Comparative yield and water use efficiency of two maize hybrids differing in maturity under solid set sprinkler and two different lateral spacing drip irrigation systems in León, Spain

The purpose of this study was to determine the technical viability of drip irrigation of maize in León, Spain, establishing the optimal parameters for crop cycle length and spacing between laterals and the feasibility of mild deficit irrigation. Water use efficiency (WUE) and irrigation water use efficiency (IWUE) were also determined, compared to the sprinkler method of irrigation widely used in the region. Treatments consisted of two irrigation methods (IMS: sprinkler irrigation, and IMD: drip irrigation) and two hybrid maturities (HMSS: short season, and HMMS: medium season). In sprinkler irrigation method, the irrigation level was 1.00 ETc (crop evapotranspiration). Only for the drip irrigation treatments, subtreatments consisting of two lateral spacings (LS2: two rows, 110 cm, and LS3: three rows, 165 cm) and two irrigation levels (IL80: 0.80 ETc and IL100: 1.00 ETc) were studied. The mean grain yield was 17,551 kg ha−1 at 14% moisture content, with no significant difference between irrigation methods. The yields obtained with the medium season hybrid were significantly higher (18,191 kg ha−1) than those obtained with the short season hybrid (16,910 kg ha−1). No statistically significant differences were found between the yields obtained with the IL80 and IL100 treatments. Yields were slightly higher with the LS2 treatment than with LS3, although the level of statistical significance was very low (P = 0.083). The mean WUE was 3.28 kg m−3, and no significant differences were found between irrigation methods or crop cycle length. Highly significant differences were obtained between irrigation methods for IWUE: 3.38 kg m−3 with IMS compared to 4.67 kg m−3 with IMD, and reaching 5.17 kg m−3 for IL80. The main conclusions of this study are that drip irrigation of maize is technically viable in the region and mild deficit irrigation does not reduce yields, obtaining yields equal to those achieved by sprinkler irrigation whilst presenting much higher irrigation water use efficiency.