Blending agroforestry, poultry manure and biochar to develop fertiliser and soil carbon for broadacre farms – Living Farm Results Report

This trial was conducted in York, to evaluate the application of different forms of chicken manure as a fertiliser source for the growth and yield of wheat (cv Corack).

The chicken manure used in this trial was naturally high in urea, but also contained lower amounts of other macronutrients including phosphorous and potassium. As a result of the higher nitrogen content, it was decided to compare this to an industry standard form of applied nitrogen (Sulphate of Ammonia (SOA)).

Two forms of manure were trialled: 

• A standard form of manure obtained from the bedding materials of chicken broilers. This product was a mixture of sawdust (from forestry thinnings) and chicken manure which had been macerated into a uniform powder with a similar consistency to sawdust.
• A mixture of urea, manure (as above) as well as biochar which had also been produced from forestry thinnings. Urea was added to the second form to increase the nitrogen component.

Because the manure blends used in this trial also contained other macronutrients, it was decided that phosphorous and potassium should be applied to seven of the 11 treatments in non-yield limiting quantities to ensure that the nitrogen benefit from each product could be adequately isolated and compared.

Method

The following treatments were applied:

There were four replicates in a complete randomised block design. Plots were 15m x 2m. Soil type was sandy quartz loam. 

NDVI Readings and crop stand counts, vigour, yield and quality were measured. Crop vigour and NDVI were measured at four and nine weeks after sowing. Crop stand counts were collected at four to six  weeks after sowing.

Results

There was no positive or negative effect on plant establishment between any of the treatments, and similar vigour was recorded for all treatments. However, there was slightly lower vigour in the 'no fertiliser' treatments. The background nutrients in 'chicken manure treatments' appeared to have given a vigour response when compared to SOA alone. There were no differences in NDVI at four weeks after sowing. NDVI readings from nine weeks after sowing correlated strongly with the vigour scores. There were lower NDVI readings at six weeks after sowing from the 'no fertiliser' and 'manure only' treatments. Yield results also correlated to the vigour and NDVI reading nine week after sowing.

Discussion

Although no significant differences between the treatments were found, this is an encouraging result as it indicates that chicken manure mixtures can be used as a replacement to the traditional inorganic fertiliser - Sulphate of Ammonia. Outside of the direct benefits of its use as fertiliser, there are three additional potential outcomes:

1) it will act as a market for currently non-utilised forestry products and thinnings

2) it will assist in the disposal of chicken manure and bedding

3) it will return some of these nutrients and carbon back into the regions where they were originally sourced from.

It must also be noted that this was a short trial and differences between the treatments may have become significant over a longer time period.