Effect of weather and application of primary nutrients and liming to ber (Ziziphus mauritiana) on winter season (aghani) kusmi lac production

Abstract

An experiment was carried out during 2007-08 to 2009-10 at the research farm of Indian Institute of Natural Resins and Gums, Ranchi (23o23’N longitude, 85o23’ E latitude and 650 m above MSL) to find out the effects of different primary nutrients (N, P2O5 and K2O) and liming on established plantation of ber (Ziziphus mauritiana Lam.) for the production of winter season (aghani) kusmi crop of Kerria lacca (Kerr). Treatments comprised of four levels of N (0,100, 200 and 400 g/ tree), two levels each of P2O5 (0 and 150 g/ tree), K2O (0 and 150 g/ tree) and liming (liming and no liming). Randomized Block Design was used in three replications and effect of years (weather variation) was estimated as the fifth factor. Potassium application led to reduction in male population by 3%. Significant interaction effect in between year and potassium application was noticed on lac yield ratio (output/ input). Potassium application with liming (at soils of higher pH) was found detrimental to lac production, while its application under low soil pH conditions increased lac yield ratio significantly. An increase in yield ratio to the tune of 97% was observed in potassium application on soil pH 4.5 as compared to that in pH 5.6. Lower adsorption of potassium in exchange complex under lower soil pH conditions might have increased the potassium availability to the plant. Eventually, increased translocation of assimilate might have positively affected the nutrition of lac insect and lac yield ratio.