Nutrient Management Research Database

A  direct  impact  of  increasing  solution  Zn  concentration  on  P  uptake  in  potato  was  clearlyobserved in these studies. While Zn content increasedin all plant parts as solution Zn increased,P  concentration  in  both  top  leaves  and  middleleaves  and  stems  declined  with  a  concomitantincrease of P in roots. This suggests a P/Zn complex formation in roots preventing movement ofP  to  the  tops  of  plants  under  high  Zn.    However,  contrary  to  expectations,  no  direct  impact  ofincreased  solution  P  on  Zn  uptake  or  distribution  in  potato  was  observed.  Instead,  increasedsolution P resulted in accumulation of Mn in potato roots which may beindirectly impacted byZn in potato.  Therefore, although high P levels inpotato did not directly reduce Zn content orcause Zn deficiency, they may reduce the activityof Zn by interacting with other micronutrientssuch as Mn. 

Potatoes are often grown in high pH soils that can have limited phosphorous (P) availability. P fertilization, however, can decrease zinc (Zn) availability.

This hydroponic experiment was performed to elucidate the relationship between P and Zn.

Potatoes were grown either with constant P levels and varying Zn levels or vice versa.

Plant growth and nutrient cocnentrations were measured.

Moderate levels of Zn and P resulted in the healthiest plants. While low levels on Zn stunted plant growth and high levels resulted in yellowing, mottling, curling, and leaf burn. Low P resulted in stunted growth as well, and a slight decrease in growth was observed at high levels of P along with symptoms similar to those observed at high levels of Zn.

Plant P concentrations in the top and middle leaves were decreased with more Zn was added.

No clear relationship was observed between plant Zn levels and P availability.

The concentrations of nutrients used in this study do not easily translate to field application rates.