Effect of marginal water irrigation on soil salinity, sodicity and crop yield

Irrigation with marginal water for an extended period of time will result in potential secondary soil salinization and sodification. The influence of marginal water irrigation on the dynamic balance of soil salinity and sodicity, as well as crop yield under shallow groundwater table, was investigated. This experiment was conducted in a subsurface-drained plot with silt clay soil where forage corn (Zea mays L.) had been planted. The experimental results indicated that the lateral movement of saline and sodic groundwater and its evaporation resulted in a significant difference of salt and sodicity distribution between the north and south parts of the experimental plot. Under the experimental conditions, the salt in 0～1.2 m soil increased by an average of 7.5% and sodicity by 19.6% during the corn growth season. Plant yield and height inversely correlated with soil salinity. Among grain yield, dry matter weight and plant height, the grain yield was most negatively affected by soil salinity. Therefore, utilizing rainfall in winter to leach soil salt is necessary to maintain sustainable irrigation agriculture in this region.