CROP RESEARCH

Field experiment was conducted in three years’ old mulberry (Morus alba L.) garden in black cotton soils of Research Extension Centre, Central Silk Board, Vikarabad during 2006–08 to study the efficacy of fly ash and farm yard manure and their interactions on soil enzymes, mulberry leaf yield and quality through bioassay (silkworm rearing). The findings revealed that the maximum mulberry yield (62.90 MT/ha/year), leaf moisture content (72.50%) and leaf moisture retention capacity (71.35%) were registered due to the application of fly ash (10 MT/ha/year) and farm yard manure (15 MT/ha/year), which were on par with the combined effect of fly ash (15 MT/ha/year) and farm yard manure (15 MT/ha/year). With regard to silkworm rearing, the minimum larval duration (25.25 days), maximum 10 larval weight (52.60 g), effective rate of rearing (94.95%), single cocoon weight (2.150 g), single shell weight (0.431 g) and single shell ratio (20.25%) were recorded with the application of fly ash (10 MT/ha/year) and farm yard manure (15 MT/ha/year), of which on par with the associative effect of fly ash (15 MT/ha/year) and farm yard manure @ 15 MT/ha/year. In the case of soil enzymes, the highest urease, dehydrogenase and cellulase activities were recorded due to application of fly ash @ 15 MT/ha/year and farm yard manure @ 15 MT/ha/year at 30 days after treatment (DAT) (4.49 mg of NH₄⁺ released/g soil/h, 5.37 mg of TPF produced/g soil/d and 3.51 mg of glucose released/g soil/d), at 60 DAT (4.81 Mg of NH₄⁺released/g soil/h; 5.47 mg of TPF produced/g soil/d and 2.97 mg of glucose released/g soil/d), at (70 days) harvest (2.54 mg of NH₄⁺ released/g soil/h; 3.09 mg of TPF produced/g soil/d and 2.17 mg of glucose released/g soil/d), respectively, which was on par with combined effect of fly ash @ 10 MT/ha/year) and farm yard manure @ 10 MT/ha/year and significantly higher over control. The acid and alkaline phosphatase activities were not influenced by fly ash doses at all stages viz., 30, 60 DAT and at harvest (70 days). However, it was significantly influenced by farm yard manure application.