Optimizing surface fertigation practices for application in farmers’ field in the North China Plain

Applying nitrogen fertilizer is commonly used to increase yields of surface-irrigated crops, despite often low application efficiency (AE) and distribution uniformity (DU). Surface fertigation, the application of fertiliser dissolved in irrigation water, is a promising technique for improved on-farm performance. This study evaluated surface fertigation strategies in a field experiment and by modelling with WinSRFR. The field experiment was conducted in the North China Plain in 2017–2019. The aim was to test different practices and for model validation, then to develop optimisation scenarios. The study found, first, that conventional practices resulted in low AE of irrigation, around 40 % in wheat season and 60 % in maize season. DU, however, was satisfactory in both wheat and maize seasons, averaging 80 %. Second, surge border irrigation showed no significant advantage in terms of performance compared to the conventional practice of continuous border irrigation. Third, the WinSRFR model offered satisfactory accuracy compared to field-measured data; and soil infiltration parameters, such as the Kostiakov K, showed temporal variation during the crop seasons. Fourth, improved fertigation scenarios were developed by optimising the cut-off ratio in tandem with changes in border length and fertigation timing. The optimised strategies resulted in AE and DU increasing to some 90 %. •Fertigation performed better than fertiliser broadcasting practice in terms of distribution uniformity.•Surge border fertigation showed no significant advantage compared to continuous border fertigation.•It is essential to consider temporal infiltration variation when modelling irrigation management practices.