by David Rourke and Andrew Hargrave

The Conservation Tillage Productivity Centre

Improvements in seeding equipment with precision placement of seed and fertilizer, improved herbicides, lower cost of Roundup and concerns for moisture conservation have all contributed to the movement toward direct seeding into stubble. What happens to the soil ecosystem in direct seeding and what factors must one consider when choosing a rotation in a one pass system?

Certainly, soil structure will change with the lack of pulverization. Microbial activity will increase. Soil moisture availability and soil moisture holding capacity should also increase. Weed dynamics as well as disease pressures will change. So how can one economically manage these changes? There is no substitute for good management. By monitoring the changes in the field, a good manager can alter farming practices to meet the new obstacles and also take advantage of the benefits of direct seeding. One of the most important considerations is to adjust crop rotations to take advantage of improved soil conditions and also to manage weeds and diseases. One might also add that weeds and diseases which do not exist need not be controlled! Of course, the rotation must be economically sustainable, but at the same time must maintain soil quality and limit weed resistance and disease accumulation.

What are some of the factors which should be considered when choosing a rotation? First, one has to consider the limiting factors in the cropping area such as frost free days, growing degree days and available moisture. 2) the potential yield and market value of that crop, 3) the cost of inputs to grow a crop. 4) Are herbicides available to control your weed problems in a particular crop? 5) What diseases have been appearing in a particular field? 6) Will present seeding and harvesting equipment be adequate for the crop and residue? 7) What are the moisture and nutrient needs for the crop? This is not an exhaustive list, but wilt help to narrow down the choices for a good rotation.

1) Cropping region and soil type:

Growing crop varieties which are compatible to the growing region is important. Frost-free days, growing degree days and available moisture are important considerations A further consideration might be lower soil temperatures in fields with higher residues Seeding into this situation with a low disturbance drill may not provide an adequate microclimate to provide the soil temperature needed for germination and may delay emergence and ultimately shorten the potential growing season (Figure 1). A higher disturbance drill will allow the disturbed area to warm up more quickly, thus minimizing this problem

Frost -free days and potential growing degree days will be a limiting factor when considering potential crops to insert into a rotation. In shorter growing season areas such as Riding Mountain, it is important to choose more frost resistant crops such as peas or shorter growing season crops such as Polish canola, oats and barley (see Appendix 1). In longer growing season regions such as south central Manitoba, growing season is not generally a limiting factor for crops such as corn, sunflowers and sugar beets.

If soil moisture is a limiting factor, direct seeding becomes more important. Snow trap in stubble over winter becomes much needed soil moisture at seeding. In the Minto, Manitoba area, there was as much as 3 V2" more of available moisture in zero till after wheat compared to conventional till at seeding in the top 4' of soil. Even a fall banding pass will reduce available moisture at seeding. The extra moisture in Zero till allows for shallower seeding and therefore results in quicker emergence and a more vigorous crop. To further provide soil moisture, heavy residue crops such as barley) oats and CPS wheat should be included in the rotation.

On the other hand, if too much soil moisture is a problem, such as in the Red River valley, more crops with less residue cover should be included in the rotation. Crops such as flax (when baled), peas, canola and lentils when managed properly provide little soil protection, allowing the soil surface to dry in the spring. A further option would be to fall band to remove excess water.

2) Potential yield and market value:

Of course, $ and sense are important when considering crops in a rotation. It is important to have a flexible rotation to be able to take advantage of market trends. Naturally, in regions where crop choices are not as limiting, the options are far greater. Once a list of possible crops to be grown has been established, the next consideration is to maximize the potential return. 100k at the market value of the different crops and the potential yield of these crops in your area. This has to be looked at in the longer term as well as the short term. Some land may benefit by the inclusion of alfalfa in the rotation. Although the potential return may not be as high as other options, future crops may benefit in the long run. (Work at the University of Manitoba by Dr. Entz has provided incite for getting in and out of alfalfa without breaking the soil.) On the other hand, if there is no potential market for the alfalfa hay or seed, this option may not be a viable one. In short, a rotation should be chosen which will maintain or enhance yields of future crops and bring an economic cash return in the present.

