Plant Response to Struvite (NH4MgPO4•6(H2O)) in Appalachia Acid Soil.

Current technology enables to precipitate, remove, and recover phosphorus from animal waste as struvite mineral (NH₄MgPO₄·6(H₂O)). Use of struvite as P fertilizer for growing perennial rye grass (Lolium perenne L.) on Appalachian acid soil (Gilpin soil series) was tested in a pot study. Soil was used as is (pH 4.5) and at two liming rates to reach desired pH (5.5 and 6.5). Struvite and DAP (diammonium phosphate) were applied at three rates to the soil surface or in the seeding furrow. In addition to P, plants were fertilized with Hoagland solution minus P. Control treatment include pots treated with full Hoagland solution with no DAP or struvite addition. Seed germination was recorded 10 days after seeding and aboveground biomass was harvested at day 30 and 60. Root mass was measured at the end of the experiment. Furrow placement resulted in higher plant growth compared to surface application for both fertilizers. This effect was more pronounced in initial growth during the first 30 days. Struvite application resulted in higher germination and root and aboveground biomass at the non-limed soil and at the low liming rate. At high lime application rate plant response to struvite was not significantly different from that of DAP. The results of this study suggest that struvite can be placed at the seed furrow without inhibiting seed germination, allowing more intimate placement of the fertilizer. This is likely to result in higher P use efficiency and to minimize P losses in surface runoff due to surface application of P fertilizers.