Document Type : Research Article
Authors
1 University of Tehran
2 Karaj
Abstract
Abstract
In this study, distribution uniformity of fertigation in different furrow irrigation regimes was evaluated. The experiments included injection of fertilizer during only the first half of the irrigation event (FH), injection in the second half (SH) and injection during the entire irrigation (T) event. These options were conducted under free draining and blocked-end conditions with cutback method. The experiments were carried out in Golmakan Agricultural Research Station in 2006. Potassium nitrate was used in the experiments. Distribution uniformity of low half (DULH) and low quarter (DULQ) of water and fertilizer was calculated to evaluate different fertigation scenarios. The results showed that there is no significant difference among the distribution uniformities in the three application times (FH, SH, T). No significant difference was observed between distribution uniformity of free-draining and blocked-end experiments. The best case in blocked-end conditions was injection during the entire irrigation event preferably starting before completing advance phase. Because in this case, solute losses due to runoff from the outlet is zero and also distribution uniformity is somewhat higher whereas in free-draining conditions, fertilizer application during the first half of irrigation provides acceptable fertilizer uniformity and least losses due to runoff. The results also showed that fertilizer losses due to deep percolation in this method of fertilizer application (fertigation) would not be a threat in case of selecting proper irrigation parameters.
Key words: Furrow irrigation, Fertigation, Distribution uniformity, Mathematical model
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