THE RESOURCE: PROTECT AND PRODUCE
MICHAEL ZOOK
BEACH, NORTH DAKOTA
SOIL - OUR MOST PRECIOUS AND FRAGILE RESOURCE.
About March of every year I would start to get that horrible gut feeling that any day now a typically late winter, high-pressure system would roll through Golden Valley County with three days of strong gusty winds sending my black fallow fields into the atmosphere. Once the fields started blowing, there was very little we could do. Often these fields would continue blowing with every front that passed through until we finally established a crop canopy.
Knowing all the while that the few inches of precious topsoil were in jeopardy. Golden Valley County soils are predominantly silt loams and are very shallow with only 3" to 4" of topsoil. Unprotected silt loam soils are highly susceptible to wind and water erosion. Our annual average precipitation is 14".
Soil erosion is the major source of pollution in our area and soil erosion could carry agricultural chemicals and fertilizers. Reducing erosion is the single most effective way to lower sedimentation and contamination of surface water. By taking control of this issue and effectively dealing with it, may help us to avoid more costly environmental legislation and restrictions. The tools of the farming trade are in place to cut soil erosion to a bare minimum. The first step is that land users need to be concerned with the soil resource and want to make a change from black farming to a high level of residue farming, 40% ground cover or better after the fallow season is a reasonable goal.
The 1985 farm bill stipulates that producers who crop highly erodible soil must develop and apply a conservation plan to be eligible for USDA benefits, it must be implemented by 1995, four years left to accomplish the job. Zero Till is a very practical and affordable means of meeting conservation compliance requirements. The Zero Till System is in place, proven and reliable.
MANAGING THE SYSTEM
Since we cannot control the weather and political whims that determine our market price, we must control the variables that can make the most impact on our yields. The Zero Till System has several steps that must be followed, They include:
1.) Residue Management
2.) Fall Weed Control
Not following these steps can result in crop failure. Every mistake that we as producers make, whether it be from moisture loss to tillage, to improper seed placement, has a cost. This cost comes off of our bottom line. Zero Till requires future planning. Scout fields in advance to assess present and potential weed problems. Small and overlooked mistakes suddenly become big problems. Scouting fields for insect and disease problems and taking preventative measures to counter these problems before they occur are the least costly and most effective. Control of disease and insects in Zero Till is dependent on rotations, resistant varieties and available fungicides and insecticides. PAY ATTENTION TO DETAIL!
RESIDUE MANAGEMENT
Massive accumulation of residue with continual Zero Till Farming has not occurred, by switching to semi-dwarf wheats we have eliminated some trouble spots. Upright crop residues are surprisingly brittle by spring and present less problems with seeding equipment than matted accumulations of crop residue.
Straw and chaff spreading equipment is a high priority for Zero Till, it helps to alleviate poor performance of the drill through the chaff row. A poor job of crop residue spreading usually results in cooler and moister soil conditions under the chaff blanket, creating a suitable environment for disease pathogens. Plant growth may be weak with spindly plants, possible allelopathic reactions and later plant maturity.
Consider this, a 30 foot header on our combine as it passes through the field with a 35 bushel wheat crop cut at a height of 10 inches. This yields .055 pounds of straw per square foot. For every linear foot forward we collect 30 square feet of crop residue in our combine, which equals 1.65 pounds of straw. Ideally, we should return the initial .055 pounds of straw to its origin. With a six foot spread we end up with .275 pounds of straw per square foot
directly behind the combine (five times the amount). Although this does not sound like much, it creates a finely chopped up blanket of chaff two to three inches thick. This poor management of the crop residue is an ideal situation for diseases, etc. Standing crop stubble effectively holds snow where it falls and traps drifting snow from adjacent unprotected fields, which is one of the greatest advantages of Zero Till in an annual cropping system. Standing stubble aids in the water management program.
A snow blanket between 3" to 4' will maintain soil temperature at 32 degree F at a 2"depth with little bearing from the ambient air temperature. This provides adequate protection for fall seeded crops from winterkill. Snow falling on unfrozen ground is perhaps the most efficient way of getting water into the soil profile. Soil temperature on Oct. 30, 1991, in crop stubble at a 2" depth was 34 degrees with a 6-1/2" snow blanket, on black fallow, soil temperature at a 2" depth was 26 degrees with 1/2" snow cover in the furrow. Blowing and drifting snow across unprotected fields is very abrasive and is also a serious form of soil erosion as well as a waste of valuable moisture and a major cause of agricultural pollution in our rivers, streams and drainage ways.
