EFFECT OF HUMIC ACID ON PLANT GROWTH CHARACTERS AND GRAIN YIELD OF DRIP FERTIGATED AEROBIC RICE (ORYZA SATIVA L.)

Abstract

An experiment was aimed to assess the effect of humic acid on plant growth attributes and yield of aerobic rice under conventional, drip and subsurface drip fertigation system allotted to main plot and fertiliser levels (75 and 100% RDF) with and without humic acid kept in sub plots. The results indicated that lengthier root (59.1 m hill¹), high chlorophyll content (2.66 mg g^-1), LAD (141 days), more productive tillers (680 tillers m^-2) and yield (5645 kg ha^-1) were produced under subsurface drip irrigation which was 21.0 percent increase over surface irrigation and 7.7 percent over drip irrigation system. Moreover, 100% RDF (150:50:50 NPK kg ha^-1) applied with humic acid recorded maximum root length (58.8 m hill^-1), higher chlorophyll content (2.61 mg g^-1), LAD (151 days), more filled grain percentage (69.1) and yield (5616 kg ha^-1). From this study it can be concluded that subsurface drip + 100% RDF with humic acid plants showed favourable morphological growth characters with improved yield attributes leads higher grain yield. This may be due to humic acid improve plant physiological processes by enhancing the availability of major and minor nutrients as well as enhancing the vitamins, amino acids, and also auxin, cytokinin and ABA contents of the plants.