Soil salinity in irrigated fields used for urban agriculture under a semi-arid environment of South Africa

Urban Farm DB summary

A study of soil salinity in irrigated fields used for urban agriculture in a semi-arid region of South Africa. It compares sodium levels (19.3 vs. 9.8), pH (7.13 vs. 6.3) and electrical conductivity ECe (22.1 vs. 7.9 dS/m) between topsoil and subsoil layers, finding that calcium, magnesium and potassium (unlike sodium) were higher in the top than the subsoil layer, while pH and ECe did not differ significantly by depth overall. By irrigation method, basin irrigation produced the highest accumulation of calcium, magnesium, potassium and sodium, followed by drip and then sprinkler irrigation, with the same ranking (basin > drip > sprinkler > control) for pH and ECe; sprinkler irrigation was the only method showing higher pH and ECe at 10-20 cm depth than at 0-10 cm. The study concludes that irrigation is increasing soil salinity and points to the need for sound irrigation water management, particularly appropriate irrigation scheduling.