Great Bend Tribune
Published January 15, 2017
Part I – Soil Testing
As this is being written, weather forecasts are calling for a wintry mess including ice. Here’s hoping everyone is safe and sound with electricity. This promises to be a challenging year for crop and livestock producers with commodity prices. The next few weeks will focus on several items that can improve efficiencies by minimizing costs and optimizing output. The term “optimizing” output is used because maximizing production seldom results in maximizing profits per acre. Today’s topic concerns the value of soil testing for pH and nutrients.
Fertilizer costs make up a major portion of input costs, especially for grass crops such as corn, wheat, and grain sorghum. Soil pH plays an important role in many aspects of crop production. While soil testing has become much more common over the last two decades, there are still producers who seldom if ever soil test, some who occasionally soil test, and some who regularly test but ignore certain tests. So what are we discussing with soil testing?
With precision farming technologies, grid sampling, associating a group of samples with specific locations to develop maps of nutrient variation are possible. Depending on the extent of field variation, they may be of value. A producer won’t know till they test. It is possible to decrease fertilizer use and variably apply nutrients to optimize yields. As a side note, with technology such as Green Seeker, nitrogen application rates may be determined on the go and variably applied without a soil test. The other option is bulk sampling where a group of samples is collected across a field. This may be adequate if the field is fairly uniform and is better than nothing. And if a producer has completed a recent sampling, it may not be necessary to sample for many nutrients and pH every year depending on the results and the keeping of adequate yield records to determine nutrient uptake.
What testing is most beneficial? If you farm in higher pH soils you can ignore this but if you farm many of the soils in the southern part of the area, especially sandier soils, pH is critical to gauge soil acidity. Low pH soils can result in significant yield loss for a number of reasons, including:
- Legumes like soybean and alfalfa won’t nodulate and be nitrogen deficient.
- Many herbicides are rendered ineffective at lower pH resulting in decreased weed control.
- Nutrient availability is affected at pH extremes which can result in decreased yield, plant susceptibility to diseases and stress, and in certain instances toxic level of nutrients and other compounds.
- Acid soils lose their ability to hold onto cations such as potassium, zinc, iron, calcium and magnesium which makes fertilizing more difficult.
- Low pH also favors plant diseases directly and indirectly. And it changes the overall soil biological part of the ecosystem which can have negative effects on plant growth.
- Certain crops root systems are extremely sensitive to aluminum which can be present at low pH and significantly damage root systems.
- Low pH can be corrected with lime which while not cheap pays for itself. And for the beneficial effects of liming to occur, you need as much time as possible between lime application and planting, preferably nine to twelve months.
Part II – Soil Testing Benefits
While off in the timing and location a bit, meteorologists were correct about the storm last weekend. Hopefully as you read this everyone’s power has been restored. This storm was unusual for the area as icing this heavy isn’t typical and for the amount of precipitation. Typically in January the area receives less than an inch of liquid precipitation. Typical reports here and towards Southwest Kanas were well over an inch and in many cases well over two inches. This is valuable moisture for the wheat crop and the drought ratings should ease significantly. Last week’s column discussed soil testing and correcting acid soils to improve efficiency. This week, what are the possible benefits of soil testing for fertilizers?
- The most obvious efficiency is not spending money on fertilizer that isn’t needed. And making sure fertility is adequate for the yield goal. If you have developed a soil map for a given nutrient, say phosphorus (P), you can variably apply through precision application that P to where it is needed and not where supplies are adequate. If you take it a step further, you can identify through yield mapping the high yielding areas of fields and those that no matter what you do possess limited yield capacity so additional fertilizer is a waste of money. You can then focus fertilizer dollars where they will do the most good.
- Low crop prices are the result of more supply than demand. Even so, a way to improve revenue and optimize the value of input costs is to optimize yields per acre. The greater the per acre yield for a level of total input costs, the less your per bushel costs are. This is where paying attention to nutrients like sulfur and micronutrients is important. A few pounds per acre of Zinc Chelate can mean the difference between 200 bu per acre corn and 220 bushel per acre corn. A sulfur application can dramatically increase wheat yield and wheat protein levels.
- Plant health is optimized through proper plant nutrition. Plants are more vigorous and unstressed plants are better able to compete with weeds and resist other pest pressure such as diseases and insects. Additional the right fertilizer program aids crops in overcoming environmental factors such as drought and high temperatures. Crops with proper fertility mature properly, not early or not late. They possess the best test weight possible given the environment.
