Nutritional Requirement of Hevea:II.Effect of N,P and K on Dry Matter Yield,Nutrient Content and Uptake of Nutrients by Rubber Seedlings in Assam

摘要

The influence of N,P and K application on dry matter yield,nutrient content,uptake of nutrients,apparent nutrient recovery(ANR)and per cent yield response(PYR)by rubber seedlings(Hevea brasiliensis)under the Assam condition were studied for two consecutive years.Four levels of N(0,166,333 & 500 kg N ha~(-1))and three levels of K(0,62.5 and 125 kg K_2O ha~(-1))and their combinations were applied with three replications.The design was R.B.D.The results showed that dry matter yield of rubber seedlings was significantly increased due to N application particularly N 333 kg ha~(-1)(23.6 ton ha~(-1)).A positive increase in yield was noticed for P and K.Highest yield was recorded under the treatment combination N_333 P 250 kg ha~(-1).Application of N,P and K significantly increased their content in plants and uptake of nutrients as well.ANR(141.47 %)and PYR(121.27 %)was highest when nitrogen was applied 333 kg N ha~(-1)in comparison to control plots.Application of higher doses of P and K showed better response both for ANR and PYR.In all the cases PYR was found positive except for P(125 kg P_2O_5 ha~(-1))indicating lower requirement of P than that of N and K during seedling nursery stage.Application of N,P and K showed improvement of available nutrient status of soil,which may subsequently,increase the growth and biomass yield of the seedlings compared to control plots.