11.1: Introduction

... with methods of farming in which grasses form an important part of the rotation, especially those that leave a large residue of roots and culms, the decline of the productive power is much slower than when crops like wheat, cotton, or potatoes, which leave little residue on the soil, are grown continuously.

—Henry Snyder, 1896

There are multiple ways to diversify cropping systems, and there are good reasons to do so. One important ecological principle is that diversity contributes to stability and productivity (see discussion in Chapter 8). Diversity over time in a field, year to year, is achieved by using cover crops and by rotating a number of crops. You can also diversify spatially, or across your farm’s landscape, by planting different crops in different fields or in strips within fields. A well-planned crop rotation—for example, one that might use the same sequence of crops but staggered differently from one field to the next in a given year or season—provides diversification both over time and across the farm landscape. Crop diversification can also occur with less frequent rotations by using perennials. For example, dairy farmers may grow alfalfa for three to four years before it is rotated to corn. Agroforestry, the growing of tree species together with annual crops or other perennials, affords another way of adding habitat diversity to a farm. Integrating livestock and cropping brings yet another dimension of diversity by introducing animals onto the farm. Of course, all three—crop rotations, agroforestry and integrating livestock—can be practiced together. In this chapter we’ll discuss crop rotations and agroforestry. Integrating crops and livestock is discussed separately in the following chapter (Chapter 12).