Tools Apply Inputs With Precision

By Barb Baylor Anderson
Progressive Farmer Contributing Editor

Rain makes grain, but sometimes Mother Nature needs a little help. That help arrived with the introduction of commercial fertilizer and irrigation to modern crop production. Today, environmental and economic pressures are transforming how growers use nutrients and water to boost crop yields. In the process, farmers are turning to technology that can support their efforts.

"Research shows up to 60% of yield [for all crops] is dependent on fertility," says Kyle Freeman, Mosaic director of new product development.

Replenish the soil. He says as American farmers push corn yields ever upward, the higher yields create "a burden on the soil as more nutrients are removed. Products are available to address that need, and more research is under way to better understand that burden."

For farmers, that burden includes applying fertilizer with greater precision. They are incorporating diagnostic tests, ranging from computer programs to plant tissue testing, and nutrient sensors to hone in on specific nutrient needs.

George Brand, Waterloo, Ind., manages a 400-cow dairy with his wife, Christine, and son, David. Together, they produce 2,500 acres of corn and soybeans.

At any given time, the dairy has some 900 head, which generates a lot of manure that Brand incorporates into the family's crop-production plans. He soil-tests annually to see what nutrients will be needed for optimum corn production. He also analyzes solid manure and liquid manure from their lagoons. He uses the test results to write a nutrient prescription to variable rate-apply manure on fields in the spring. Rates vary by soil type and fertilizer recommendations. Brand usually applies 2 to 3 tons per acre of dry manure and 4,000 to 5,000 gallons of liquid manure per acre. Manure comprises up to 80% of his total fertilizer use.

During the season, Brand has an agronomist tissue-sample corn leaves so he can variable rate--apply 28% UAN, typically sidedressing 10 to 50 gallons per acre. The tests provide an analysis of how nitrogen (N) is being used by the corn and are the basis for adjustments to N rates. With the system, Brand sees better N utilization. Plus, less is left in the soil that can be lost to the environment. Best of all, the family saves money.

"We see $25- to $100-per-acre savings with variable-rate applications," he says. "For us, it is all about cost savings and environmental impact. Our farm is on rolling land. We are in the St. Joseph River Watershed, which goes into Lake Erie, so we focus on protecting groundwater."

PINPOINT EFFICIENCY

Peter Scharf, University of Missouri Extension nutrient management specialist, says N use has become more efficient. U.S. farmers now apply about 1 pound of N per bushel of corn produced, down from a peak of 1.3 pounds of N in the late 1970s. At the same time, corn yields have risen from an average of 70 bushels per acre in 1970 to about 160 bushels today.

Bob and Monte Bottens, Cambridge, Ill., use a year-round fertility program that includes periodically pinpointing specific nutrient needs for 1,850 acres of no-till corn and soybeans. Monte also is a crop consultant.

"We apply nutrients only at time of need with what is needed. We do not fall-apply," he says. "We take an integrated approach with in-row starter and banded nitrogen at planting followed by sidedress applications."

The father/son duo start their nutrient decision-making process based on soil tests and soil type. They have created management zones in fields using yield data from the past 10 to 12 years.

Seed is planted by management zone with in-row fertilizer, including phosphorus (P) and potassium (K) banded at the rate of 5 to 15 pounds per acre, depending on the zone. They also band an average of 75 units of N with sulfur (S) to correlate with yield history.

A late-season sidedress application of N of approximately 75 units per acre (50 to 70% of total N) is applied at stage V8 based on a combination of computer-modeling results and sensor readings. Bottens correlates results from Adapt-N, Climate Pro and the family's customized program with Normalized Difference Vegetative Index (NDVI) readings from GreenSeeker to help determine application timing and amounts.

The GreenSeeker system uses sensors to measure reflected light from the crop canopy to determine how much fertilizer is applied to a particular area of the field.

PRESCRIPTION PROGRAM

While the computer models offer input into N availability at sidedress time, the NDVI readings from the crop allow the Bottens family to fine-tune their N prescription on the go.

"With predictive modeling, you know when to pull the trigger on applications," Monte explains. "We put up to another 75 units of nitrogen based on the plant's needs and weather. We also utilize a planned foliar spray of 3.5 gallons of ANP Traction, Top-End and Draft watered up to 5 gallons." The men make two applications, before and after tasseling, when N demand is high. "We maximize nutrient-use efficiency and return-on-unit produced, and minimize environmental impact. If the timing is right and the nutrients are right, that is all we can do," he says. University research supports Bottens' experience.

In Scharf's university studies, sensors on average saved 14 pounds of N per acre and increased corn yield by 2 bushels. That's based on 55 on-farm demonstrations with side-by-side comparisons between sensor-based rates and producer-chosen rates.

Following harvest, Bottens also calculates a productivity index for fields, weighs that according to the acreages and compares it to the county productivity index. Generally, the family's productivity index is 8% below the county average. The Bottens track the county five-year yield and try to keep their five-year yield 10 to 12% above the county average.

