Maximising cropping yields involves using a combination of latest research data with almost timeless “common sense” information, sometimes centuries old.
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Sowing on time with a trend to earlier sowing with slower maturing varieties, controlling weeds early, rotations for disease minimisation and sometimes reduced pest risk, sowing at the right depth, storing fallow moisture (combines with timely fallow weed control), timely harvest and checking soil fertility (via soil tests and nutrient budgeting), are all basic cropping aspects critical to maximising crop yield.
In my more than 50 years as an agricultural advisor/researcher/consultant, I reckon the best farmers are those that do things on time.
Commonly it means being ready to move quickly should weeds need spraying, crops sown or harvested, or whatever the vital job is.
Having the latest equipment, variety or other technology is important, but no where near as critical as doing things on time.
Rotations, a part of forward planning, although sometimes requiring late modification should seasonal conditions be difficult (for example no timely rain for an early sowing rotational crop choice), is today a vital part of maximising crop yields.
Our European forebears were well aware of the value of rotations and were commonly used more than 400 years ago, and in a general sense such knowledge remains critical today.
Specific issues relevant to the advantages of rotations, include endeavouring to minimise diseases weeds and best.
For example, we aim to minimise wheat and barley soil and stubble borne diseases like common root rot, take all and crown rot via including in the rotation pulse or broadleaf crops like canola or others.
Fallow grass weed elimination is also part of the control strategy.
Cereal nematodes are relatively recently appreciated soil pests, where rotations can play a big part in their control.
Knowing which is the nematode, or group of nematodes, and the resistance rating of rotation crops is also important.
Plant breeders are also improving on variety tolerance to these pests, also an important party of the control strategy.
Research over many years and environments, supports the value of fallow moisture storage for almost all cropping areas of Australia.
That applies to summer and winter crops, almost all soil types and includes high medium and low rainfall environments.
The recent droughts have reemphasised that even so-called high rainfall cropping areas (much of the cropping being dual purpose ones) commonly have moisture deficits in the crop growing period, requiring supplementation from fallow moisture.
Our European forebears were well aware of the value of rotations and were commonly used more than 400 years ago, and in a general sense such knowledge remains critical today.
- Bob Freebairn
This past/current drought has also emphasised the need for stubble retention, to eliminate or largely reduce the impact of wind erosion and water erosion had the drought broken via storms.
Soil organic matter (that includes carbon) and nutrient loss, has often been enormous with years of building up undone.
Equally critical to timely fallow weed control, is that fallow weeds allowed to get away also use soil nitrogen.
Commonly this nitrogen is not available, or less available to the following crop, although it can breakdown and be released back to the soil nitrogen pool.
Soil tests and trials indicate soil nitrogen for the next crop is lower by around 40 kg/ha or more compared to timely fallow weed control.
Timely weed control commonly means an extra fallow spray or two.
Weeds are best controlled when young and sappy and kills on difficult to control weeds also are mainly far better from an early timely treatment.
In summer a day or two, not a week or two, can be the difference between good weed control and poor control.
Part of good farming today also includes a good knowledge of crop variety features other than just maturity, quality and yield ability.
Resistance levels against a multitude of diseases like for wheat the three rusts, yellow leaf spot and septoria (especially for the south), and two crop damaging species of root lesion nematodes is also important.
Next week: Soil constraints are best dealt with via good top and sub soil analysis. Research is required to improve yield on many problem situations.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.
