By Chris Wallwork, Agrii Technical Manager (Vegetables)

Phosphorus is required early within vegetable crop development to encourage rooting, essential for further water and nutrient exploration of the rooting zone.

As a result, it is most vital to the crop early in the season but this is when it is most difficult for plants to extract it from the soil due to the colder weather.

Products such as Agrii-Start Release have been developed to increase phosphorous availability in soil and tackle the issue of phosphorous binding with calcium in soils.

Availability can be impaired by calcium content of soils, whereby the phosphorus in locked up within calcium phosphate compounds or by low soil temperatures. This year, Agrii has conducted several trials using Release that have shown significant yield increases in a wide range of vegetable crops.

Agrii-Start Release trial

David Townley set up an Agrii-Start Release trial in March 2021. The spring was cold and dry and the soil was high pH with P index 3.7, so Release had a good chance of showing benefits.

The trial included baby leaf spinach, iceberg lettuce, bulb and salad onions, leeks and carrots. The plots were sprayed either with Release shallow incorporated pre-drilling / planting or as a surface spray after drilling but pre-planting. It was replicated to allow statistical analysis.

The incorporated Release treatment gave impressive yield increases for all these crops. Yields increased between 16 and 42% above the untreated plots and were statistically significant in all cases. The yield increases from the non-incorporated treatment
were lower, but might have been better in a wetter season.

David cautions against expecting such strong results in commercial crops. “These yields were measured on a single crop row grown with wide inter-row spacing so yield benefits in field crops may be lower. We’re planning trials in commercial crops in 2022”. But the consistently positive results do show that Release can be valuable in a wide range of vegetables.

The photograph shows the effect of Release shallow incorporated before planting cauliflowers. This was a single plot (unreplicated), but the result is consistent with our other work.
Release treated crops are on the left of the picture and untreated crops are on the right.

Whilst the results of these small plot trials are certainly encouraging, it’s important to recognise that a larger commercial field trial may not replicate the same increase in yield as seen here. However, Agrii hope to conduct more trials using Release on commercial crops in the coming year