Strategies for Enhancing Phosphorus Efficiency in Crop Production Systems

Abstract

Phosphorus (P) is the second important key element after nitrogen as a mineral nutrient for crop production. An adequate supply of P during early phases of plant development is essential for the root establishment and growth as well as for laying down the primordia of plant reproductive parts. Although abundant in soils in both organic and inorganic forms, P is the least available to plants due to its high fixation in most soil conditions and slow diffusion. Therefore, P can be a major limiting nutrient for plant growth on many soils across the world. Agricultural productivity will be lower without P, and consequently less food will be produced per unit area of land, especially in the least developed and developing countries where access to P fertilizers are restricted due to the rising costs of P fertilizer. Therefore, P is essential for the intensive agricultural production systems and thus contributes significantly to the present and future global food production and security. P is usually added to soil as chemical P fertilizer to satisfy the nutritional requirements of crop; however, plants can use only a small amount of this P since 75–90% of added P is precipitated by metal–cation complexes and rapidly becomes fixed in soils. There is an increasing concern about the sustainability of P in agricultural production systems largely due to shortage of inorganic P fertilizer resources and environmental effects of agricultural P use beyond the field in the form of eutrophication. Such environmental concerns have led to the search for sustainable way of P nutrition of crops. Enhancing the efficiency of P in plants can be obtained through improving P acquisition by plants from the soil, internal plant utilization, or both. Hence, this review mainly focuses on three aspects: (1) we provide a brief overview on the holistic understanding of P dynamics in soil, (2) we discuss the role of microorganisms in increasing the availability of P to plants, and (3) we speculate on sustainable management strategies to enhance P use efficiency (PUE) in modern agriculture. Sustainable response strategies are required to improve PUE and recovery in order to cover the losses from the entire food production and consumption chain. An integrated strategy rather than a single strategy should be employed to enhance PUE and to recover unavoidable P losses.