Status and Impact of Organic Matter Fractions on Yield, Uptake and Available Nutrients in a Long-Term Fertilizer Experiment

An investigation was carried out to study the status and content of humic and fulvic acid fractions of soil organic matter and their effect on crop yield, availability and uptake of nutrients by crops in the Long Term Fertilizer Experiment in Tamil Nadu Agricultural University, Coimbatore, in progress since 1972. Continuous cultivation with addition of 100 per cent optimal level of NPK along with 10 t of FYM ha⁻¹ enhanced the organic matter fractions. Humic acid content was higher than fulvic acid and the content of both increased with depth. They contributed significantly in predicting the yield, N, P and K uptake by all the three crops of the sequence.