Abstract:
The present study ‘screening plant materials for nitrification inhibition properties and testing field performance of promising materials’ was conducted during May 1984 to November 1985 at the College of Horticulture, Vellanikkara, Trichur. A total of 17 materials were used for screening using already proved nitrification inhibition materials like N-Serve and neem cake as reference. Nitrification rate in the soil was found to be very low and there was no appreciable conversion of NH+4 form to NO 3. Since there was no significant difference in the NH+4 content between treatments due to the naturally low rate of nitrification, selection of promising materials possessing nitrification inhibition property could not be done. Attempts were made to locate the factors that resulted in the low rate of nitrification in the soil. Organic matter content, pH, cropping history, amount of NH+4– N build up in the soil, incubation conditions and low microbial population were not indicated as responsible for the noted low degree of nitrification. In red and black soils of Coimbatore, nitrification was appreciable and there was fast disappearance of NH+4–N. Data on various growth parameters like mean, height, LAI and dry matter production of the test crop. Fodder maize, did not show any treatment difference. The yield in the treatment which received no fertiliser nitrogen was significantly lower than in other treatments. Similar were the results on nitrogen content of plant parts at various stages and those on total nitrogen uptake. The addition of materials used as nitrification inhibitors did not show any added advantage over untreated urea since the degree of nitrification in the soil was not appreciable.
