Nitrogen Leaching From Controlled Release Liquid Fertilizers Applied to Three Soils.

New liquid fertilizers have been formulated to slowly release nitrogen. However little information is known about their nitrogen release when applied to different soils. In two, 56 day greenhouse experiments, mineral nitrogen and total Kjeldahl nitrogen (TKN) leaching curves were determined by applying either no fertilizer, urea, or three controlled release liquid fertilizers to three soils: sand, a mix of 90% sand and 10% peat moss, and a sandy clay loam. All fertilizers leached quickly through the sand soil with no differences in N leached. The least leaching occurred from fertilizers applied to the sandy clay loam. In the second half of EXP2, urea released the greatest TKN when applied to the sandy clay loam, but not when applied to the other two soils. Applying the two controlled release liquid fertilizers with the greatest percentage of urea polymers resulted in less than or similar nitrogen leaching as to when urea was applied.