Effect of phosphorus application on tea plantations in Himachal Pradesh

摘要

Phosphorus is one of the major yield-limiting nutrient in most of the Indian soils, (Bajaj and Ramamurthy, 1969) in general and acidic soils, in particular, owing to its high fixation and very low recovery. The soils of Kangra district, particularly, in the vicinity of Dhauladhar ranges are characterised as acidic soils in Which nutrient availability, especially of phosphorus is a severe problem.This has been attributed to the high content of sesquioxides (Fe&AI), which fix the phosphorus in to insoluble phosphate products (Bhattacharya and Singh, 1990). Further the absorption of phosphorus by clay and clay minerals also reduce the P availability to plants. As mentioned above, phosphorus plays an important role in plant growth, yet did not receiveadequate attention, though regional responses were discerned. In Assam, traditionally, phosphate application was restricted to once in three years, i.e., during the year of pruning @ 20 kg/ha/yr (Rahman, 1977). In contrast, in the South India phosphateis applied annually by placement and depending on the length of cycle, the total quantum may vary between 160 to 270 kg/ha/yr (Rangathan and Natesan, 1983).