by Dr. Jon Chernicky, Agronomy Field Technical Support
Arizona produces the highest yield of alfalfa hay per acre than anywhere in the United States. Yields from 8 to 18 tons per acre are possible with proper management. Arizona’s average is around 8 tons per acre over 8-10 cuttings. There are over 250,000 acres of alfalfa grown in Arizona. With that amount of nutrient tonnage, the soils must provide the crop with approximately 450 lbs of nitrogen, 98 lbs of phosphorus, and 256 lbs of potassium. For the past 40 years, growers have tried to satisfy the thirst for these macronutrients through applications of synthetic fertilizers like Mono Ammonium Phosphate (MAP) or 11-52-00 and Ammonium Poly Phosphate or 10-34-00. The trouble is with such a program in the high pH calcareous soils of the Desert west, that levels needed to maintain a stand of alfalfa for a period of 3 years simply isn’t there economically when relying on chemical fertilizers alone. In 2021, the cost of 11-52-0 is almost $900 per ton and 10-34-0 is has been hovering around $750 per ton which has more than doubled since 2019 with no relief in sight.
The Numbers are Deceiving
The current program in alfalfa generally involves two applications of 11-52-0 at 200 lbs per acre applied during the spring and fall to maintain the stand health. The cost of this program in 2021 is around $180 per acre per year. The question a grower must ask is can these two applications satisfy the needs of the crop and the answer is a resounding NO. If we apply 400 lbs of 11-52-0 we are only getting 44 lbs of nitrogen, 208 lbs of phosphorus, and no potassium. If you look at the consumption numbers above it appears that we are applying more than enough phosphorus to supply the needs of the crop but in this case, the numbers are deceiving. Of the 208 lbs that are applied to the crop, in high pH soils that are high in calcium and bicarbonates, 95% of the phosphorus reacts with the free calcium that is present in the water and soils to make it unavailable to the plant which means that only 10.4 lbs of phosphorus is plant available. If you are a grower this once relatively inexpensive source of phosphorus has become very expensive given the efficiency at which it is delivered to the plant. What is then the real cost of this program per lb of phosphate delivered to the soil and later taken up by the plant? The answer is simple. If we just look at the 208 lbs per acre that is applied twice during the season we can say that we are paying $4.32 a pound, however, remember that only about 5% of that 208 lbs per acre is available! In this instance, the cost rises dramatically to $86.50 per lb.
Questions: Where did all the phosphorus go that I applied? Can I get it back?
The answer is yes but are you willing to change your fertility program and bring biology into your program. At a pH of 8.2 and you can acidify your soil by applying an acid to release the Calcium from the phosphorus and make both of them more available. However, this is a temporary solution since there is so much free calcium in Arizona soils. This is where biology can come to the rescue.
QLF Agronomy’s Liquid Carbon Based Fertilizer, “L-CBF BOOST HP”, has an analysis of a 4N-8P-3K-2S. Research that has been conducted over the past three years in Arizona alfalfa fields has demonstrated that this product is more effective at maintaining a stand of alfalfa than 400 lbs of MAP 11-52-0. That has growers scratching their heads saying how can this liquid applied three to four times at 5 gallons per acre over the course of an entire year be more effective than applying 200 lbs of phosphate applied twice, spring and fall. The answer is simple! Working with Biology and partnering with better Chemistry = more plant health and performance; whereas chemistry alone creates chronic plant stress.
The L-CBF BOOST HP program in Arizona alfalfa is very effective. We are creating a stand of alfalfa that can maintain itself if given the proper environment. The QLF Agronomy’s BOOST HP fertilizer package helps create and maintain that proper environment. We are meeting the needs of the plant at establishment and through the life of the stand by feeding the plant as well as the soil through the addition of various forms of available carbon (energy from sugar cane molasses), and a balanced plant diet of high-quality fertilizers (macro and micronutrients). With a steady supply of plant-available nutrients through inorganic and organic sources in the soil, we can maintain a higher rate of photosynthesis in the field. This performance improvement maintains healthy top growth as well as healthy root growth. The nutrient cycling is an enhancement from our “Liquid Carbon Based” program that clearly increases biological activity in the rhizosphere and successively produces more organic acids around the root zone causing a change in pH at the soil root interface which feeds and fosters a beneficial relationship with microorganisms. One example of this improvement in biological activity can be observed by the presence of active nodulation. A healthier alfalfa plant with lower root zone pH can better feed rhizobia bacteria that produce nitrogen-fixing nodules. A high protein crop such as alfalfa has a high nitrogen need and demand. Fostering this relationship with beneficial bacteria can satisfy all the alfalfa’s Nitrogen requirements. Simply put Alfalfa plants supplemented with our L-CBF BOOST HP program can mineralize our desert soils and unlock the phosphorus that has been fixed in the soil for decades. It sounds complex but it’s really describing nature at its best (Chernicky, 2021). Chernicky (2021) reported the cost of this program is competitive and is better than synthetic fertilizer alone.
Chernicky (2021) stated that agriculture for over 40 years has relied on synthetic fertilizers alone to produce crops in the United States and has thrown away the whole concept of carbon cycling. Arizona soils are low in organic matter (<1%, have become salted out from extensive use of salt-laden fertilizers which reduce crop productivity in the long run. Extensive leaching with good quality water is no longer an option since most of our aquifers are compromised and there are serious shortages on the Colorado River.
Contact your local QLF Agronomy representative to learn more about how we can bring biology and better nutrient utilization efficiency back into your Alfalfa fertility program.
Chernicky, J. (2021). Arizona Alfalfa Production Takes Carbon Based Approach [unpublished manuscript]. QLF Agronomy. Technical Representative