Suitable methods of tillage for the farm
The trial described here for conducting on-farm compares wheat crops grown under three tillage systems: full or conventional tillage, minimal tillage and zero tillage.
First, it checks whether yield can be maintained using standard sowing dates but with the reduced effort and reduced expenditure associated with fewer tillage operations.
Second, it uses reduced tillage to open up the possibility for timelier sowing.
The trial also introduces a simple method for assessing how much of the rain falling on the crops is wasted or leads to soil erosion and how much goes towards producing crop growth. It uses the method to compare the three tillage systems for water efficiency.
It should not be attempted if aggressive local weeds cannot be controlled other than by full tillage. Nor should it be approached with the expectation that minimum and no-till approaches will increase yield unless they lead to timelier planting.
The aim will be long-term protection of the soil resource; reduced machinery wear and savings in fuel costs and labour.
A likely conclusion from this trial is that the farm will benefit from a mix of several tillage approaches. Other chapters you might need to refer to are those on choosing the right variety x sowing date, optimizing a cropping sequence for the farm, nitrogen use and crop establishment practices.
Which farms would benefit from this tillage experiment?
Those farms with low rainfall where normal cultivation results in high evaporative or runoff losses and therefore reduced soil moisture;
those farms where rain falls in bursts of high intensity leading to run-off;
those on steeply sloping land with associated problems of water erosion;
those with poorly structured soils that readily turn to dust when cultivated under dry conditions or form large clods when cultivated wet;
those with soils that readily form plough pans that are impenetrable to roots or with soils that become compacted under heavy wheeled traffic;
those farms requiring an early start to the season when weather may commonly preclude normal multi-pass tillage operations.
Tillage practices: some background
Tillage has been used for millennia to prepare the soil prior to sowing many of the annual grain crops. It involves applying power to break up and rearrange the entire topsoil structure. It has the primary aim of destroying weeds and pests but is also important for incorporating, redistributing or releasing nutrients and making the soil texture suitable for seed sowing, seed germination and for easy penetration of seedling roots.
The English word “tillage” is derived from the Old English “tillen” which means “to toil”. With only human or animal power available, it took a long time and much toil to till even moderate-sized areas of land. When tractors became available, larger areas could be cultivated per person.