Author(s): P. Cepuder; W. Loiskandl
Linked Author(s):
Keywords: Groundwater pollution; Nitrogen; Leaching; 15 N measurements
Abstract: Ground water pollution due to agricultural land use is a serious problem in many agricultural regions. To estimate the efficiency of fertilizer application investigations were performed at the experimental farm of the University of agricultural sciences Vienna in Gross-Enzersdorf. On a research field divided into micro plots measurements of nitrogen leaching with four different amounts of fertilizer applications were made. In order to find out the fertilizer uptake by plant, the amounts of fertilizer retained and leached through soil profile, labeled 15 N-fertilizer with 2. 5% atom excess was applied on each micro plot. The nitrate concentrations below the root zone were measured for winter wheat followed by cover crop using suction cups. Soil water content was measured in soil profile with neutron probe and soil water tension was measured with tensiometers. The yield of crops together with total nitrogen in grain and straw from fertilizer and soil were calculated. In the paper estimates of mineralization, immobilization and actual fertilizer used by the crops are given. It was observed that on an average winter wheat took between 27% and 44% of the applied fertilizer. The storage of nitrogen from fertilizer in soil ranged between 22% and 36% and only a small part of the applied fertilizer was leached until the end of the investigation period. The high nitrate concentrations measured in percolation water were a result of previous fertilizer applications, tillage operations, crop rotation and of climatic conditions.
Year: 1999