Phosphorus enriched organic fertilizer, an effective P source for improving yield and bioactive principle of Senna (Cassia angustifolia Vhal.)

Abstract

A pot culture experiment was conducted for two consecutive years in the late rainy season to evaluate the efficiency of rock phosphate charged compost as an organic P fertilizer source in senna. A fixed dose of P (40 kg ha−1), considered optimum for quality produce was supplied from different sources like Di-ammonium phosphate (DAP), Single Super Phosphate (SSP), Rock phosphate (RP) and RP charged compost (RPCC). Fresh and dry weight of leaves and pods per plant were recorded while sennoside content in leaves and pods samples were analyzed. Total fresh and dry herbage yield (leaf + pod) was significantly higher under different P treatments than the control. Application of RP, SSP, DAP and RPCC increased fresh herbage yield up to 6.7, 22.6, 35.1 and 48.1%, respectively over the control. Sennoside content did not respond to all P sources, but application of RPCC improved sennoside content in herbage. The highest herbage yield and sennoside content was recorded under RPCC application. Available P and microbial biomass P in soil after harvesting of crop was significantly higher under RPCC application but on par with DAP application. Both acid and alkaline phosphatase activities in soil were influenced by P sources, while alkaline phosphatase found significantly higher with RPCC application. So, it can be concluded from the study that enriched compost effectively supplement costly chemical fertilizer like DAP as a P source. The result from the study may be recommended for efficient P management in both commercial as well as organic cultivation of senna.