Status and chemical fractions of zinc in Apple Orchard soils of Himachal Pradesh

Based on productivity, hill aspect and altitude, a total of 144 apple orchards (cv. Royal Delicious) located in different districts of Himachal Pradesh were selected to study the Zn status and its chemical fractions. The DTPA extractable Zn was in the optimum range in most of the surface soils, however, sub-surface soils registered Zn deficiency to the extent of 34–100 per cent in different apple growing districts of the state. Leaf analysis also revealed Zn deficiency to the tune of 25 to 90 per cent. Bulk of the native Zn (amounting to 77.8 to 90.5%) was found in the residual fraction strongly bound to the soil minerals. The amount of Zn in other fractions was in the order: acid soluble > citrate bicarbonate Dithionite soluble > organically bound > complexed > water soluble + exchangeable Zn. The favourable effect of clay content on accumulation of the WS+Ex-Zn and of organic matter on organically bound Zn was quite obvious. Except in case of WS+Ex and acid soluble Zn, the combined influence of the studied soil characteristics on Zn fractions was not discernible.