image expired

The origins of E-W sowing

Crop row orientation is certainly not a new technique! It has been researched in a range of crops (from wheat to grapevines) in the USA from the 1950s. Professor Stephen Powles, AHRI Director, was first exposed to the concept during his days as a crop science postgraduate student at Michigan State University, where one of his professors was conducting E-W versus N-S soybean planting. For many years this technique was not relevant in Australian broad-acre cropping because our growers sowed their fields round and round and not up and back.

Fast forward to 2002 in Western Australia where DAFWA researchers Shahab Pathan, Abul Hashem and Catherine Borger began investigating the concept in wheat and barley at Avondale and Merredin. This ultimately all led to further research being conducted by Catherine between 2010 and 2012 as an AHRI / DAFWA collaborative project. With up and back sowing now common in Western Australia, the culmination of all of this research is now very relevant.


Dr Catherine Borger conducted research on several aspects of crop competition between 2010 and 2012. She found, as others have in the past, that high cereal seeding rates increased crop competition with weeds, reducing ryegrass seed production, and that barley competes more with weeds than wheat. However, her research into crop row orientation was of particular interest as it represents free weed control.

Ryegrass seed production

Ryegrass seed production was halved by sowing east-west compared to north-south. Catherine found an average ryegrass seed production of 2968 seeds/m2 in east-west crops, compared to 5705 seeds/m2 in north-south crops. The only exception was Katanning in 2010 where the ryegrass emerged two weeks after the crop, ensuring that the crop was highly competitive (regardless of crop orientation or seeding rate).

These field trials were conducted at DAFWA Research Stations located in Merredin, Wongan Hills and Katanning, in 2010 and 2011. In 2010, three trials investigated crop row orientation and seeding rate (Wyalkatchem wheat at 60 or 120 kg/ha). In 2011, trials investigated orientation, crop type (Wyalkatchem wheat or Buloke barley) and seeding rate (50 or 100 kg/ha). Of particular importance is that ryegrass seed production was reduced despite dry years (such as Merredin 2010).

Light availability

Sowing east-west in winter in southern Australia reduced the light available to annual ryegrass in the inter-row compared to north-south crops at all measured growth stages of ryegrass.

Soil Moisture

Soil moisture was also influenced by crop row orientation. East-west sowing reduces the amount of sunlight hitting the soil surface which in turn reduces evaporation.

Click here to see the full report.