The impact of poultry manure and rock phosphate in heavy metal and nutrients concentrations on ryegrass grown in two Cambisols

Ecofriendly amendments are willing to maintain crops productivity because they are a good source of organic carbon for promoting soil biology. However, there are some counteractions led might by inputs of ecotoxicological elements to soil-plant environments. This study evaluated the effects of poultry manure (PM), rock phosphate (RP), and their combination (PMRP) on the growth, nutrient uptake, and heavy metal (HM) accumulation in ryegrass grown in two soil types: moderately acid and alkaline. A growth chamber experiment was conducted over seven weeks to assess the impact of these amendments on nutrient and heavy metals concentrations in soil, shoots, and roots. Results indicated significant increases in potassium concentrations in both shoots and roots with the PMRP treatment, particularly in moderately acid soil. In alkaline soil, PM treatment led to substantial increased in copper, manganese, nickel, lead, and zinc concentrations, raising concerns about heavy metal accumulation. The principal component analysis further highlighted the enhanced nutrient availability and potential risks of heavy metal accumulation with PM and PMRP treatments. The findings underscore the importance of balanced fertilization strategies that optimize nutrient uptake while minimizing environmental risks. This study contributes to the understanding of integrated fertilization strategies, emphasizing the need for careful management to ensure sustainable and safe agricultural practices.