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ISSUE 16   August 24, 2000


PRECISION FARMING

    Adoption of precision farming continues in North Dakota despite low crop prices. In fact, adoption sometimes progresses because of low crop prices. Precision farming can be adopted at many levels. Consider the status quo – single yield records for farms, and sometimes landlords; basing fertilizer rates on county average or neighbor soil tests; composite soil tests; whole field treatment for weeds and other pests.

    Adoption of any management technique that progresses towards a better management of fields or parts of fields is an adoption of precision farming. Simple advancements could be soil testing individual fields, recording yields of individual fields separately and keeping better records of inputs on each field.

    Once a basic understanding of the performance and "personality" of each field is reached, a grower may want to move to a higher level of understanding. With the expense of fall applied wild oat herbicides, a grower may want to "flag" wild oat spots at harvest using GPS. Because of the recent descrambling of GPS signals by the Department of Defense, it may be possible to use a high quality, low price sports GPS unit to record these points. To see if it is possible, borrow a unit from a local fisherman and flag a few spots in a field. Come back in about an hour and see how close to the flags navigating to the coordinates will be, then come back a day later and test again. If the coordinates are within 20 feet, it may be close enough to use this type of GPS
unit to relocate wild oat areas.

    Another simple and inexpensive tool is landscape based soil testing. A composite soil test uses 30 soil cores to represent a field. With landscape-based soil testing, a hill-top, slope, and depressional area soil sample, each consisting of about 10 soil cores, are taken to represent major nutrient zones in the field. The result is a measure of variability within the field based on landscape, a conformation of whether a soil test is high or low, and direction as to how much fertilizer to apply to parts of the field if practical. Some growers do not soil test because they do not believe the results. However, sampling by zone gives much more confidence in the values because the possibility that all three numbers have been skewed by an errant core in the "hot spot" if greatly reduced.

    The ultimate movement to precision farming is the use of an agriculturally designed GPS unit that can be moved from a combine yield monitor to other pieces of equipment such as an ATV for weed/pest locating or variable rate fertilizer or pesticide applicator. Use of these tools enables precision farming to be accomplished with less in-season labor and record yields and management in space and time. It allows testing of fertilizer rates and pesticides for effects on yield, for better guidance in future decision making. It provides excellent records to share with financial partners and landlords.

    For more information on precision farming, see NDSU circulars SF 1176 (1-4) through your local extension agent or on the web.

 

IF I HAD IT TO DO OVER AGAIN-

    One thing about farming that is maddening is that what you learned last year is different than what you will deal with now and in the future. But there are certain principles that remain every year and using them to manage the twists that weather give you helps to reduce overall risk and increase profitability over time.

    One theme that I heard this spring was- "Wheat isn’t worth anything, so I’m going to drop my nitrogen .. or nitrogen rate". Well, if you had to do it over again, dropping your nitrogen rate was not the way to go. Early summer rain increased N leaching, and some denitrification. When wheat is plentiful, elevators only want the best, not the mediocre. So despite not getting a really high premium for good quality wheat, the opposite is even worse- getting a high dock for poor quality wheat. The principle to follow is- if you decide to grow a crop, manage it for top yields and quality. If you plan your management for failure, you will succeed in failing.

    Nearly all of the small grain crop was seeded very early. Some of that early seeding was due to favorable weather, but some was due to ingrained panic over being rained out in 1999 and forced to seed in June. There were many fields seeded a couple days earlier than they should have been, resulting in spring compaction. Sometimes spring compaction can be softened by timely early season rains, only this year it did not rain. The soils in these fields became like concrete and did not allow the roots to penetrate well to reach the moist soil underneath. Although later rains saved some of the crop, the great opportunity to
reach higher yields was gone once the tillering decision was past. If you had to do it over again, exercise patience in seeding. The later it gets in the seeding season the less patience I would exercise, but mudding in a field in late March or early April is probably not wise most years.

    A sizable number of growers soil test, but then apply the same rate of fertilizer as they did the year before. I do not really understand this, unless somehow they have their soil tested for free. If you had to do it over again, sampling by landscape- hilltop, slope, depression- will provide three numbers instead of one and would give much more confidence in the soil test number. I think it is a lack of confidence in the number that troubles many growers, not the calibration of our soil test with yield in small plots.

    If it stays wet, sulfur levels on hilltops and eroded areas may become important. This spring, several of the trials being conducted on sandy hilltops and ridge tops, especially west-river were greener and had superior early vigor to the surrounding areas. We applied sulfur to all of our plots to equalize the sulfur rate between copper sulfate rates and the untreated plots. The sulfur appeared to make a difference between our plots and the surrounding field. Although I doubt that whole fields need sulfur for small grains similar to the needs of canola, investigating the need for sulfur on hilltops and eroded areas and applying some sulfate fertilizer on these areas with a fertilizer cart may make a sizable difference in the productivity of these areas.

    Each year, a culling process continues in soybean variety selection. This year was again a serious iron chlorosis year. Early in the season the fields were dry and green, then the rains came and nearly all of the fields in the Valley turned yellow, then as the fields dried, most areas greened back up, except for the most severe. It is a tribute to the variety selection of growers and seed companies that the situation was not worse. But there were noticeable differences between even these improved varieties, so selection will continue. Keep an eye on plots seeded on tough soil areas, and rely less on plots seeded in areas not severely affected by chlorosis.

Dr. Dave Franzen
NDSU Extension Soil Specialist


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