The agronomic effectiveness of phosphorus fertilizers was reviewed by Engelstad and Terman (91)
Most crops require readily available phosphorus, and most soluble sources perform similarly. However,
in some situations the ammonium phosphates produce phytotoxicity (92)
, and their use is often discouraged
when high amounts of phosphorus are required. For example, for economic reasons, diammonium
phosphate typically is broadcast applied for lettuce production in the southwestern desert, but its use is
discouraged when broadcast rates are high or when phosphorus fertilizer is banded near the plants.
Soluble, dry fertilizers and solution fertilizers perform similarly under many production systems.
However, there are some unique production situations where solution sources may present
logistical advantages. Often solution sources are easier to use in band placement or point-injection
technologies. Generally, solution sources would be utilized in application with irrigation water.