Effect of bicarbonate and phosphate on iron‐chlorosis of grape‐vines with special regard to the susceptibiliy of the rootstocks. I. field experiments

Abstract

In field experiments on three different locations it was looked for indicators inducing iron chlorosis on grape‐vines grafted on two rootstocks: Couderc 3309 (susceptible) and Kober 5 BB (resistant). Investigating the soil it was found that the bicarbonate concentration in the rooted soil depth (20–60 cm) did not differ between chlorotic plants and the green ones, whereas the phosphate concentration under chlorotic plants is significantly higher. There exists no differences in the iron content of the soil.

Calculating stepwise regression functions it was possible to discriminate between chlorotic and healthy plants. Under chlorotic plants bicarbonate effects the iron availability to 30% for resistant, and up to 52% for the susceptible rootstocks.

Analyzing green and chlorotic leaves it could be shown that Ca and K content is significantly higher in chlorotic ones. Typical is also the significant increase in total iron content.

Key words:

• Field experiments
• iron chlorosis
• grape‐vines
• rootstocks
• multiple regression
• bicarbonate
• phosphate