3) Cost of inputs:

The cost and efficacy of inputs should also be thrown into the economic equation. Seed treatments and innoculants, fertilizer, herbicides, fungicides, insecticides, and even combining, trucking and storage costs should be considered. The decision to use pesticides will be based on an economic decision, i.e. whether the net margin warrants the added costs. If it is anticipated that these pesticides may be needed before a crop decision has been made, this may influence the choice of crop or variety which may be used.

Fertilizer inputs in direct seeding should probably be looked at more closely. Most recommendations are based on conventional till systems. Increased moisture and microbial activity may make it more economical to use higher rates of fertilizer (away from the seed please!). At the CTPC, increasing the nitrogen inputs well above the recommended rate resulted in economic yield increases in most situations. Furthermore, a split application allows for more sensitivity to moisture conditions.

4) Herbicide availability:

Are there herbicides available to handle the antecedent weed population including volunteers? Up until now, the spectrum of weeds controlled in broadleaf crops has been limited. Roundup and Harvest tolerant canola varieties will help to reduce some weed problems at a reasonable cost. The registration of Pursuit in alfalfa and peas will help to control broadleaf weeds which were previously difficult to control.

Further herbicide considerations when deciding on a crop rotation are the need to rotate herbicides and to change timings of applications. This will prevent both the build up of herbicide resistant weeds as well as the development of new weed problems by exclusion of control.

Over the years Zero tillers may have been relying more heavily on Group 1 herbicides for grassy weed control. It appears that Group 3 herbicides (Advance, Edge, Rival, Treflan, Trifluralex, Fortress and Trifluralin) and Group 8 herbicides (Avadex BW, Avenge and Fortress) are an ideal fit in zero till, reducing the potential for Group 1 resistance (Figure 4). Considerable positive data has been developed on surface application of these herbicides in a zero till system. Rotate herbicides in order to control different problem weeds every year so that a particular weed does not get neglected, creating problems down the road. If a particular weed is a problem and can best be controlled in a particular crop, then using that crop may be necessary to set the weed back enough for other crops in future years. Varying the seeding dates and harvest dates, the use of pre seeding and pre harvest herbicides will help to control different weeds at more vulnerable times.

The use of a very competitive crop like barley periodically in the rotation will help to suppress weeds with minimal or no herbicide inputs.

It is essential to be able to control volunteers from the previous year in a subsequent crop.

5) Diseases:

What diseases have been appearing in a particular field? How many years must a crop be excluded because of root rots, septoria, black leg, sclerotinia, ascochyta, etc.? What can be done to reduce these diseases? Some work has been done by Dr. Cook (Washington St.) and Dr. Bailey (Saskatoon) which has shown that leaving soil undisturbed, may reduce the viability of some disease inoculum. Despite this, it is still advisable to rotate crops. Work at the CTPC has shown that seed treatment and fungicides were more effective in zero till wheat when grown every other year than in successive years (Figure 5). There was a definite economic advantage to reducing the number of years of wheat (Figure 6). There was also evidence that wheat was more responsive to fungicides in a more diverse rotation. It is recommended that crops susceptible to sclerotinia should be grown once in 4 years. There is work in progress in Minto which is looking at shorter rotations of lentils and peas in zero till. Avoidance of consecutive annual crops and crops with like disease inoculum will help to reduce disease buildup. Choosing disease resistant varieties would also be advisable when a disease inoculum may be present.

6) Seeding equipment:

Some crops such as corn require special seeding equipment. A purchase of new equipment or conversion kit to adapt existing equipment may be required at a cost to include some crops in the rotation. Also, special harvesting equipment may be needed for some crops such as a pick-up for peas to either make harvest possible or more efficient. Seeding into heavy residue may be a problem for some drills. For example, seeding canola into barley stubble at V2" with a ZT disc drill. There may be problems with hairpinning. Another factor may be fertilizer placement. Inherent with direct seeding is the need to precision band fertilizer away from the seed. Seed placed fertilizer is risky especially with crops such as canola and flax. With sensitive crops a better choice may be to broadcast the fertilizer.

7) What are the moisture and nutrient needs of a crop?

