that the windmill should process the 1000 wheat units in 40 hours, i.e. processing 25 wheat units per hour.
Likewise for Sugarcane :
A 1000 lot farm produces 1000 sugarcane units every 12 hours.
Just balancing the facility production to the land production means
that the sugar mill should process the 1000 sugarcane units in 12 hours, i.e. processing approximately 84 sugarcane units per hour.
Given than beets and grapes grow in 4 hours, it is reasonable to desire the sugarcane and wheat processing to complete in 4 hours for a batch of 1000 units, produced by a 1000 lot farm.
This requirement leads to the following processing capacities:
1000 units of crop be processed in 4 hours i.e.
a processing rate of 250 units/hour.
The current processing rate of 10 sugarcane units every 2 hours is simply preposterous, as it is
2% (yes two percent!!) of a reasonable processing rate; (5 units per hour versus reasonable rate of 250 units/hour).
So is the processing rate of wheat; at 10 wheat units every 30 minutes it is worse than snails pace at 8% (eight percent !) of the reasonable processing rate ( 20 units/hour versus reasonable rate of 250 units/hour).
I know that you guys want us to enjoy the game. 
Please adjust the mills' processing rates to 250 crop units/hour. 