Site-specific nutrient management (SSNM), as developed for rice (Oryza sativa L.) through partnerships of the International Rice Research Institute (IRRI) with organizations across Asia, provides scientific principles for determining field-specific fertilizer nitrogen (N), phosphorus (P), and potassium (K) requirements for cereal crops. These SSNM-based principles enable the determination of crop requirements for fertilizer N using a yield gain approach, the distribution of fertilizer N to match critical crop growth stages, and the determination of crop requirements for fertilizer P and K using a field-level nutrient balance approach. The uptake by farmers of improved nutrient management based on SSNM requires transforming the scientific principles into locally adapted tools that enable rapid development and implementation of nutrient management practices that match field-specific cropping conditions. We used recent advances in information and communication technology (ICT) and mobile phones to develop Web and mobile phone applications of "Nutrient Manager for Rice" (www.irri.org/nmrice), which transform the science of SSNM into guidelines matching the field-specific needs and conditions of a farmer. Nutrient management guidelines provided by "Nutrient Manager" are calculated by a `model' residing on a cloud-based server. Information obtained by the ‘model’ from answers of farmers to questions about their location-specific cropping conditions can be supplemented with Internet-based soils information to enhance the robustness of nutrient management guidelines provided to farmers. Field trials with rice reveal no relationship between soil analyses for soil N, P, or K status and field-measured rice response to the added nutrient. There is consequently an immediate need to identify soil information most indicative of crop requirements for supplemental nutrient in small landholding with large spatial and temporal variations in management, nutrient balances, and yield.