What are manures and litters in relation to soil phosphorus?

Manures and litters are significant sources of phosphorus in the soil, and their availability to plants can vary based on the type of material and how it has been processed. Different types of animal manures, such as those from cattle, poultry, or swine, have distinct nutrient profiles, including different forms and concentrations of phosphorus.

Processing methods also play a crucial role; for instance, treated or composted manures may have phosphorus that is more readily available to plants than raw manure. Some forms of phosphorus in manures may be more soluble, making them more accessible for plant uptake, while others may be more stable and release their nutrients slowly over time. This variability means that the effectiveness of manures and litters as phosphorus sources is influenced by both their source and treatment.

In contrast, the other options incorrectly characterize manures and litters. The idea that they are sources of insoluble phosphorus that cannot be utilized by plants is misleading, since manures contain a mix of soluble and insoluble phosphorus. Claiming that they contain only organic matter with no phosphorus overlooks the essential role of manures in providing key nutrients, including phosphorus. Suggesting that they are primarily composed of nitrogen compounds only disregards their balanced nutrient composition, which includes significant