And there are other benefits including protecting the environment. Soil testing isn’t necessarily cheap but a proper soil testing program more than pays for itself both in terms of input costs and revenue.
Part III – Water
Today we will focus on efficiency in crop production and water. The latest Drought Monitor report ties into this. As of this past Tuesday, our area is no longer even moderately dry except for a sliver of northern Barton County and extreme western Rush and Pawnee Counties. Moderate drought has retreated to the western quarter of the state, however, there is still a sliver of severe drought in Southwest Kansas. A large part of efficiency is effective conserving and using resources. Water is certainly a key resource so how do producers efficiently use water to optimize possible crop production? This is by no means a complete list.
- Hybrid/Variety Selection – It is critical to select the proper cultivar for conditions. This includes maturity, cultivar characteristics for soil and climate, resistance to pests, and yield potential. Response under irrigation is also important.
- Conserving soil moisture – Every effort must be made to not lose soil water through evaporation and/or weeds. This means minimizing or where possible eliminating tillage. Surface residue accumulation helps facilitate this.
- Proper fertility – A balanced fertility program with a realistic yield goal serves two purposes. First it allows optimal plant growth for conditions resulting in efficient water use. Secondly, it prevents over fertilization and helps prevent wasting water on unneeded vegetative growth. It has the added benefit of helping control weeds through vigorous crop growth.
- Cultural practices – Planting as early as possible for summer crops or not too early for fall-seeded crops. Selecting the appropriate row spacing and seeding rate are two ways to improve water use efficiency.
- Pest control – Controlling weeds, insects, and diseases has a major impact on improving efficient water use optimizing yield. Anything that minimizes plant stress will. This can be accomplished through genetics, planting date, crop rotation, chemically, etc.
- Irrigation equipment – With irrigation it is important to make sure equipment is in proper working order. Check to make sure the proper nozzles are in place. Where appropriate consider pressure regulating and renozzle to improve efficiency.
- Irrigation scheduling & amount – With irrigation it is critical to monitor crop growth stage, evapotranspiration, and soil moisture status to neither over or under water. Many of these programs are available and K-State has one that is free. Also important is matching irrigation intensity to soil infiltration capacity.
Conclusion
Today we will wrap up this brief discussion regarding crop production efficiencies. First, we discussed soil testing and proper fertilizer recommendations. Then was the discussion of efficiency and water, including irrigation. We will wrap production efficiency up this week with a few more thoughts.
- As farming operations, conditions and resources allow, develop as diverse a crop rotation as possible. This helps spread agronomic and economic risk. In addition, it will allow for a decrease in tillage, reduce pest pressure, and should under normal conditions increase crop yields with the same level of inputs or allow for the same level of yield with lower input levels.
- Carefully study and then select the best possible hybrids/varieties for your operation and long-term growing conditions. For significant acreage, select several adapted cultivars. Spread risk by staggering planting dates a bit and/or through cultivars of slightly different maturities.
- Do everything practical and within the power of the producer to eliminate/avoid stress. This includes proper fertility, pest control, planting date, crop maturity, etc. You can’t eliminate stress but you can minimize stress through cultural practices ranging from a balanced fertility program to proper seeding rates and pest control.
- Split fertilizer applications of nutrients like nitrogen. Be patient. By splitting nitrogen applications you achieve to efficiencies. First, you can evaluate the crop and fertilize accordingly. Second, you minimize the chance of fertilizer loss and help insure the crop will have nitrogen when it needs it to optimize yields.
- Monitor crops and then monitor them some more. And not from the pickup. Don’t be afraid to take plant samples for nutrient analysis. Check for diseases and insects.
- Keep detailed records of everything by field. This allows producers to evaluate and adjust. If possible develop accurate yield maps over years by field to identify the high yielding areas that could benefit from increased inputs and those areas that are low yielding and not only won’t benefit from increased inputs but may allow you to decrease inputs without affecting yield.
The overall idea here isn’t to equate efficiency with not spending money but spending it as necessary and wisely. Efficiency isn’t aiming for maximum yields or purposely lower yields but to be realistic and flexible in cropping decisions to take advantage of better than expected conditions and conversely to not be hurt agronomically any more than necessary by worse than average conditions or unexpected events.