A rapidly expanding poultry production industry with associated poultry litter (PL) is located in close proximity to high yielding irrigated cotton in the Murrumbidgee Valley of south eastern Australia. Estimates indicate that ~200,000 wet tonnes of PL generated in the district annually, contain about 3500 tonnes of plant available N, 1440 tonnes of P, 3360 tonnes of K and 76 tonnes of Zn, as well as micronutrients, liming effects and carbon. These amounts alone are sufficient to support approximately 12,000 ha of high yielding irrigated cotton production when a 250 kg fertilizer N ha-1 rate is applied. Since urea is synthesised from fossil fuels via the Haber process and inorganic P fertilizers are mined from finite resources, there are environmental advantages to being able to use the abundant nutrient rich poultry industry wastes generated locally as an alternative fertilizer. Since the poultry industry needs to dispose of the wastes and freight distances are relatively short (within 50km) there is also a potential economic advantage for farmers. However, there are unknowns for farmers when using PL compared with mineral fertilizers. The main issue is caused by product variability and therefore unpredictability of performance in high yielding irrigated systems. Typically farmers are applying ad hoc amounts of PL, mainly for longer term soil sustainability outcomes in addition to mineral fertilizers, without clarity on tangible productivity benefits. 

Using on-farm commercial scale field trials and small plot studies the project has investigated how PL generated around Griffith, Leeton and Darlington Point, NSW can be managed most effectively in a number of farm case studies, examining particular scenarios that are most applicable to soils and farming systems of the southern cotton growing region, namely:

1. How nutrients contained in PL may substitute for urea-N and inorganic P to optimise yield, lint quality, N efficiency and soil health on Transitional Red Brown Earths and Grey Vertosols, typical of the Riverine Plain. Estimating rule of thumb cost benefits using  2018-2021 cotton, freight, fertilizer and PL prices.
2. The effectiveness of PL in restoring fertility and reducing field variability in heavily cut areas of landformed fields for incorporating PL spreading into precision application programmes. 
3. Tracking the fate of fertilizer N when applied in combination with PL amendment to determine improvements in NUE and using in situ field probes, the impact of PL on temporal nutrient availability. 
4. Investigating the impact of PL on improving P nutrition for cotton in soils prone to sub-soil sodicity. 
5. Soil health under poultry litter amended and non-amended cotton systems of the Riverina