NITRATE AND AMMONIA LEACHING OF BERMUDAGRASS TURF ON DIFFERENT SUBSTRATES IN MEDITERRANEAN AREA (CENTRAL ITALY)
Turfgrass culture on substrates with high permeability can result in leaching from fertilizers and pesticides. We measured the effects of five different substrates on the amount of percolating water and nitrate and ammonia leaching in a bermudagrass (Cynodon dactylon) turf. The substrates were: (SS) silica sand and peat; (SSZ) silica sand added with zeolite; (TPS) native soil protected by a top layer of 5 cm of silica sand or (TPC) calcareous sand; (T) native soil. We also tested the effect on turf growth of two root zone depths, 0.2 m and 0.4 m. Percolates were measured daily by cylindrical lysimeters (0.9 m Ø). In each substrate block there were two lysimeters 0.4 m deep and two 0.2 m deep in order to test for substrate depth effect on leaching. Watering and nitrate fertilization were the same in all treatments (15 g N m-2y-1 in three doses). The results showed that winter leaching was strictly related to rain amount. During summer (with irrigation) leaching volumes were greater in 0.4 m deep lysimeters. Daily leaching of N-nitrate and N-ammonia was affected by substrates and sampling time. The yearly highest N-nitrate concentration in leaching was originated from substrates containing native soil (TPS, TPC, T) after the first, late spring, fertilization. In July and August, when plants reached their fastest growth, with leaching volumes ranging from 35 to 50% of the irrigation, N-nitrate concentrations were lower than 1 mg L-1 without differences among substrates. The leaching of N-ammonia was highest by the end of August, during maximum turf growth, but concentration was lower than 2 mg L-1. The trend of N-nitrate leaching was characterized by peaks and drops, while by a small, continuous flow in N-ammonia leaching. Further research is needed to assess the nature of N-ammonia leaching.
Cereti, C.F., Rossini, F. and Stancanelli, G. (2008). NITRATE AND AMMONIA LEACHING OF BERMUDAGRASS TURF ON DIFFERENT SUBSTRATES IN MEDITERRANEAN AREA (CENTRAL ITALY). Acta Hortic. 779, 669-676
sand, ion selective electrode, Cynodon dactylon turfgrass