Barrie Ridler developed the concept of farm systems modelling at No.4 Dairy while Senior Lecturer in Farm Management at Massey University. Subsequent farm ownership and management enabled on-farm model testing for practical application and profit. Incorporation of new computing platforms and design development followed with a number of rewrites and additional inclusions including the causes and quantification of N excreta and GHG gas. This model provides insights into the practical consequences of environment constraints on farming profitability.

Thirty years of effort focused on farm production systems management has given Barrie a wide ranging understanding of farming. Research and on-farm applications of the "GSL" farm systems modelling approach confirms the importance of marginal analysis for any management change to ensure viable farm business. Barrie has published numerous farm systems papers and brings a unique combination of scientific, practical, educational and farm management experience to the group.