This is an important toolkit, from the International Consortium for Agricultural Systems Applications for agricultural scientists, which has since the 1980s integrated a number of routines to handle 27 crops, using US data, with various economic risks and environmental impacts associated with irrigation, fertilizer and nutrient management, climate change, soil carbon sequestration, tillage routines climate variability and precision management.

This land evaluation decision support system for agricultural soil protection has a useful on-line demonstration. Given extensive data on soil characteristics and climate, which are well parameterised for Spain, it provides decision support in English and Spanish for soil use, including crop yield, natural fertility, suitability for forestry or engineering, risk of contamination, compaction and erosion risk.

A model costing GB£300 that can be used to investigate effects of cropping regimes to estimate crop yields and gross margins, parameterised for many European crops and with nitrogen leaching and herbicide resistance as environmental considerations.

Modelling in Hungarian of maximum return based on fertilizer inputs without consideration for environmental consequences of greater inputs.

An agricultural support for farmers in Hungarian

This is multi-year multi-crop daily time step simulation model for agronomists and soil scientists to study soil, water, nitrogen, growth, yield, rotation, erosion and residue management, with over 80 tillage options.

This model from the US Department of Agriculture, based on combination of modules from several previous models, works with TOPAZ GIS to simulate flows of nutrients and pesticides from crops into ponds and streams.