Neem cake organic manure is the by-product obtained in the process of cold pressing of neem tree fruits and kernels, and the solvent extraction process for neem oil cake. It is a potential source of organic manure. Neem has demonstrated considerable potential as a fertilizer. For this purpose, neem cake and neem leaves are especially promising.
Neem cake organic manure protects plant roots from nematodes, soil grubs and white ants probably due to its residual limonoid content. It also acts as a natural fertilizer with pesticidal properties. Neem cake is widely used in India to fertilize paddy, cotton and sugarcane. Usage of neem cake have shown an increase in the dry matter in Tectona grandis (Teak), Acacia nilotica (Gum Arabic), and other forest trees.
Neem seed cake also reduce alkalinity in soil, as it produces organic acids on decomposition. Being totally natural, it is compatible with soil microbes, improves and rhizosphere microflora and hence ensures fertility of the soil. Neem Cake improves the organic matter content of the soil, helping improve soil texture, water holding capacity, and soil aeration for better root development.
Neem cake is effective in the management of insects and pests. The bitter principles of the soil and cake have been reported to have seven types of activities (a) antifeedant (b) attractant (c) repellent (d) insecticide (e) nematicide (f) growth disruptor and (g) antimicrobial.
The cake contains salannin, nimbin, azadirachtin and azadiradione as the major components. Of these, azadirachtin and meliantriol are used as locust antifeedants while salannin is used as an antifeedant for the housefly.