Organic nutrient management protocol for cultivation of ‘Bombai’ litchi

An investigation was carried out under subtropical conditions of West Bengal, India (22.43°N latitude, 88.34°E longitude) at the Horticultural Research Station of the University to standardize the organic nutrient management protocol for litchi. Various organic sources viz., farm yard manure at 60 kg/tree/year, poultry manure at 21.4 kg/tree/year, vermicompost at 42.86 kg/tree/year and neem cake at 20.28 kg/tree/year along with various biofertilizer combinations (Azotobacter, Azospirillum, phosphorous solubilizers and potash mobilizers each at 100 g/tree/ year) were tested on 32-year-old litchi cultivar ‘Bombai’. These trees were not fertilized with any nutrients for five years prior to the experiment. The different doses of nutrients were calculated based on the 50% of the potassium requirement of the crop in this region and were applied in two split doses in January (after fruit set) and July (after fruit harvest). Application of farm yard manure + Azotobacter + phosphorous solubilizers + potash mobilizers resulted in greater fruit weight (24.73 g). The number of fruits (2556) and fruit yield (61.59 kg compared to 23.94 kg in control) per tree were greater with vermicompost + Azotobacter + phosphorous solubilizers + potash mobilizers. Treatment combinations with farm yard manure + Azotobacter + phosphorous solubilizers + potash mobilizers showed higher total soluble solids (17.79°Brix) and total sugar content (17.57%), whereas vitamin C content (53.48 mg/100 g pulp) was higher where a combination of neem cake + Azospirillum + phosphorous solubilizers + potash mobilizers was applied. Application of nutrients through organic source along with biofertilizers improved soil health by increasing the microbial population in the rhizosphere. Addition of biofertilizers along with organic manure was more effective in enhancing fruit growth parameters in litchi than the use of organic manure alone. Application of vermicompost at (42.86 kg/tree/year) + Azotobacter + phosphorous solubilizers + potash mobilizers each at 100 g/tree/year in two split doses (January and July) is recommended for the organic production of the ‘Bombai’ litchi.