Enhancing early root growth to exploit indigenous soil P and fertilizer P

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Bindraban, Prem S.
A.L. Smit
M. Blom-Zandstra
A. van der Werf
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Phosphorus (P) availability is a significant constraint in global crop production. Current annual mineral P fertilizer input exceeds the actual uptake by crops, leading to P accumulation in soils and inefficient resource utilization. This study investigates the hypothesis that enhancing early plant growth can improve P uptake from indigenous soil resources and fertilizer P. The low recovery rate of applied mineral P fertilizer, typically less than 30%, is attributed to its binding with soil complexes, making it less available for plant uptake. The soil solution often exhibits very low P concentrations compared to root concentrations, emphasizing the need to increase P availability or enhance plants' ability to extract P from soil complexes. In regions with P-deficient soils, substantial P applications are required to improve fertility and enhance crop yields. Similarly, unintentional excess P application occurs in areas with nutrient surpluses, resulting from concentrated livestock production and subsequent manure application. These fertile soils can contain excessive total soil P, far exceeding the annual crop uptake. If these soil P reserves were fully available to crops, they could sustain agricultural production for several hundred years. Case studies in Africa demonstrate the relationship between total soil P content and maize grain yield, indicating the potential longevity of soil P reserves in sustaining production. Even soils with relatively low fertility levels have sufficient total P content to support production for over a hundred years. However, the assumed P content in crop biomass may be lower at these sites, implying even longer sustainability. By enhancing early plant growth, this study aims to improve plant P uptake efficiency, effectively utilize accumulated soil P, and optimize the uptake of newly applied P fertilizers. The findings of this research contribute to developing strategies for sustainable P management, promoting efficient resource utilization and improved crop productivity.
Integrated Soil Fertility Management, Decision Support Systems, Awareness-raising, Agricultural productivity
A.L. Smit, M. Blom-Zandstra, and A. van der Werf and P.S. Bindraban, 2013. Enhancing early root growth to exploit indigenous soil P and fertilizer P. VFRC Report 2013/4. Virtual Fertilizer Research Center, Washington, D.C. 36 pp.; 4 tables; 6 figs.; 98 ref.