Impacts of fertigation via sprinkler irrigation on nitrate leaching and corn yield in an acid–sulphate soil in Thailand

A study was conducted in an acid–sulphate soil in the central region of Thailand, in 1999, and 2000 to assess the influence of different rates of N fertigation on corn (Zea mays L.) yield and nitrate leaching. Nitrogen source was urea and there were four N fertigation treatments which include 0 (control), 100, 150 and 200 kg N ha−1, each having three replications arranged in a randomized complete block design (RCBD). Soil was irrigated to field capacity at 50% available soil moisture depletion regime throughout the season. Leaching losses were calculated from measured daily fluxes of water percolation, soil water NO3–N concentrations extracted by soil water sampler and from a seasonal N mass balance. The average maximum corn grain yield of 3.52 t ha−1 was obtained at 200 kg N ha−1 in 1999 and 5.42 t ha−1 was obtained at 150 kg N ha−1 in 2000. But the statistical analysis did not show any significant differences in grain yield between N200 and N150 treatments in either year. The leaching measurements showed that the highest values were obtained in N200 treatments in both years with 23 and 5.3 kg N ha−1 in 1999 and 2000, respectively. The lowest yield of 0.55 and 0.98 t ha−1 were obtained at 0 kg N ha−1 in 1999 and 2000, respectively. Also the results showed that a fertigation system can be an efficient practice and an advanced way to give water and plant nutrients together to the crop.