b. In four-field crop rotation system, wheat, barley, turnips, and clover would be planted in that order in each field in successive years. The turnips helped keep the weeds down and were an excellent forage crop—ruminant animals could eat their tops and roots through a large part of the summer and winters. There was no need to let the soil lie fallow as clover would add nitrates (nitrogen-containing salts) back to the soil. The clover made excellent pasture and hay fields as well as green manure when it was plowed under after one or two years. The addition of clover and turnips allowed more animals to be kept through the winter, which in turn produced more milk, cheese, meat, and manure, which maintained soil fertility.

This is a system of crop rotation, invented by Charles 'Turnip' Townshend, which involves the planting of Clover and turnips after wheat, oats, and or barley, so as to regain the lost nutrient, back into the soil

Explanation:

This is a system of crop rotation, invented by Charles 'Turnip' Townshend, which involves the planting of Clover and turnips after wheat, oats, and or barley, so as to regain the lost nutrient, back into the soil. Often carried out on a four year cycle.

This in turn leads to the creation of animal fodder, the enrichment of the soil and the production of food for people.

Hence, given the animals to be grazing on the clover and turnip fields, eating the crop, their droppings helped to improve the fertilizers content in the soil.

The four field system is considered a success because, the result shows that there is improvements in the quantity of food produced.