It may be an advantage to use a heavy nutrient and moisture user following a less nutrient taxing crop. In the case of a legume crop or perhaps a forage crop such as alfalfa, nitrification may take place for two years allowing for two successive crops of heavy nitrogen users following these crops. Fertilizer inputs should still be used, but perhaps at a reduced rate.

In areas of moisture restrictions, it may be necessary to alternate heavy water users with crops not as demanding. This may be flexible depending on fall and winter moisture.

There is no magic rotation for everyone! To choose the rotation (or rotation options) which is right for you it is important to take into account climatic and soil restrictions, cost of inputs, weed and disease pressures, machinery capabilities, economics and market conditions. Alternating crop types and herbicides is always a good idea where possible. Direct seeding has many potential pitfalls and opportunities. It is up to you to act on them! Appendix 1. Days to maturity for some crops grown in Manitoba and Saskatchewan

Crop Days to Maturity

Barley 60 - 90

Polish Canola 73 - 83

Buckwheat 80 - 90

Yellow Mustard 80 - 90

Oats 85 - 95

BrownMustard 85-95

Flax 85 - 100

Lentils 85 - 100

Wheat 90 - 100

Field Peas 90 - 100

NavyBeans 90-100

Coriander 90 - 100

Argentine Canola 92 - 102

Black Beans 95 - 105

Canary Seed Grass 95 - 105

Fababeans 105-115

Corn (Grain) 110-120

Sunflowers 120 - 130

Sugar Beets 120 - 140

Source: Agricultural Climate of the Eastern Canadian Prairies, 1992.

WAGNER FARMS - SITE SPECIFIC EXPERIENCES

Gary L. Wagner

A.W.G.Farms Inc.

Route 1 Box 123

Crookston, MN 56716

(218) 281-7905

OVERVIEW

Global Positioning System (GPS) and Site Specific Farming: if these aren't household words yet, they soon may be. GPS Is poised to revolutionize today's farming methods. It offers for the first time a way to precisely measure your position anywhere on Earth and Site Specific Farming may become a more precise way to farm.

For years we have measured the characteristics of our fields. We have looked at parameters like soil composition, moisture levels, nutrient concentration, and crop yields, but have had no way to pinpoint the data to specific locations in the field. Field characteristics are not uniform over large areas, and in fact, would we like to study those characteristics right down to a resolution of a few yards.

In 1993 and 1994 we started to experiment with a yield monitor and GPS equipment to accomplish site specific information on our farm, I will cover the equipment used and information gathered in this two year period. I also will try to interpret some of the results, which at best, is an educated guess.

OPERATION

A.W.G. Farms Inc. is a small grain, sugar beet, and sunflower operation, located in the northern region of the Red River Valley of Minnesota; this is approximately 22 miles due east of Grand Forks, North Dakota. The farm principle operators are three brothers, Wayne, Daryl, and myself Gary. We farm approximately 4500 acres; 800 acres of sugar beets, 100n acres of sunflowers, and the balance to Spring Wheat, Durum, Barley, and Soybeans.

The farms labor resources totalling 14 men during the peak harvest times, and 3~5 men during the spring and summer operations.

The term site specific farming was a new term presented to us in the summer of 1993, when we were approached to use a pro-type combine yield monitor. P.C. Robert, of the University of Minnesota, St. Paul, contacted us several weeks before grain harvest, with the possibility of trying a yield monitor system. We accepted the invitation, and were introduced to Ted Macy of Application Mapping, Frankfort, IL.

Ted Macy is the principle software developer and owner of Application Mapping, that uses the GPS (global position satellite) system, grain yield monitor (Ag Leader 2000 from Ag Leader Technology, of Ames, Iowa), and computer, to generate yield maps. Ted came to our farm at the start of harvest to help us calibrate the yield monitor and complete the work on his software program.

We installed the monitor on the combine, a lap top computer in the cab, and GPS equipment both on farm and combine cab. The original thought was can this be possible," but in a very short time we became believers.

YIELD MONITOR

The yield monitor has three major components; yield sensor, moisture sensor, and monitor control box. It has the capability to:

Continuously measure and display yield, moisture, speed, grain flow, and acres covered per hour.

