Influence of snow melt water on the content of mineral nutrients in the leaves of broad bean (Vicia faba L.) under snow cover with reference to snow damage

The content and distribution of potassium (K) and calcium (Ca) in the leave s of broad bean during the snow cover period were investigated to clarify t he role of snow melt water in snow damage. The experiments were carried out under the conditions where air temperature was usually above 0 degreesC an d snow had been melting during the snow cover period. The melt water with a n average pH of 4.4 contained Cl-, SO42- and NO3-. The plants were cultivat ed in open fields or inside tunnels covered with non-woven fabric to decrea se the quantity of melting water. Most of the plants in the open field were damaged after 52 days of snow cover, but the plants inside the tunnel were hardly damaged. The K content in the leaves decreased under snow cover in both plots and the decrease in open field plots was greater than that that in the tunnel plots. On the other hand, Ca content decreased only in the op en field plots. The observations of leaves after snow melting with an Elect ron Prove Micro X-ray Analyzer revealed that the content of K in the necrot ized part of the leaf was lower than that in the healthy part. From these r esults, we concluded that the minerals in leaves were leached out by contin uous snow melt water and the melt water is one of the factors enhancing the snow damage.