"I prefer best methods over easy, so that is what we do. It takes a lot of work," Monte says. "You have to be comfortable with technology and have a pioneering spirit if you want to do it right."

Mosaic's Freeman expects to see even more fertility options, tools and pressure to use them. "Look at a company like Monsanto that is heavy into seed biotechnology and [you] see they also invest in precision agriculture and other technology that can enhance production," he says. "Farmers will have to step up crop nutrient management as part of their overall plan. Efficiency and environmental impact will be part of our and others' future product-development portfolios."

Bottens sees unique things happening, as well. "Drones may seem like a novelty, but we are creating an agronomic information system that will allow drones to send actionable alerts to farmers. Big data is a big player," he says. "Use of soil microbiology is another area to watch. We are in a modern gold rush in agriculture. Farmers can expect exciting changes for

the future."

WATCH THE WATER

Nearly half of all food produced in the world comes from irrigated land. And while water resources are alarmingly short or even depleted in some parts of the world, experts estimate increasing crop water productivity could feed an additional 110 million people while meeting domestic water demands of nearly 1.4 billion people.

These are part of the findings from a study (www.environment.umn.edu) by the University of Minnesota's Institute on the Environment (IonE) and the Institute of Crop Science and Resource Conservation (INRES), at the University of Bonn, Germany. The study, led by IonE post-doctoral research scholar Kate Brauman, analyzed crop production, water use and crop water productivity by climatic zone for 16 staple food crops that make up 56% of global crop production, 65% of crop water consumption and 68% of all cropland by area.

"Crop production consumes more fresh water than any other human activity, so the study has significant implications for addressing water stress and food insecurity," Brauman says.

"Irrigation makes or breaks farming in a place like the High Plains of Texas," says Justin Crownover, one of the partners involved with Lone Star Family Farms, located in the Texas Panhandle. "Drought here the last three years has limited even more of a limited resource," he says. "The water supply has been recharging less than what we need to take out for crops."

He expects irrigation technology will help drive improvements in crop water management. Sensors, monitors and nozzles can help farmers fine-tune irrigation programs to make every drop count. Center-pivot irrigation and drip irrigation are two ways to provide high-efficiency use and improve yields.

"We've come a long way since gravity and ditch irrigation to save water for the future," adds Jim Aden, Gothenburg, Neb. Aden is part of a family-owned, fifth-generation farm that grows soybeans, alfalfa and no-till food-grade corn for Frito-Lay.

Aden's farm includes hilly and flat terrain, as well as sandy and heavy soils. He used to spend two hours twice a day checking irrigation equipment. To save time, money, fuel and water, he installed a Corner GPS Guidance system on his Valmont pivots. The guidance program uses his existing Real-Time Kinematic system. Computerized irrigation can adjust water and machine speed for field corners and soil types, for example, which he says allows for prescription water applications.

"Base stations provide a centralized irrigation-management system for monitoring and machine control I can check from my smartphone or computer," Aden says. "I know immediately if something is down, or I can turn it off remotely if it rains. I can move pivots from my iPad."

Aden can double corn yields with irrigation, and he saves one-third to one-half the cost using pivot versus gravity irrigation by allowing less water to be pumped more evenly across the field. He applies 12 to 18 inches of water per acre with center pivots during the growing season.

In the future, he hopes to improve environmental benefits and save more fuel by applying fertilizers and herbicides with the water.

"There are GPS-ready panels that can be added on to sense moisture with a probe in the ground that talks to the pivot to adjust it. You also can apply fertilizers and crop inputs," he says. "Variable-rate irrigation is becoming more popular for only putting water where it needs to be. You can put in a prescription and change the rate as the pivot moves."

Crownover also relies on center-pivot strategies, mainly for use on no-till corn, but also on sorghum, canola, triticale, wheat and cotton. He focuses on getting water into the ground.

WATER SAVINGS

"We have not reinvented anything," he says. "Perhaps the biggest thing we have done is made changes with how we use drop hoses."

Crownover has reduced spacings from 60 to 30 inches and slowed down water to get more coverage with the smaller spacings. Drop hoses are 18 to 24 inches from the ground. The greater the distance between the crop and sprinkler, the less efficient because of evaporation and wind drift.

"We use bubblers so we have less fines and mist, and get the water to the ground. We are not wetting all of the foliage. With slower release, we are getting more water on the ground. We can use a quarter-inch to wet the top 6 inches of the soil profile," he says.

No-till residue allows the water to saturate the ground rather than channel and run off, as well.

"I don't know exactly what we save [in water] or gain, but in 2011, our yields were in the low 200-bushel range," he says. "With the new techniques we have implemented, we are back to producing 250-bushel corn."

Crownover adds: "We may try different varieties, hybrids or maturities to reduce water needs, and we may try rotating milo with corn. Our target is to be sustainable producers using less water."

(BAS)

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