Concurrent Panel January 25, 1993

Fine Tuning Your System - Darrel Oech

My first zero-till seeding was done in the spring of 1982. In 1980, Southwestern North Dakota experienced a severe drought. At that time, the most common cropping practice was a 50-50 cereal grain-black fallow even blacker than normal. In the spring of 1981 it was obvious that something needed to be done to control the tremendous amount of erosion that was occurring from both wind and water. My primary reason for getting into the zero-till program in the spring of 1982, was for erosion control. With zero-till, my single goal of controlling erosion came that very first year, but it became obvious that there were many other things that needed to be done to make the system workable.

I’m not going to talk about machinery, although tremendous advances have been made in that area. I'’ not going to talk about seed-soil contact, although we all know how important it is. And I’m not going to talk about chemical control of weeds, diseases and insects. I don’t want to diminish the importance of these topics but I prefer to dwell on managing moisture, which is the theme of this workshop, and the need for crop rotations.

I would like to talk to about several things that I never thought about in the spring of 1982. In 1982 my concerns were about stopping something –namely erosion. Since then, I have focused on building something, namely the health of the soil profile. Previous to 1982, I didn’t do a very good job of managing moisture. It was easy to complain about not getting enough rain but we didn’t know how to manage the moisture that we did get.

I believe that developing crop rotations is important. Many of the disease and insect problems that we now have can be attributed to the monoculture cropping systems that we have used. Research has shown that some crops just do better following particular crops. We must adapt this research to our production systems. I believe that annual cropping systems should be developed. Mother Nature crops every acre, every year. Those of us that need to comply with federal farm programs don’t have the flexibility that we need in this area, but we can work towards it. As an example we can plant crops, not intended for harvest, that will generate residue and fix nitrogen.

More crop diversity in rotations is needed to break disease, insect and weed cycles and to reduce the chemical use of pest control. Crop residue management is the key to soil erosion control. Crop residue management is also the key to improving water use efficiencies of cropping systems. Cropping systems using deep-rooted crops like sunflower and safflower need to be included in the extended three to five year rotations with shallow rooted cereal grains to act as a safety net to reduce water and nitrogen losses below the root zone. We must learn how to understand the biodiversity of the living soil. In terms of weight, there are ten times more living bacteria in the earth’s soils, than in all the combined humans, birds and mammals, that live above the soil surface. If you add protoza, arthropods, earthworms, fungi, and algae, to the equation, the weight proportion becomes fifty to one in favor of what is below the soil surface. Learning how all theses species interact among themselves, and with others, how they are affected by environmental and human intervention, and how they affect crops will keep researchers busy for a long time. I read once that if a farmer had one million worms per acre, those worms would release four pounds of nitrate nitrogen, thirty pounds of phosphorous, seventy-two pounds of potassium, ninety pounds of magnesium and five hundred pounds of calcium. Just imagine the infiltration system that they would generate. Soil is a complex community, in and of itself. Soil is more than a medium to hold up plants. Soil plays a role in the overall cleansing of the environment. The same factors that affect air and water quality also affect soil quality, and ultimately, the food we eat.

Today, researchers are beginning to consider how nutrient levels in soil affect the nutrient levels in the crops grown there. We need to move away from regarding soil only for its productive capacity alone and think more of its ability to produce high quality, nutritious crops.

Research has shown that tillage has caused organic matter losses through oxidation and erosion. Research has also shown that organic matter can be increased about .02% per year with continues no-till cropping systems. This is like adding almost 400 pounds of organic matter per acre. This organic matter contains about 20 pounds of nitrogen, which remains bound to the organic matter, until it is slowly released by the soil micro-organisms. This slow release reduces the risk of leaching.

I think that it is important that each producer develop an annual soil testing program. Soil testing is the best tool available for controlling costs and identify nutrient needs for next year. As a rule of thumb, 2.5 pounds of nitrogen is needed per bushel of yield goal.

Problems with low phosphorus in small grains are easily confused with early season moisture stress. Low phosphorous slows seedling growth and limits development of both roots and tillers. Thin crop stands allow weeds to become a problem. It takes a vigorous root system to use a limited water supply efficiently. It also takes four roots to mature each grain head. We now have the lowest phosphorous prices that we have had for several years. Now is the time to put some phosphorous "in the bank". Find a testing lab that you are comfortable with and stay with it. I use a service from Minot that offers a sampling, analysis and recommendation package for about 73 cents per acre.

Well planned crop rotations can provide many benefits to a farming operation, including moisture conservation, improved soil productivity, erosion control and disease control.

Several conclusions on how crops influence a rotation can be made based on long term research and farmer experience.

Wheat performs best planted on fallow, second best after soybeans, and then after corn. Wheat does better following oats than other cereal grains. Wheat should follow row crops or oats and continuous wheat should be avoided. Oats can go anyplace in the rotation, except following oats.

Barley yields best on fallow and next best after row crops, and poorest after barley, oats or flax.

Flax should follow a small grain. If seeded late, it should be followed by corn or fallow.

Sunflower and safflower are late maturing, drought resistant crops which root deep and dry the subsoil. Sunflower and safflower should follow small grain.

Green manure crops, including field peas and lentils have increased small grain and corn yields, when moisture conditions are above average.