Silkworm rearing is taken up by harvesting mulberry shoots at regular intervals.
Hence the plant requires adequate nutrition for its growth after each pruning to obtain optimum leaf yield and quality.
It is estimated that 350:140:140 kgs. of NPK / hectare / year need to be applied in five split doses.
If a farmer meets this requirement through chemical fertilizer, he has to apply around 3,000 kgs every year.
Application of excess chemical fertilizers not only pollutes the soil but also adversely affects the beneficial flora and fauna.
Hence adoption of organic farming is important to conserve the soil health in mulberry ecosystem.
Farm yard manure
Farm yard manure increases soil fertility as well as water holding capacity and promotes growth of beneficial organisms. It is recommended to apply 20 metric tonnes per hectare a year in two split doses.
Bacteria Azotobacter and Azospirillum naturally supply nitrogen to the plants by biological nitrogen fixation and enhance the growth and the phosphobacteria converts the phosphate fixed in the soil as non-available form into available form. A mycorrhizal fungus (VAM) is also found beneficial.
A sericulture farmer can easily get around 12-15 metric tonnes of organic residues annually from a hectare of mulberry plantation through silkworm excreta, unfed leaves, shoots, weeds etc. which could be converted into vermocompost which is superior in nutritional value than FYM and compost.
A leguminous crop of short duration with high bio-mass production is cultivated as inter crop for green manuring and mulched with soil to enrich the fertility.
In mulberry, daincha is recommended for black soil and sunhemp for red soil.
Application of insecticides with high toxicity results in prolonged residual effects in mulberry gardens and is to be restricted because of high sensitivity of silkworms.
Further, indiscriminate use of chemical insecticides develops resistance in insect pests as well as destroys their natural enemies resulting in outbreak of minor pests.