Chapter 6

Cover Crops for Organic Farms

Catch Crops

A catch crop is a cover crop grown to take up available nitrogen in the soil and thereby reduce leaching losses of nitrogen already in a cropping system (See Figure 6.4). Where nitrate leaching is a serious problem, catch crops can beneficially fill any “fallow” periods in a rotation. Catch crops are planted after cash crops are harvested or following legume plowdowns or manure spreading to hold onto easily leached nitrogen and other nutrients. One of the most vulnerable times is between fall and spring, during times of heavy rain and/or snow melt. Over the winter, bare soil is prone to losses of nutrients both to the air by volatilization and to the water by leaching and runoff.

Effectiveness of Catch Crops

Catch crops can be legumes or grasses. In general, legume cover crops do not scavenge nitrogen as well as grasses. If you need a cover crop to take up excess nutrients after manure or fertilizer applications, a grass, a brassica or a mixture is usually a better choice.

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