Use of SIMS_(DAIRY) modelling framework system to specify sustainable UK dairy farms

摘要

Sustainability in UK dairy farming is no longer secured by traditional management focused on production of commodities. Society awareness, legislations and competing markets demand farming systems which can deliver multiple attributes such as: clean environment, high biodiversity, picturesque landscapes, good animal welfare and high quality of product and soil. In order to study this complex system, a new model (SIMS_(DAIRY)) has been developed. We demonstrate the use of SIMS_(DAIRY) to explore the economic viability of technical or structural system changes aimed at improving sustainability in existing UK dairy farm types. Management factors (i.e. manure, fertiliser and diet), acting singly, or in combination, are evaluated in such farms by a multigoal-seeking procedure (evolutionary trajectory towards sustainability). The following goals are sequentially achieved as this trajectory progresses, compliance with: (i) NVZ_(170) legislation, (ii) Nitrate Directive 91/414 (11.3 mg L~(-1), (iii) Gothenburg protocol (NH_3 reduction), (iv) Kyoto protocol (N_2O and CH_4 reduction), (v) P eutrophication limits (100 p.g L~(-1)), (vi) milk with beneficial properties for human health, (vii) acceptable animal welfare and (viii) enhanced biodiversity and landscape. Although results from this exercise pinpoint the difficulty in achieving overall sustainable dairy farms under existing market/subsidies systems in the UK, they also show that some combinations of management factors may offer substantial scope forimproving sustainability with no economic penalties.