ABSTRACT
The study was conducted during the dry season in 2016 at the Irrigation Research farm of Institute for Agricultural Research, Samaru, Zaria, to determine the effect of deficit irrigation and mulch on yield and water use of Cucumber crop. The experiment consisted of four levels of moisture depletion at 0%, 25%, 50%, and 75% (I100, I75, I50, and I25) of irrigation water application depths and three mulch types Rice straw mulch; Black polythene mulch, and No mulch (RSM, BPM, and NM) respectively. This was replicated three times laid in a split plot design (SPD). The irrigation water was allocated to the main plot, while mulch material was assign at the sub-plots. Water was applied to the basin using a PVC pipe of 7.5 cm diameter and 50 cm length to serve as an orifice. The soil moisture was measured and monitored during the growing season of the crop, through an access tubes installed in each basin at three different depths of 0 - 15, 15 - 30, 30 - 45 cm coupled with theta probe moisture instrument. The result showed that application of 25% water deficit (I75), combined with rice straw mulch gives the highest yield of 14.60 t/ha when compared to irrigation at 25% water deficit (I75) with Black polythene, and No Mulch with the same irrigation level. The yield obtained from the treatments ranges from 4.33 t/ha to 14.60 t/ha. The least yield was obtained from the treatment (I25NM), while the highest yield was obtained from the treatment (I75RSM). The highest crop water use efficiency (CWUE) and irrigation water use efficiency were 93.7 kg/ha/mm and 90.3 kg/ha/mm at 0% level of moisture depletion, respectively, while the least is at 25% moisture depletion with value of 65.3 kg/ha/mm and 65.5 kg/ha/mm, respectively. The yield response factor (Ky) for the total growing season obtained for RSM was 1.013; for BPM was 1.243 and for NM was 0.549, respectively. The study showed that crop water use (CWU) of the Cucumber crop decreased with increase in irrigation deficit. The Kc values ranges from 0.34 - 0.48 for initial stage, 0.43 - 0.66 for development stage, 0.30 - 0.85 for mid-season stage, and 0.30 - 0.69 for late season stage. From the results obtained it shows that applying management methods such as the use of mulch cover for better use of water resources and in order to minimize water stress appears to be essential. Also the results showed that the interaction effects of irrigation and mulch treatments were significant on yield, length, weight and number of fruits.