Many producers are being offered non-traditional nutrient sources or application systems. Some of these approaches are based on questionable science or highly inflated claims of effectiveness.""
----------------------------------------------------------- Rising cost of fertilizer brings new claims from alternatives By Dr. Tony Provin and Dr. Larry Redmon Apr 30, 2008
During the past three years, the cost of traditional nitrogen (N), phosphorus (P) and potassium (K) fertilizers has increased dramatically. This has left many forage producers looking for alternatives to traditional inorganic fertilizer.
Basically, the only alternatives include manures such as broiler litter (N-P-K), biosolids (waste water treatment sludge, N-P), and the use of forage legumes (N). Producers most impacted by high fertilizer prices are those who own property with a poor history of appropriate soil fertility and hay producers.
Many producers are being offered non-traditional nutrient sources or application systems. Some of these approaches are based on questionable science or highly inflated claims of effectiveness.
Planning
The first step an agricultural producer should take prior to fertilizer application is to evaluate their property for production potential. The evaluation should include determining the yield potential of the acreage, obtaining soil samples and an analysis of each unique area of each field.
Based on this evaluation the best use for each parcel of land should be determined. Dr. Tony Provin, director of the Texas AgriLife Extension Service Soil, Water and Forage Testing Laboratory, strongly recommends collecting 10-15 individual soil cores for each individual area of land that should be managed and fertilized separately.
Provin also encourages producers to sample hay fields on a 10-acre basis, while grazing pastures should be sampled on a basis of not more than 40 acres per composited sample. Instructions for proper field sampling can be found at http://soiltesting.tamu.edu.
The physical process of collecting soil samples can provide important additional information to the producer. Provin stated that when obtaining soil samples, producers are encouraged to map their fields with regard to weed pressure, percentage of cover, and level and depth of shallow compaction, if any compaction is present. Failure to address these additional issues may reduce the overall economic response to fertilization.
Once producers have obtained soil test recommendations and have developed field maps of their acreage, they should then consider both short-term and long-term management plans.
Regarding some short-term management options, Dr. Larry Redmon, Texas AgriLife Extension Service State Forage Specialist has been a strong proponent of reducing hay acreage to only the highest yielding areas, maximizing hay yields through good nutrient and harvest management, while using other less productive acreage as grazing areas.
The price to produce well-fertilized hay this year will likely approach $125 per ton. Many producers, especially smaller producers, generally cannot justify the cost of purchasing and maintaining hay harvesting equipment.
Couple this aspect with the cost for soil fertility associated with hay production and most producers will be better served simply purchasing their hay from reputable hay producers. Another cost savings approach that may be accomplished in the short term involves the construction of a round bale hay storage barn.
Hay, even in tight round bales, loses dry matter and nutritive value rapidly when exposed to rainfall and poor storage conditions. Given the high prices of today’s hay, Redmon has noted that hay barns often pay for themselves in just a few years simply by decreasing dry matter loss and forage nutritive value.
Properly stored hay has been known to maintain its nutritive value for longer than 20 years. If a barn is not utilized, hay tarps can help minimize hay loss during storage.
Longer-term Management
Fertilizer prices are unlikely to drop in the future. Some producers are looking toward the use of manures and biosolids to provide their soil nutrient requirements. While manures and biosolids, where available, can provide nutrients at a substantial cost savings, producers need to realize that P typically will begin to accumulate where these materials are used.
Careful monitoring of the soil test P is necessary to ensure that the level does not build up beyond the accepted threshold of 200 ppm. Biosolids of interest should be those classified as Class A. These biosolids do not pose risks associated with heavy metals or pathogens.
Provin recommends the application of manures and biosolids in late winter or very early spring, as there is some lag time in the breakdown of the organic compounds before the nutrients can be taken up by plants.
The use of forage legumes, which fix atmospheric N in their root systems, in grazing systems should be considered by all livestock producers. Provin suggested planning for legume establishment six to 12 months prior to the actual seeding of the legumes. Soil testing and correction of pH and nutrient deficiencies are critical in the establishment of legumes. Most legumes require a higher pH and a higher level of available P.
Additionally, carryover of broadleaf herbicides containing picloram or metsulfuron may inhibit germination of legume seedlings and should not be used the year of legume establishment. Most forage legumes are cool-season clovers and medics. These are often planted in mid-fall, germinate and make most of their growth in early spring in a fashion similar to ryegrass.
Redmon cautions producers that any cool-season annual, legumes included, can inhibit warm-season grass production in the spring and should be removed via grazing in a timely manner. While more money has probably been lost due to fear of bloat than actual bloat death loss, Redmon advises producers to be aware of the potential for bloat and understand the management implications necessary to reduce the incidence of bloat issues.
While the legumes provide high value late winter and early spring forage grazing, the fixation of N by Rhizobium bacteria associated with legume roots has been the major reason producers have adopted legume systems. The amount of N fixed and made available to the warm-season grass via nutrient recycling is dependent on the biomass production of the legume.
This amount varies by soil, soil fertility and legume species and ranges from 25-100 lbs of N per acre per year. At the Texas AgriLife Research and Extension Center at Overton, some bermudagrass pastures have not received N fertilizer for over 24 years. Clover has been established each fall in the pastures and has provided the N requirement for the warm-season grass during the summer months, albeit at a slightly reduced stocking rate.
Fertilizer sources and application methods
Redmon has received numerous questions from producers about reducing fertilizer application rates. In some cases, producers who have practiced good nutrient management maybe able to reduce P and K applications for one or two years of hay harvests. In the long-term, however, failure to replace nutrients removed during hay harvests will significantly reduced yields and will result in decline of introduced forage stands.
As a rule of thumb, each ton of forage removed in hay harvests will remove 14 lbs of P2O5 and 48 or more lbs of K2O per acre. Nitrogen requirements to produce 12 percent crude protein hay are generally considered to be 50 lbs of N per ton.
Redmon noted that typically, forage stand loss problems have been traced back to low soil pH and very low available soil P and K levels. In these cases, producers often failed to soil test their hay fields until these nutrients had been mined to low levels. The result was a significant stand decline, loss of production, and increased weed infestation.
Redmon also cautioned producers to the claims of some fertilizer dealers about the use of foliar fertilizers. While the fertilizer grade liquid formulations percent N, P2O5 and K2O, may be guaranteed, claims of super plant uptake efficiency of these nutrients is not backed up by research. In fact, most research suggests the opposite is true. Some claims of the use of foliar fertilizers also come with statements about reduced costs. This is usually obtained by using reduced amounts of actual N, P2O5, and K2O applied.
Producers should also be warned against attempting to apply foliar fertilizers themselves. Usually there are problems with delivery rates and potential corrosion of the pump.
Producers should be aware regardless of form of fertilizer used, the correct amount of nutrients must still be required to achieve the desired yield. As they say, there is no such thing as a free lunch.