Calculate, display and record average yield, average moisture, area, distance, wet bushels, dry bushels, harvest date and time for each load, as well as field totals

Record field and load names.

Records a total of 976 loads.

At the season end, down load all information collected from the monitor during the season, to a computer, and then to paper.

GPS EQUIPMENT AND INFORMATION

The GPS equipment has three components'. satellite radio receiver, differential radio broadcast, differential radio receiver. The GPS system is a set of 24 satellites circling the Earth. They broadcast a precise set of radio signals and time references. The orbits of the satellites are designed so that there will be at least four in view over any one point on Earth at all times. A specially designed radio receiver detects these signals and, with its internal computer, measures the distance from itself to each of the satellites from which it receives signals.

Once these four or more distances are known, along with the exact point in space where these satellites are located, the receiver can calculate exactly where it is on Earth, usually within 300 feet. The error margin is due to several factors, mostly by the US Department of Defence (DOD), which controls the satellites. The GPS system is 50 accurate, and provides such good global coverage that the DOD decided to purposely induce errors into the radio signals to prevent foreign powers from utilizing this asset in times of war. Thus SA, (Selective Availability) was developed and it affects all civilian GPS receivers, and creates most of the 300 foot error.

This 300 foot error is not acceptable in a agriculture application, a more accurate form of GPS is need. Differential GPS (DGPS), was developed to over come this problem. In DGPS, a GPS receiver sits still at a known location and continually measures its position based on the signals it receives from the satellites. Since it knows it is sitting still, all measured positions occur inside a 300 foot circle, and are recorded as an error to the actual position.

This error is then broadcast on a radio to a separate GPS station on the combine. That unit measures its position according to the satellites, applies the error signal sent from the reference station over the radio link, and can fix 'Is position in the field to with in a foot.

Ted Macy's job was to tie the two technologies together. The GPS information and yield information from the yield monitor are combined and stored on a computer disk to help generate accurate crop yield maps.

SUGAR BEET YIELD SENSOR

In our operation, sugar beets is the major cash crop. All resources are focused on raising the best possible quality crop. Unlike a yield monitor for a combine (small grain industry), the sugarbeet industry is minute. Developing a yield sensor for this type of harvest machine has to come the Industry itself.

In 1994 Vern Holirnan, Extension Ag Engineer, North Dakota State University, approached us to develop a yield sensor for our sugar beet harvester. Vern received a grant from the Sugarbeet Research and Education Board of Minnesota and North Dakota, to work on this project.

A proto-type sensor was built. May obstacles needed to be overcome, especially how to control the vibration produced by the machine. Vern was very successful, and is planning to work with industry to further develop the sensor.

In cooperation with other individuals that are working on sensors for potatoes, this sensing technology will soon be a reality.

DATA ANALYSIS

For this presentation I will use one field and attempt to analyze the information that we gathered for the two years. Some of the tool used:

Grain yield maps (2 yrs)

grid soil test information (2 yrs)

soil types maps

topographical map

OTHER BENEFITS

Besides gathering information on yield information other benefits are;

Spot a device that works In conjunction with the yield monitor and GPS system to record problem areas such as;

l. weed problem areas

2. drainage problems

3. rock piles

4. or any other field problem areas

With GPS soil test locations can be recorded to repeat fertility test.

With both the Grain Sensor and Sugarbeet Sensor we will have the ability to determine the amount of weight stored on a truck. This will help to maintain "legal truck weights for road conditions.

Determine the need for fertilizers and chemicals. Hopefully will reduce the overall input costs.

Other benefits can be achieved by using your imagination.

SUMMARY

For many years industry indicated that computers will make farming more profitable. Up to this time this was not true. If the farmer had an accounting back ground he could do his own financial record keeping, saving the price of an accountant. But all information had to be typed into the computer via the keyboard. Finally, we can obtain useful information about our farm "on the fly' or at the same time we are doing our work. This new technology will greatly increase our knowledge of the land we farm. But the more we know, the more questions we have. Crop consultants or people specializing in interpreting this information will be needed. The future is beginning NOW, are you ready??