Crop rotation and yield-time adjustment
Organic grain production frequently uses a different
rotation system than conventional production. For example,
it is common in organic systems to have a three or fouryear
rotation (with legumes or other crops) for corn, while
the conventional rotation often involves planting corn every
other year. In situations like this, it is difficult to make
yield comparisons between organic and conventional
systems without some sort of time adjustment. Although
the high variation among rotation systems worldwide
makes it impossible to provide a general time–yield adjustment,
evaluating potential differences in performance
is important. A thorough evaluation of the rotation effect
requires knowledge of the plot-to-plot yield differences
between organic and conventional production and the rate
of decline of both organic and conventional production as
a function of the rotation sequence—information that has
not yet been experimentally demonstrated. While rotations
would undoubtedly differ under a global organic production
system, we have no basis for concluding that this system
would be unable to provide enough grain to feed the world