Effects of irrigation frequencies on soil salinity and crop water productivity of fodder maize

This study was carried out at the experimental station of Department of Irrigation and Drainage, Sindh Agriculture University, Tandojam to investigate the effect of different irrigation frequencies on soil salinity and crop productivity. Four irrigation frequencies i.e. Irrigation after 7 days (T1), Irrigation after 14 days (T2), Irrigation after 21 days (T3), and Irrigation after 28 days (T4) were applied to fodder maize. The results showed significant effect of treatments on soil salinity. The EC of soil slightly increased under all treatments for all depths as compared to pre-treatments. At treatment T1, the salt amount was most noticeable and the highest EC (1.85) was observed at top surface of soil while the lowest (1.65) EC was observed under T4 at the comparable depth however, EC decreased at deeper depths under all treatments. The pH, SAR and ESP of soil decreased at all treatments however this decrease was more pronounced under T1 as compared to other treatments. The highest SAR was observed under T4 (9.40) while the lowest (8.00) under T1 for the matching depths. Similarly, the highest ESP was observed under T4 (11.40) while the lowest (10.15) under T1 for the similar depths. The results on the analysis of variance were non-significant between soil salinity parameters observed for pre-experiment. However, the results of analysis of variance on pH, EC, SAR and ESP showed significant differences between treatments in the post experiment. The maximum plant height, stem girth, number of leaves per plant and fodder yield were observed when the maize fodder was irrigated with a 7 day frequency and it was followed by other irrigation frequencies. Similarly, crop water productivity was 4.5, 4.2, 3.9 and 3.0 kg m⁻³ under T1, T2, T3, and T4 treatments, respectively. These results revealed that T1 produced the maximum crop water productivity as compared to rest of the treatments. The farming community is thus recommended to apply irrigation, to maize fodder crop, with 7 day frequency in order to get maximum fodder yield.