Spreading support system and server

A spreading support system comprising:

• a harvest vehicle configured to harvest crops from a surface of soil in an agricultural field, the harvest vehicle being configured to detect a yield of the harvested crop;
• a land vehicle, including:
• a position detector to detect a position of the land vehicle;
• a height detector to detect a height of the land vehicle above the surface of soil in an agricultural field, the height detector including an inertial measurement unit which includes an acceleration sensor to detect acceleration, and a gyroscope sensor to detect angular velocity, the inertial measurement unit being capable of detecting roll angle, pitch angle, and yaw angle of the land vehicle;
• and
• a height difference data generator to generate data about differences in elevation of the land vehicle based on the position given by the position detector and the height determined by the height detector;
• a storage to store correction information indicating a correction value which varies according to variation of a height difference that is a difference in height of the surface of soil in an agricultural field from a reference height based at least on the height difference data provided by the land vehicle;
• and
• a controller configured or programmed to:
• acquire the height difference at a target position in an agricultural field based on the height difference data from the land vehicle;
• acquire a planned spread amount which is an amount of an object to be spread on a surface of soil at the target position in the agricultural field, based on at least the yield of crop information provided by the harvest vehicle;
• determine the correction value corresponding to the acquired height difference at the target position based on the correction information stored in the storage;
• correct, based on the acquired height difference and the determined correction value, the acquired planned spread amount to obtain a corrected spread amount for the target position;
• and
• output, for the target position, the corrected spread amount;
• wherein the correction information stored in the storage indicates that:
• the correction value corresponding to the height difference which indicates that a surface of soil at a position where the height difference is acquired is at the reference height, higher than the reference height and in a higher height range from the reference height, or lower than the reference height and in a lower height range from the reference height is a value which, if used to correct the planned spread amount, does not increase or decrease the planned spread amount to the corrected spread amount;
• the correction value corresponding to the height difference which indicates that a surface of soil at a position where the height difference is acquired is higher than the reference height and above the higher height range from the reference height is a value which, if used to correct the planned spread amount, increases the planned spread amount to the corrected spread amount;
• and
• the correction value corresponding to the height difference which indicates that a surface of soil at a position where the height difference is acquired is lower than the reference height and below the lower height range from the reference height is a value which, if used to correct the planned spread amount, decreases the planned spread amount to the corrected spread amount.