By leaving crop stubble in place it can also help prevent other problems. Blowing and drifting snow fills the ditches, blocks roadways and highways, and reduces visibility. Have you noticed during a winter storm that visibility improves and snow on the roadway decreases as you pass a field with crop stubble intact? Shelterbelts and farmsteads, next to unprotected fields, collect huge snow banks that hamper livestock feeding operations, kills wildlife and most is ultimately lost as run-off.
BORDER SANITATION
When we were beginning Zero Till, a serious problem was encroaching grasses on field borders, left unchecked, quickly spread over the entire field. Our herbicide burn down rates were not effectively controlling these grasses and during harvest were being scattered throughout the field. To combat this problem we now mow field borders to prevent seed spread and in October occasionally make a 20 foot, one quart glyphosphate application on grassy
borders, being careful to avoid spraying beyond field borders as unseeded areas quickly turn into weeds.
FERTILITY
Soil testing in the fall has become an important step in our fertilizer management program. Since 1983, on several fields the soil tests have indicated a .1% increase in organic matter. Soil structure and tilth have steadily improved. By using a realistic yield goal it gives us a good idea of our fertilizer requirements and enables us to participate in pre-season discounts. Over-application can be ineffective and contribute to water pollution. Under-application will reduce yields and stressed plants may become more susceptible to disease. We test each field yearly and keep field records of amount and types of fertilizer applied.
EQUIPMENT
We have always felt the most important piece of equipment on our farm is our seeding equipment - it establishes the foundation for the entire crop year. Seeding equipment should be able to handle residue, provide excellent seed placement and excellent seed-to-soil contact. Spraying equipment must be maintained so it is trouble-free, given the narrow application window of most post-emergent herbicides. Wind screens and deflectors may prove to be of value to help minimize drift and allow timely chemical applications. A good marking system has proven to be a necessity as it alleviates skips, over-application and much frustration. A foam marker, tramline or following drill rows may be effective. By moving towards Zero Till, we have eliminated one 4WD tractor and we sold a newer tractor and replaced it with an older model. Making payments on expensive equipment sitting in the quonset depreciating are an expense we don't need. We have cut our dependence on fuel by 55% by reducing our tillage operations.
CHEMICAL FALLOW
Chemical Fallow has also been an excellent form of wind erosion control on our silt loam soils while eliminating tillage operations and saving our most limiting factor: moisture. By the end of the 20-month fallow season, water erosion can become a factor on chemical fallow fields with 6% or greater slopes and snow catch is not always the best due to residue degradation. We used to till the borders of our chemical fallow fields to eliminate drift into growing crops, but after several hard rains it became apparent that while the rest of the field repelled the hard impact of the raindrops, the tilled borders acted as a brake and washed them to tillage depth. We now wait for the right wind to spray next to the crop.
In the past, a major problem for us with conventional tillage has been proper seed placement. The depth of the tillage implement was generally where the seed was placed. Since we have gone to Zero Till our seed placement has greatly improved. Shallower seeding (about3/4" to 1" deep) into a moist seedbed offered by Zero Till allows quick emergence. Another advantage of Zero Till became quite apparent this spring after several very hard, splashing
rains during seeding. The drill ridges in the conventional tilled fields were washed into the seedfurrow, burying the seed about 4" deep. We went over this field with a rotary hoe as soon as possible, the final result was a 50% stand reduction and increased weed pressure. We had seeded a Zero Till field directly beside this conventional tilled field one day later, we had an excellent stand with no crusting or soil erosion with a 12 bushel better yield. The conventional tilled field should have been reseeded, but as we were getting late into the season it was not a viable option. Rotary hoeing or reseeding is another expense not incurred by Zero Till.
CONCLUSION:
Erosion is not a cash cost that will show up on this year's or next year's balance sheet. Yet it definitely represents a costly mortgage on our lands future crop production potential. Zero Till farming can reduce water and wind erosion by 90% or more. The soil itself is a farmer's and independent nation's most valuable economic asset. The soil is my factory, if I handle it with care I'm sure it will work for me and future farmers.