At the MicroFarm, we established six research zones based on paddock history and excessive wetness at establishment.

We have three paddock histories:

• two years of onion production with autumn cover crops of Caliente mustard
• two years of onion production with autumn cover crops of oats
• no previous onion crops planted after previous summer sweetcorn and autumn sown rye grass.

In each of these areas, we deliberately created sub-zones  by applying about 45mm of spray irrigation as a “large rain event”. This gave 6 individual zones to follow.

The impact of the artificial rainstorm is evident on images taken at the end of November.

Throughout the season we have monitored canopy development in both individual plots in each zone and across the whole paddock. 

A key method of recording plot canopy cover was using smartphone cameras, and using apps to covert to a Ground Cover Percentage. In particular this year we have used Canopeo and ELA. Most of the data we used was from the Canopeo app on an iPhone.

In 2015-16 we found a good relationship between processed phone images and leaf area index (LAI) which crop models relate to yield. This seems to offer a route to early yield prediction and opportunity to adjust management.

Early data from the monitoring plots show differences in development between the zones.

The canopy in zones that were given an artificial rainstorm after planting (“wet”) grew more slowly than the “dry” zones in all cases. The zones planted after the mustard cover crop grew more than those planted into oat cover crop plots. The zones not previously planted in onions had both the highest and the lowest average growth.

The paddock was mapped using the CoverMap iPhone app to measure ground cover at paddock scale. The new version appears stable even as light changes, a great advance on the previous one.

The two maps below show a slight increase in canopy cover were produced 6 days apart.  Red is low cover, Blue is high cover. The red strip along the bottom of the paddock is an area not adequately irrigated for the first several applications – the yield is severely compromised even though the irrigation was upgraded for the later 2/3rds of the season.