A lysimeter study under field conditions of nitrogen and phosphorus leaching in a turf grass crop amended with peat and hydrogel

Golf courses represent an agricultural activity wherein grass is intensively cultivated using large quantities of fertilizers. In the present study, nitrogen and phosphorus leaching was analyzed over two years in an experimental green under actual field conditions. The green contained four plots with distinct amendments (P1: hydrogel + peat, P2: peat, P3: hydrogel, and P4: no amendment). The applied doses of nitrogen ranged from 5 to 103 kg/ha and of phosphorus from 9 to 31 kg/ha. The irrigation level varied as a function of the rainfall regime and the water requirements of grass; overall water intake varied from 1550 to 2080 mm/year. Daily, leached water volume was calculated, and samples were taken for chemical analysis. Nitrogen and phosphorus mass balances were calculated for different periods based on the collected data. The plot amended with peat and hydrogel (P1) had reduced water flow: the percentage of drainage water varied from 8.4 to 29%. As a result, the dissolution and leaching of nitrogen (N) and phosphorus (P) were the lowest in comparison to the other plots. According to the calculated mass balances, the lowest leaching values were also recorded in this plot (P1), ranging from 0.5 to 6.3% for N and from 0.8 to 20.9% for P. The plot without amendment (P4) drained the most water (25.9-44.8%) and leached the highest quantities of N and P. ranging from 9.1-45.7%, and 6-35.9%, respectively. The use of double amendments (hydrogel and peat) therefore represented optimal operating conditions for the green. Moreover, a relationship was found between increasing rates of fertilization and increasing percentages of N and P leaching as well as between higher irrigation levels and greater leaching. (C) 2018 Elsevier B.V. All rights reserved.