Phosphorus use efficiency, tuber yield and quality in potato processing varieties grown under different P levels in the Argentinian Pampas

Abstract

Summary

In the southeast region of the Argentinian Pampas (province of Buenos Aires) more than 32,000 ha of potatoes are grown annually, being this region the most important at country level regarding production for processing. To achieve high yield and quality, crop demands in term of resources are high, mainly regarding water and nutrients. To assess the effect of different P rates (0, 75, 100, 125 and 150 kg ha^-1) on Phosphorous Use Efficiency (PUE), tuber yield, quality, and economic return, a field trial under central pivot irrigation, with cultivars Daisy and Innovator, two of the main French fry processing varieties, was carried in the southeast region (Balcarce, 37º 45' SL; 58º 18' WL, 130 m asl) in a typical Argiudol soil. Fertilizer rates were applied at planting while all other management practices were applied as normally done in the area.

In Daisy, increasing P rates increased dry matter accumulation in haulms and tubers, mainly in the period up to 90 days after planting (DAP). In Innovator, increasing P rates lead to a significant increase in haulm and tuber growth. In both cultivars higher P rates increased P petiole content early in the season (43 and 69 DAP). In Daisy the higher P rates increased P level both in haulm and tubers up to 90 DAP. A similar pattern was observed in Innovator, but in this variety, the higher the P rates the higher the accumulated P, mainly in the tubers. In Daisy the increasing P rates decrease PUE at the higher P rate. In Innovator the response to P rates was much higher and this variety resulted more efficient in P use than Daisy. In Daisy higher P rates increased tuber yield early in the season and by 90 DAP yield in the higher P rates almost double that of the control. In Innovator, increasing P rates lead to a higher tuber yield. Early in the season yield in the control treatment was 30.75 t ha^-1 while in the higher P rate the yield was 48.09 t ha^-1. The same pattern was observed late in the season, where the yield was lower in the control treatment when compared with any of the P rates, especially at the final harvest. In Daisy, higher net return was estimated at 75 kg P ha^-1. On the other hand, in Innovator while P rates increase, also the net economic return present higher value. Then, for the Argentinian Pampas a different fertilization approached must be followed to improve P use efficiency and crop return in these two varieties. Lower levels of P can be used in Daisy which will not impact on final tuber yield, while in Innovator higher levels of P are required to achieve higher yields and increase crop net return.

Key-words: Potato, Tuber Yield, Phosphorus Use Efficiency, Economic Return