For me, choosing the proper crop rotation is the most important decision a grower can make for their operation. It will directly affect your bottom line, weed and disease cycles, and how your farm and soil will perform well into the future.
We’ve spent more than 20 years developing a crop rotation that fits our semi-arid climate and growing season. We’ve changed the crops we grow in this rotation, but have based the majority of the rotation on a cool-season grass (winter wheat) a warm-season grass (corn or proso millet) and a cool-season legume — either chickpeas or, more recently, field peas.
I think there are some important considerations when you design your crop rotation for no-tilling.
On dryland acres I think the biggest challenge is developing a rotation that fully utilizes the moisture you can expect to receive and produce profitable crops with this moisture. You have to temper your expectations of what you think you can grow with the no-till system.
The challenge is to realistically design a rotation that fully utilizes the moisture you receive without failing within the rotation too often due to low rainfall. You have to design a system that occasionally fails during the dry years, so that during the normal and above-normal rainfall growing seasons you have good success in utilizing the moisture you receive. The key point is to not fail too often.
I also believe we have to have a fallow period before planting the next crop. We found that trying to produce winter wheat without some fallow period prior to seeding our winter wheat really hurt our winter wheat yields.
I think we need to produce as good a winter wheat crop as possible to succeed in continuous no-till crop production in our growing environment. Winter wheat really produces the residue that is required to make the whole rotation succeed.
The continuous crop rotation that we’ve been using for the past several years on our dryland acres has been a rotation of winter wheat, corn and field peas. I think this has been a good rotation, with 2/3 of it being high-residue crops like winter wheat and corn.
I also think this rotation is good because 2/3 of our rotation needs moisture to produce grain in the same time frame that we generally have our wettest months — April, May and June. The field peas and winter wheat require moisture for grain production during these months.
The dryland corn takes advantage of any summer precipitation we may receive and can produce high yields if we receive normal or above-normal rainfall in July and August.
Dryland corn can also fail when the summer rains don’t come, which happens somewhat frequently. Dryland corn production is definitely the most inconsistent part of our crop rotation. We usually get enough rain that the corn crop looks good, but we often fail because we don’t get enough rain to produce high-yielding grain.
I think proso millet would be a good substitute for dryland corn in this rotation if you live in an area that receives less than the 15-inch average precipitation that we receive on our farm.
This rotation of a cool-season grass with winter wheat, a cool-season legume with the field peas, and a warm-season grass with the corn or proso millet, is a good rotation for our area for grain production farms. It provides enough diversity that weed and disease problems that can occur in monoculture production aren’t much problem with this diverse rotation.