Effect of deficit irrigation and nitrogen fertilizer source on earyield, nitrogen use efficiency and water productivity in sweet corn (Zea mays L. cv. Saccharata)

This experiment was carried out to investigate the effect of biopolymer coated urea under deficit irrigation on ear yield, nitrogen uptake, nitrogen recovery efficiency and nitrogen use efficiency, grain protein and plant nitrogen content in sweet corn (KSc 403). The experiment was carried out in strip plot arrangement based on randomized complete block design with four replications in Agricultural Sciences and Natural Resources University of Khuzestan, Iran in 2015. The experimental treatments included; three levels of irrigation (100%, 80%, and 60% of plant water requirement) assigned to vertical plots and six levels of urea fertilizer (uncoated urea, sulfur-coated urea, starch-coated urea, agar-coated urea, and chitin-coated urea) randomized in horizontal plots. The results revealed that coated urea fertilizer with chitin could increase ear yield and NUE by of 20.2% and 32.9%, respectively, in comparison with uncoated urea fertilizer. The highest water productivity and economic water productivity was obtained from chitin coated urea and highest native soil nitrogen from non-coated urea fertilizer. The highest N uptakes and recovery efficiency were obtained in chitin-coated urea fertilizer and 100% of water requirement treatments. However, no significant difference was observed between this treatment and agar coated urea in 100% of water requirement. Redudcing 40% in water requirement decreased ear yield and NUE by 40.3% and 41.1%, respectively. The highest ear yield of sweet corn were obtained from 100% of water requirement (10238 kg.ha-1) and chitin coated urea fertilizer (9853 kg.ha-1) that was not significantly different with other biopolymer coated urea treatments. In conclusion, the results of this experiment showed urea coated fertilizer with biopolymers increased ear yield and nitrogen uptake in sweet corn and enhanced agronomic nitrogen use efficiency, nitrogen recovery and water productivity.