Effect of water salinity and irrigation regime on maize (Zea mays L.) cultivated on clay loam soil and irrigated by furrow in Southern Italy

Maize is a crop with high irrigation needs in Italy. In many cultivated areas of the world, the water used for irrigation has a high salinity. To limit the damage caused by the salts provided by irrigation, suitable irrigation strategies can be adopted in relation to the crop, soil characteristics and rainfall regime. Therefore, in order to evaluate the most appropriate irrigation strategy to be used in the cultivation of maize on a clay loam red soil, subject to salinity, a research on a four-year crop rotation was carried out in southern Italy. Maize grain yield and yield characteristics irrigated by furrow with two water salinity levels and five different irrigation regimes, were compared. Grain yield was reduced by 34% in the third crop rotation year when the soil salinity, on average, raised from 3.8 to 7.4 dS m−1. Higher yield occurred restoring 100% of maximum crop evapotranspiration, instead of leaching requirement application which did not affect yield. Soil salinity improved grain protein content and reduced grain moisture content. Rainfall was not sufficient to leach all salts supplied by irrigation. The leaching requirements did not reduce the soil salinity and the harmful effect of salinity on maize yield, because of more salts supplied by higher irrigation volumes.