Availability of phosphorus to nursery plants

Abstract

Lopez-Bucio et al. emphasises the importance of phosphorus (P) in world agricultural production. They state that it is one of the most important nutrients limiting agriculture. In acid and alkaline soils, which make up over 70% of the world's arable land, P forms insoluble compounds that are not available for plant use. To reduce P deficiencies and ensure plant productivity, nearly 30 million tons of P fertiliser are applied every year. Up to 80% ofthe applied fertiliser is lost because it becomes immobile and unavailable for plant uptake. The production of plants in nurseries in Australia, South Africa, and New Zealand has a history of difficulties related to P nutrition. This is because these countries often have soils that are inherently low in available P and native flora is adapted to this. Often when these types of plants are grown with fertilisers containing P, they have a relatively high proportion of plants that are prone to P toxicity, particularly the Australian and South African floras. In New Zealand this may have been compounded by an agricultural nation which has grown up with the need to regularly apply superphosphate to the land, and in fact aerial topdressing was developed in this part of the world. This paper seeks to review the availability of P in soils and container mixes so that an improved understanding will aid the P fertilisation of nursery plants.