Phosphorus Leaching During Potato Production in Coarse Soil

In potato production systems, runoff and erosion are major loss routes of phosphorus (P), while P loss through vertical leaching has been considered insignificant due to the poor mobility of P in soil. However, reduced water and nutrient retention capacity in coarse-textured soil as well as shallow root system of potato may result in significant P leaching beyond potato rooting zone, leading to lower P-use efficiency in potato production and increased environmental risk. The objective of this study was to evaluate phosphorus leaching in coarse soil during potato production under varied phosphorus application rates, by collecting leachate from 60 cm deep soil. Results indicated that accumulative P leaching during the potato production ranged from 0.61 to 4.67 kg ha-1, P concentration in leachate solution could reach 3.41 mg L-1, and it increased significantly with increasing P application rate. This high level of P leaching is a concern both environmentally and agronomically, and points to the importance of developing P fertilizer management aimed at diminishing P leaching and improving P-use efficiency in potato production in coarse soil worldwide.