Sustainable farming a goal for us all

We aim to improve natural resource management (NRM) aspects such as soil quality, soil health, good biodiversity (including adding strategic clumps of trees), clean water runoff into dams and creeks and prevent soil erosion.

Australia feeds about 100 million people (home and export) compared to pre-European settlement of perhaps one million.

Much of that production occurs on land low in natural soil fertility and in relatively low erratic rainfall areas.

It is unrealistic to aim to have all our land in a “natural pristine condition” as big changes have, and will continue to, occur to maintain and improve productivity while at the same time preserve and improve our land base. 

Definition of “sustainability” needs to be science-based and not the preserve of groups promoting this or that practise or/and product. It is always wise to question a given “sustainability” claim by where are the facts to support such claims. 

There are lots of examples of how farmers are making great progress in improving their land and commonly these go hand in hand with improving production.

For example, a generation ago most crop growers worked their land with ploughs and cultivators several times per crop plus full disturbance sowing.

Soil erosion was a big problem and soil structure with associated depleting soil organic matter (OM) was an enormous issue.

Zero or no-till adoption with occasional cultivation has largely arrested declining soil structure with some research, especially in wetter areas, indicating gradual improving soil OM.

Erosion has largely been eliminated when zero till combines with stubble retention. Correcting soil deficiencies like nitrogen contributes to greater OM (as well as production).  

Research supports quality pastures when combined with good management build soil organic matter plus improved soil quality such as biological activity.

Soil fertility is closely related to soil health, organic matter levels and therefore soil carbon.

Part of sound grazing includes retention of adequate ground cover. Some research suggests adequate ground cover is a key factor and commonly more critical than any particular grazing management system. 

Other research shows that for many perennials, especially species like phalaris and lucerne various degrees of rotational grazing are important for the perennial plants survival.

For example, in late spring summer early autumn after grazing lucerne plants draw down on root reserves for the next fortnight and within around 40 days have replenished these reserves.  

Research shows that best fertilisers for pasture production as well as soil health aspects like biological activity and OM are those that supply missing soil deficiencies, like phosphorus and sulphur, in available forms and in sufficient quantities.

These products can include animal manure (for example feed lot or poultry) provided applied at sufficient rates, as well as products like single superphosphate.

For example a long running Department of Primary Industries trial at Ulamambri SF45 super caused  a doubling in organic matter, higher biological activity, water infiltration rate seven times better and ground cover improved from 60 to 100 per cent when compared to no fertiliser. Production more than trebled.

Superphosphate does not acidifies soil if used in combined with perennial pastures, native or introduced species.

What causes acidification is leeching of nitrogen in an annual cropping and pasture system, product removal (more significant with cropping) and to a degree soil organic matter build up.

In some soils sustainability does include periodic lime use. 

Fertilisers like superphosphate do not cause pastures to be dependent on them and be lazy as far as extracting other sources of soil elements like sulphur and phosphorus.

Well managed perennial pastures also better compete with troublesome weeds, an important NRM aspect.