The Scale and Complexity of Salinity Impacts on Sri Lankan Rice Farming Systems: Actionable Insights

Saline-affected rice (Oryza sativa L.) production environments in Sri Lanka can be divided into three categories including: late-season salinity in irrigated mega-cultivation environments during the minor cultivation season where soil EC ≥7 dSm−1, late season salinity in rain-fed farming systems in the west, southwest, and eastern coastal line during the minor cultivation season where soil EC ≥20 dSm−1, and early season salinity in selected irrigated and rain fed sites during major and minor cultivation seasons as a result of residual overload of salts that was not washed off due to inadequate rain. In the west and southern coast early season salinity salinity can exceed EC ≥12 dSm−1. The proposed zones of saline-afflicted production environments permit designing of target ideotypes and locally adapted rice varieties. Accordingly, high yielding, 3 to 3.5 months duration varieties that are tolerant at >7 dSm−1 are recommended for intensive irrigated farming systems affected due to late season salinity (panicle initiation stage of the crop, PI); high yielding, 2.5 to 3 months duration varieties can avoid late season salinity in intensive irrigated farming, and varieties tolerant up to EC = 12 to 20 dSm−1 throughout the crop life including seedling and PI stages can target saline affected, semi-subsistence rice cultivation in rain-fed systems. In fact, secondary salinization in local rice farming environments is resulting from interaction among multiple factors; therefore, system-level interventions are necessary to manage the impacts