Agro-ecology is the unpretty name for the new wave of small rural enterprises that are required to develop and secure local food supplies, diversify employment in rural areas and to restore and improve bio-diversity and soil fertility. Unfortunately for planners these enterprises require living on the land which often implies an application for anew dwelling (to be considered under Appendix A of PPS7 until this is superseded by the couple of lines in the NPPF that refers to the essential need for the new dwelling.
For the last thirty years these isolated and 'low impact dwellings' have caused problems for planning authorities and the record of local and appeal decisions is extremely lumpy and not helpful to those looking for a pattern and the level of consistency and predictability we deserve.
The urgent need for substantially more of these small-scale rural enterprises can be found in the relevant literature (start with the web site of the Campaign for Real Farming and read anything if not everything written By Prof Tim Lang). When we have the presumption in favour of sustainable development it might not require the work of a genius to show that organic smallholdings are sustainable in accordance with many of the measures currently understood. However, there might not be a good case for these to be scattered across the countryside in terms of sustainability or landscape impact. There seems to be every reason for local planning authorities to take the lead from the 'presumption' and to place enabling policies in their development frameworks so that clustered smallholdings in the urban fringe will normally be permitted.
In fact the growing of food and keeping or livestock are only part of sustainable lifestyles and local development frameworks should recognise and privilege co-housing as the only form of new residential development capable of meeting low carbon targets. The presumption against unsustainable development will, when translated into local planning policy, deter the use of the urban fringe (and all greenfield sites) for conventional models of housing (and growing).
As soon as the NPPF is published (with the sustainable development presumption) the work will begin to establish the principles of sustainability as far as these are not found in the NPPF. The standards must be raised by those involved in the low carbon economy and organic food movements, so as to effectively outlaw (as indeed this might be the legal effect of a presumption in National policy) conventional residential schemes.