CAL-FERT: A simulation-based decision support system for precision fertilization of vegetable crops

The supply of fertilizers is often based on standardized protocols at pre-fixed rates that may lead to producing uncertainty and increased environmental impact in vegetable crops. Crop monitoring through remote sensors and tissue analysis represents a successful strategy for decision making in vegetable fertilization. However, simulation models are also useful and cheap tools that can be efficiently applied on homogeneous cultivation areas and that can be coupled with other monitoring techniques and technologies. CAL-FERT is a decision support system designed on an ExcelTM platform able to calculate the nutrient balance (N, P2O5 and K2O) of many vegetables and other herbaceous crops largely cultivated in the Mediterranean area. The software is freely downloadable for a broad audience from growers and technicians to researchers. The calculation is performed by estimating the main inputs and outputs (losses) for each of the three nutrients. The software framework consists of four main parts: 1) an interface for data entry by the user via a wizard procedure; 2) three different databases (i.e., for climate data, crops, and organic fertilizers), containing data and parameters necessary for calculations; 3) calculation algorithms of the nutrient balance and fertilization plan. CAL-FERT simulations are compared in the present work with field data collected in Val di Cornia (Tuscany, Italy), from experimental trials on spinach, to show its potentiality on real crops.