Michigan State University Extension
Soils & Soil Management - Fertilizer - 06209703
07/10/97
Fluid Fertilizers--Liquids and Suspensions MSU Ag Facts Extension Bulletin E-933, December 1984, Revised, destroy previous editions
by R. E. Lucas and M. L. Vitosh, Department of Crop and Soil Sciences
Fluid fertilizers require special storage tanks, pumps and applicator tanks that can greatly increase costs. Salting out in cold weather can also occur. Adding certain secondary and micronutrients, such as magnesium and manganese, may create a sedimentation problem. Using micronutrient chelates and polyphosphate materials can overcome some of the problems.
Complete N-P-K fluid fertilizers, especially those containing micronutrients, usually contain relatively low amounts of plant nutrients compared with dry fertilizers.
Liquid fertilizers made from orthophosphoric acid have a low capacity to hold micronutrients. However, solutions made from polyphosphoric acid, such as 10-34-0, can hold up to 2 percent zinc, 0.2 percent manganese, 1 percent iron and 1.5 percent copper.