Good Decisions require Good Information

Good decisions require good information

Precision farming isn’t just for crop growers. Dairy farmers can also take advantage of this technology.

By Karl Czymmek & Jason Kahabka

Precision agriculture has been a hot topic for the last several years, as evidenced by the countless new gadgets, sensors and computer programs on the market. Many Northeast farmers have watched this evolving technology, but for the most part they’ve been skeptical. Certainly some regional farmers have given this “Midwest” technology a try, but many are still waiting for it to prove itself where it counts: the bottom line.
The time to rethink what precision agriculture can do for your operation may have finally come. The technology, research and practical experience are coming together in ways that will make precision agriculture truly useful for many Northeast producers.

What about dairying?
    As a dairy producer, how can you put these technologies to use? The answer might be more obvious than you think.
    Good management decisions require good information. Precision agriculture is simply a way to employ powerful information tools to gather data, analyze it quickly and develop a strategy that will help you meet your performance goals.
    Manure stands out as a reason to adopt a more site-specific approach to managing your croplands. Most dairy farms rely on manure to meet a portion of their crop nutrient needs, but manure application often leads to highly variable fertility patterns within a field.
    Adopting grid soil sampling helps delineate areas of high and low nutrient levels. Defining fertility patterns can indicate whether agronomic opportunities exist and, perhaps more importantly, whether site-specific management increases your options from an environmental perspective.

    In the case of the field shown in Figure 1, phosphorus fertilizer recommendations will vary minimally across the field. But since managing for P is becoming more important from an environmental standpoint, dividing this field into two separate management zones may make it possible to reduce manure applications in the highest P areas while still applying a higher rate in the rest of the field.
    On the other hand, using a single average soil sample could result in a reduced manure rate across the whole field.

Figure 1
This map shows phosphorus levels in this heavily manured field range from 13 pounds per acre on the western side to more than 70 pounds per acre on the eastern edge.

Other uses
Precision agriculture offers dairy producers, at a minimum, two other opportunities – yield monitoring and variable rate applications

Yield monitoring. For dairies with a combine, perhaps the single most significant tool currently available in the precision agriculture toolbox is the grain yield monitor. With a combine-mounted sensor, operators see and record exactly how many bushels per acre are passing through the machine at any given time. Many growers have been astonished to see yield variations of 50 to 100 bushels per acre of corn within one field.
    By linking the yield monitor with a global positioning system (GPS) receiver, operators can create a map of the crop yields across each field and easily compare yields from year to year. Often this leads to new site-specific management practices based on soil type, topography or soil moisture.
    One of the most significant benefits of using a yield monitor is the ability to do quick on-farm experiments as a way to help select hybrid.
    Commercial forage yield monitors aren’t readily available yet. Inexpensive mass flow and moisture sensors like those used on grain combines are difficult to calibrate for silage. And more complex designs are too expensive.
    Penn State and other Land Grant universities are working on refining forage yield monitoring technology. As they become available, forage crop management systems will benefit from the ability to track inventories from the field to storage and ultimately to the animal.

Variable rate technology (VRT) application equipment. Instead of applying fertilizer, pesticide or manure uniformly across a field, it’s possible to target applications in sensible agronomic and economic ways. This results in less waste, fewer environmental side effects, and improved yield and profitability, in theory.
    In practice it takes some careful planning to reap the rewards of VRT. Research shows that not all field operations can be easily managed in a site-specific way, especially in the Northeast’s glaciated soils. Potential management zones must be large enough to detect with soil sampling techniques and be significantly different from the adjacent areas in order to warrant a different application rate.
    A Cornell study investigated the feasibility of using variable seeding rates or variable hybrids within a cornfield. In each case the results showed that the differences within a field were not as significant as the differences between fields. This suggests that variable-rate planters might not be needed. But producers should consider setting up on-farm trials to experiment with optimizing their seeding rates and hybrid selections.

Uses with nutrients
    Dairy businesses may soon find that precision agriculture technologies are one of their most valuable nutrient management tools.
    Farms that fall under Concentrated Animal Feeding Operations CAFO) regulations will have to document manure application rates and timing to ensure compliance with environmental standards.
    A simple spreader mounted flow meter and GPS receiver can create accurate records of exactly where and when each load is spread. These maps document that best management practices are being followed. The same technology can automatically turn spray equipment off if an operator inadvertently drives too close to a sensitive stream, well head or residential area.
    Work done at Cornell University has shown that lime applications offer great promise for variable rate management, and many custom applicators have been doing this for years. Within one Cornell research field a pH range of 5.1 to 7.4 was observed. (See Figure 2) If the field received a single lime rate, some areas would have received too little lime and some areas would have received too much.

Remember the basics
Precision agriculture may require more soil samples, which increases costs. Instead of relying on composite soil samples for each field, a number of samples must be taken, either on a grid pattern or in each distinct soil type across the field. Generally a grid should have a spacing of less than 4 acres to capture field variability patterns. Sampling by soil type may cover a somewhat larger area.
As inconvenient as it may be, soil sampling is a very important piece of your farm’s nutrient management planning.

Figure 2
The dark areas of this map of a 24-acre field represent high pH where additional

Revolution or evolution?
Even with advances in precision agriculture, very few producers have the time, money or desire to radically alter the way they manage their cropland. And most will not transition to precision farming overnight.
But by learning what technology is available now you will be better prepared to develop both short range and long-range goals that keep your operation moving in the right direction.

Site specific management need not cost a bundle
    Most dairy producers have been applying concepts of site-specific, or animal-specific, agriculture for years. In the barn, the technology is as simple as giving that high-producing fresh cow an extra scoop of grain or extra wedge of high-quality third cutting hay. Or it may be as sophisticated as measuring individual cow activity with a pedometer or monitoring and analyzing production fluctuations with milk meters and software.
    In the field, site-specific technology may be selecting reed canarygrass for that really wet field or a stress-tolerant corn variety for the gravel lot.
    Whether managing fields or cows for differences in a high-tech, low-tech or in-between tech fashion, the question to ask is: Given the resources on this dairy, how can differences be managed to an economic advantage?
    This winter, think about where you can get more precise in your farming activities. Consider these questions and strategies:

Do you notice substantial yield differences across certain fields? Take soil samples from the main areas to look for fertility differences. It may be that strategically applied manure or lime can make the difference.
Carry field maps in field equipment: Identify and record problem areas such as weed infestations, track loads harvested, and record manure spreading activities such as loads applied and where to start spreading the next time if the field was not completed.
To avoid creating or enhancing fertility differences in the first place, spread manure evenly across a whole field, especially the parts farthest from the driveway.
If your corn planter allows, pre-plan adjustments to seed populations based on grain or silage, particular hybrid population response, fertility and drought potential.
If your planter allows, pick two or three fertilizer rates to match general fertility conditions of individual fields.
Evaluate mixed hay stands in the spring for relative “grassiness,” especially after this past growing season. Rank fields and/or farms and generally harvest from highest to lowest grass content.

You are already practicing site-specific agriculture on your farm. It’s nothing new – just increasingly important for profitability.

FYI
Jason Kahabka is an Extension Support Specialist for the Precision Agriculture Program of the Department of Crop and Soil Sciences at Cornell University.

Karl Czymmek is a senior Extension associate in field crops and nutrient management with the PRO-DAIRY program.