Comparison

Crop rotations—sequentially planting different crop species on the same plot of land—are an important strategy for building soil health on farms. In particular, including leguminous plants that fix atmospheric nitrogen in a rotation has the potential to increase the amount of nitrogen, an important plant nutrient, in the soil. This comparison includes studies that evaluate the effect of crop rotations on soil nitrogen content relative to continuous crop monocultures, cropping systems where the same crop species is repeatedly planted on the same plot of land over time. Papers included in the comparison were identified through a Web of Science search that included the following search terms: "legum* rotation*" AND ("soil nutrient*" OR phosphorus* OR nitrogen* OR potassium*) AND (effective* OR performance* OR assessment* OR evaluation* OR estimate* OR comparison* OR contrast*). Selected papers include those that were either open access or accessible through the University of Leibniz, Hannover Technical Information Library, and that provided information on soil nitrogen levels in the text or in tables; data presented in figures or plots that required extraction were not included in this comparison. The search yielded 58 papers; data from four papers met the eligibility criteria and were included in the comparison.