Rehabilitation of a saline soil with gypsum in a pecan orchard in the Yaqui Valley

Abstract

Pecans are cultivated extensively in the Yaqui Valley, Sonora. These soils often have problems of salinity and high concentrations of exchangeable sodium, which cause a decline in pecan productivity. At the end of the season of irrigation with water from the system of reservoirs on the Yaqui River, groundwater is generally used from May to August. This can result in salt accumulation in the soil when water is of poor quality. Gypsum has been used as an amendment to rehabilitate soil by improving its physical and chemical properties. The main objective of this study was to investigate the effect of gypsum application to a saline soil of a pecan orchard in the Yaqui Valley. Rehabilitation was carried out for two consecutive years. In the first year a dose of 5 and 10 Mg ha‑1 was applied, while in the second year 2 Mg ha‑1 of gypsum was used. Two ridge washings were done after each aplication. The physico-chemical analyses of the soil were conducted following NOM-021-RECNAT-2000 during three years prior to and after the applications of amedment. Once the amendement was applied, the values of electrical conductivity decreased from 12.41 to 6.29 dS m-1, percentage of exchangeable sodium from 12.48 to 5.57 and sodium adsorption ratio from 10.54 to 4.88 at the depth of 0-30 cm. The use of agricultural gypsum and washing in a saline soil of the pecan orchard improved soil chemical properties using 5 and 10 Mg ha-1.