Evaluation of silage maize production under pulsed drip irrigation in a semi-arid region

Using pulsed management in drip irrigation systems has become popular as a technique that improves soil water distribution patterns and increases water productivity (WP). Pulsed irrigation consists of on-off cycles, which continue until applying the entire irrigation depth. A two-growing season field experiment was conducted to examine the combined effects of pulsed drip irrigation and its off-time duration on the silage maize yield and WP in Varamin, Iran using a randomized complete block with a split-plot design and three replications. The pulsed management included four levels, applying the irrigation volume in one, two, three, and four pulses (P1, P2, P3, and P4) and off-time duration consisting of one and three, times the on-time duration in a pulse (T1, T3). The results indicated that the interaction of the various treatments on the yield, yield components, and WP of the silage maize was significant (P < 0.01). Increasing off-time duration from T1 to T3 resulted in a 6.5% increase in plant height and stem diameter, a 13.9% increase in 1000-grain weight, and an 11.6% average increase in crop yield and WP over two growing seasons in P4 treatment. Investigating soil water content in the crop root zone demonstrated that increasing the number of pulses and off-time duration and, thus, increasing the time for the infiltration process and soil moisture redistribution improved water distribution in the soil profile, crop yield, and WP. Therefore, with similar soil texture and a high discharge rate of emitters, it is recommended to increase the number of pulses and off-time duration to enhance water redistribution in the soil.