Nematode population density in soil is one of the major factors which limits agricultural crop yield. The population density increases due to factors like availability of favourable host, soil moisture, soil temperature and soil types.
Department of Nematology, Tamil Nadu Agricultural University, is taking various measures to reduce the nematode population in soil. Dr. M. Sivakumar and Dr. S. Subramanian, Professors of TNAU, explained that generally, a population level of one infective juvenile per cc of soil is the ETL for majority of nematodes. For some endoparasites like lesion nematodes the ETL level is still as low as 0.5 nematodes per cc soil.
The population densities, especially that of females, increase when the food availability is more, whereas the female population is greatly reduced during adverse conditions when the food availability is less. During such conditions more males will be produced which are non feeding ones. They remain alive for about a day or two and then die.
Normally the population of plant-parasitic nematodes are high during the crop, seasons like Kharif and Rabi where the nematode gets more nutrient supply in soil. The populations are low during fallow periods and also during severe drought conditions.
Ways of reducing nematode population in the soil without deterioration of soil health.
Amendment the soil with organic additions is one of the important methods of reducing the soil nematode populations. Organic methods of amendment include:- Farm Yard Manure, oiled cakes, press mud, green manuring, green leaf manuring, etc.
How organic amendments work to reduce nematodes in soil:
In order to sustain the soil health, the soil is to be properly maintained with sufficient organic amendments which form the substrate for the growth of nematode-antagonistic micro flora.
Department of Nematology, Tamil Nadu Agricultural University, is taking various measures to reduce the nematode population in soil. Dr. M. Sivakumar and Dr. S. Subramanian, Professors of TNAU, explained that generally, a population level of one infective juvenile per cc of soil is the ETL for majority of nematodes. For some endoparasites like lesion nematodes the ETL level is still as low as 0.5 nematodes per cc soil.
The population densities, especially that of females, increase when the food availability is more, whereas the female population is greatly reduced during adverse conditions when the food availability is less. During such conditions more males will be produced which are non feeding ones. They remain alive for about a day or two and then die.
Normally the population of plant-parasitic nematodes are high during the crop, seasons like Kharif and Rabi where the nematode gets more nutrient supply in soil. The populations are low during fallow periods and also during severe drought conditions.
Ways of reducing nematode population in the soil without deterioration of soil health.
Amendment the soil with organic additions is one of the important methods of reducing the soil nematode populations. Organic methods of amendment include:- Farm Yard Manure, oiled cakes, press mud, green manuring, green leaf manuring, etc.
How organic amendments work to reduce nematodes in soil:
- The organic amendments on decomposition release enormous heat which are sufficient to kill nematodes.
- During decomposition of organic manure, a lot of metabolic by-products and organic acids are produced which are toxic to nematodes.
- Organic amendments improve the structure and texture of the soil, and the alternations are harmful to nematodes.
- The metabolic byproducts of organic amendments help to improve the growth of nematode-antagonistic micro flora in the soil.
- Some of the amendments like neem cakes are toxic to nematodes due to the flavanoids present in the soil.
In order to sustain the soil health, the soil is to be properly maintained with sufficient organic amendments which form the substrate for the growth of nematode-antagonistic micro flora.