Farming in deserts can be challenging. Soil surrounding Yuma in Arizona is predominantly sandy, which tends to drain quickly and can have low organic matter, making careful management of nutrients and water important for crop growth. A study carried out by the US Environmental Protection Agency on the effects of using biosolids to replace chemical fertilisers in farmland reported that biosolid applications reduced the need for conventional fertiliser in the trials. According to the EPA's Biosolids Recycling: Practices and Benefits report, applying 8 dry tons of biosolids per acre to sandy irrigated soils near Yuma, Arizona, reduced chemical fertiliser requirements to about one-quarter of normal levels during the first year after application. The report further states that by the third year of biosolids use, no supplemental chemical fertiliser was required.
The functioning of the trial
