If you back the water tank trailer into the river, you can load it to fill it with water.
There are two silos near the railroad tracks that you can use at the start of the game when you don’t have enough money to buy your own silos. Small fields can be combined into a larger field, while large fields can be divided into smaller fields. Rather than buying a large trailer, consider buying multiple smaller trailers so that you can use them separately for small tasks or combine them for larger tasks. Trailers can be linked together to transport larger loads.
