Biofilmed Biofertilizers can halve chemical fertilizer use in young tea of Sri Lanka

A field trial with two biofilmed biofertilizer (BFBF) formulations applied to young tea was conducted for two years in low country wet zone of Sri Lanka. Treatments included; two BFBF formulations (F3A & F3B) alone, each coupled with 50% of the recommended chemical fertilizer dose (T200), 100% of T200 alone, and 50% of T200 alone. In the first year, tea yields were higher with both BFBF formulations when coupled with 50% T200 (i.e. F3A + 50% T200 & F3B + 50% T200), than when 100% T200 alone was used. However, in the second year, 100% T200 yielded more than the previous year, while there was no difference with the yields of both BFBF formulations coupled with 50% T200 (i.e. BFBFs + 50% T200), though they yielded less than the previous year. Both BFBF formulations when used alone, yielded comparable to 50% T200 in both years. It is apparent that plant water conservation has contributed to the positive results of the BFBFs, as reflected from leaf transpiration data. Plant growth promoting effect of particularly, F3B + 50% T200 over 100% T200 could be seen in the increases in height and girth before second centering. Soil organic carbon accumulation during the two years was higher with the use of BFBFs + 50% T200 than 100% T200, but soil nitrogen accumulation showed an opposite trend. It is evident from this study that the BFBF formulations can compensate 50% T200 in young tea of the region tested.