Impact of Repeated Applications of Chemical Fertilizers in Mulberry Cropping System on Soil Health, Leaf Production and Rearing Parameters of Silkworm, Bombyx mori L.

Aim: To find out the effect of continuous use of chemical fertilizers in the mulberry ecosystem.

Study Design: CRBD

Place and Duration of Study: Potential sericulture cluster in Erode district of Tamil Nadu, India, between January 2015 and December 2016.

Methodology: Standard methodologies used to study the physical, chemical and biological properties of soil, foliar constituents of mulberry and rearing parameters of the silkworm.

Results: Repeated applications of chemical fertilizers in mulberry cropping system registered more bulk density (1.57 mg m-3), PH (9.22) and EC (0.361 dS/m) and reduced field capacity (23.47%), water holding capacity (39.15%), porosity (35.60%), infiltration rate (3.20 cm/hr-1) and the population of soil microbes viz. bacteria (19.66 cfu/g), fungi (13.00 cfu/g) and actinomycetes (9.33 cfu/g) when compared to the respective values of manuring practices with 100% organic inputs (1.23 mg m-3, 7.39, 0.106 dS/m & 31.25%, 58.59%, 49.25% & 7.68 cm/hr-1 and 68.00 cfu/g, 25.33 cfu/g & 21.33 cfu/g). Lowest contents of available N (105 kg/h), P (9.75 kg/ha & K 318.70 kg/ha recorded in the gardens repeatedly received inorganic fertilizers than organic farming system (283.73, 35.81 & 340.12 kg/ha of NPK) which reflected adversely on mulberry leaf yield (43.41 MT/ha/yr) and moisture content (60.53%), moisture retention capacity (63.66%), total protein (16.83%) and total carbohydrates (28.03%) whereas in organic farming the respective values (55.80 MT/ha/yr, 71.33%, 93.36%, 21.60% & 36.23%) were found superior. Organic manuring practices registered better cocoon yield (88.348 kg/100 dfls) and average cocoon productivity (3286 kg/ha of mulberry garden) when compared to chemical farming (55.595 kg/100 dfls and 3286 kg/ha of mulberry garden).

Conclusions: A holistic approach should be made for creating awareness among the sericulture farmers and popularizing organic farming strategies to maintain soil health, improve production of quality mulberry leaf and sustainable production of silk.