Multiple cropping is growing more than one kind of crop in the same area. This can be done in a number of different ways. There is relay cropping and double cropping. Relay cropping is starting one crop among another crop that has matured. Double cropping is another form of multiple cropping where one crop is started after the growing season for the previous crop has ended. This agricultural technique normally is used to help maintain nutrient levels in the soil.
Multiple cropping is very useful for a number of reasons. Both relay and double cropping are good for replacing nutrients in the soil that one type of plant might have used heavily. There are some plants that need a large amount of nitrogen to grow, for example. These plants use up the nitrogen stores in the soil, so another kind of plant that puts nitrogen in the soil is planted in the off season. Legumes are a well-known nitrogen fixing plant.