I can tell you a little bit of the situation i Norway in the meadival period in general, as the laws regarding this did not change that much during this period. Despite the laws not changing that much, it is important to mention that prior to the 13th century there existed four different laws for different part of the country. These laws are quite similar, but they vary a little bit based on the resources in the different areas.

Firstly "Landsloven" was implemented in the middle of the 13th century and it gave the king the possibility to forcibly take seeds for crops if there was a shortage. He would need to pay a reasonable payment for these seeds, but it helped ensure that the whole country had the seeds that they needed and that no one stocked up on seeds to increase the prices while other died of starvation. Furthermore "Landsloven" also said that if there was a shortage of seeds no grain could be used to brew bear, unless ypu had permission from the king.

Secoundly "Landsloven" and some of the local laws that predated it had regulations on how often you should use a field and how much fertilizer you should use. This was to ensure that they had the ammount of fertilizer necessary to keep the soil quality high. Some of the local laws( mainly "Gulatingsloven") did not limit this because in the areas these laws affected they kept more farm animals and there where therfore a larger supply of dung for fertilizer.

Laws also regulated when to send the farm animals to mountain pastures to ensure that the ground around the farms would not get used to much, as this would destroy it and then it could not support the animals for the following years. This would be a large problem for many farmers since keeping farm animals was the most important way og getting food for many farmers, especially in the wester and northern parts of the country.

Hunting, fishing and gathering was also important both to feed the farmers and the farm animals, as food for the winter was often scarce. Therefore they often mixed bark or seaweed into the grain when making bread to make the little grain they had last for longer.

As far as i know there where no laws enforcing the storage of food, but it would be necesary to store food for the winter to survive as it would be hard to grow or gather for food during it. For more long-term storage i am not sure, but i asume they stored what they could, altough i dont think they would have much to store after a winter. The grain they planted did not yield much and the soil was generally bad. The farming methodes used was not as good as they could be and this also reduced the crop yield and increased the risk of bad harvests and famine. The animals too, was a lot worse then the one we have today so they would give less meat, milk or wool. The work animals was generally smaller and weaker too.

Sorry for my bad english, english is not my first language and i am writing on my phone at the moment. Please ask questions if anything is unclear and i will try to explain it in a better way.