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THE THIRD PRINCIPLE OF SOIL HEALTH

Plant Diversity tics in terms of the risk they pose, which may make some

A diverse crop rotation system consists of growing different more suitable for use in a particular location. Management
decisions must be made by individual producers to select
kinds of crops in planned sequences to take advantage of the rotation or combination of rotations that is most ap-
the power of diversity and reduce overall risk. One of the propriate for them.
most important roles of a crop rotation is to mimic the nat-
ural water and nutrient cycle while maximizing the amount By Dwayne Beck, Ph. D • Pierre, SD
of sunlight captured. Historically, rotations have been much Dwayne Beck has had more impact and influence on
Plains Agriculture in this generation than anyone else
more diverse than they are now and most included phases we know. As director of the Dakota Lakes Research
of perennial crops with livestock integration. This loss of Farm in Pierre, SD, Dr. Beck has developed his vision of
diversity was due to a myriad of economic factors including regenerative agriculture in the field and not in a labora-
tory or a classroom. His practical approach to systems
farm program characteristics; mechanization, development based agriculture is legendary and his candid style of education is refreshing
of nitrogen fertilizer sources and pesticides, and specializa- to anyone who has heard him speak.
tion in livestock production. Interest in diversifying crop
production systems has increased recently. Commodity Beck’s “Rotation Rules”
prices that are low relative to the costs of fertilizer, machin-
ery, labor, and pesticide inputs have led producers to exam- C Reduced and no-till systems favor the
inclusion of alternative crops. Tilled
ine means of reducing these costs. systems may not.
In addition, natural selection pressure resulting from longer C A two-season interval between growing a
given crop or crop type is preferred. Some
histories of tight rotations and monocultures have led to broadleaf crops require more time.
species shifts, resistance, and/or changes in pest’s tradition- C Chemical fallow is not as effective at
al habits that have resulted in yield losses. Proper application breaking weed, disease, and insect cycles
of rotational planning can increase yields, reduce costs, and as are black fallow, cover crop, or produc-
tion of a properly chosen crop.
improve soil health and fertility. These positive benefits affect C Rotations should be sequenced to make it
whole farm economics by reducing weed, disease, and insect easy to prevent volunteer plants of the pre-
pressure and resistance; spreading workloads to reduce fixed vious crop from becoming a weed problem.
machinery and labor costs; providing more optimum planting C Producers with livestock enterprises find
it less difficult to introduce diversity into
and harvesting timing; and diversifying income and spread- rotations.
ing weather risks. Failing to match natural systems has caused C Use of forage or flexible forage/grain
much of the environmental issues we face in US agriculture. crops and cover crops enhance the ability
to tailor rotational intensity.
It is over-simplistic to classi- C Livestock make using rotations with
fy rotations as good or bad, perennial sequences easy. It is probably
but rather rotations have not possible to be sustainable over long
periods of time without using perennial
differing characteristics in plants in the system.
terms of their impacts on C Crops destined for direct human food
various aspects of the crop use pose the highest risk and offer the
highest potential returns.
production system used. C The desire to increase diversity and inten-
Designing appropriate ro- sity needs to be balanced with profitability.
tations is a mix of art and C Soil moisture storage is affected by sur-
science. Since all aspects face residue amounts, inter-crop period,
snow catch ability of stubble, rooting
(agronomic, environmen- depth characteristics, soil characteristics,
Photo by Doug Steffen must be considered simulta- C Seedbed conditions at the desired seed-
precipitation patterns, and other factors.
tal, economic, engineering)
ing time can be controlled through use
neously, a systems approach
of crops with differing characteristics in
and architecture.
situation, there will be a
When diversity cannot be easily added to is required. For any given regard to residue color, level, distribution,
the cash crop rotation, consider adding it range of rotations that will C Rotations that are not consistent in ei-
through a diverse multi-species cover crop be appropriate and within ther crop sequence or crop interval guard
against pest species shifts and minimize
mix. This mix of vetch, peas, cowpeas, the probability of developing resistant,
barley, oats, millet, sorghum, brassicas, this range rotations will tolerant, or adapted pest species.
buckwheat and sunflowers does just that! have differing characteris-

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