Journal of Environmental Biology

Environmental impact of nitrogen fertilization in tea eco-system

R. Saraswathy*¹, S. Suganya² and P. Singaram²

*saraswati_ciba@yahoo.co.in

¹Central Institute of Brackishwater Aquaculture (CIBA), 75, Santhome high road, R.A. Puram, Chennai-600 028, India

²Department of Soil Science, Tamil Nadu Agricultural University, Coimbatore-641 003, India

(Received: October 10, 2005 ; Revised received: May 15, 2006 ; Accepted: June 30, 2006)

Abstract: To quantify the nitrogen losses through runoff, and leaching under a tea plantation in hilly soil, a field experiment was conducted from October 2001 to October 2002 at United Planters Association of Southern India (UPASI), Coonoor in Nilgiri district. Runoff water was collected in the collection tub on most rainy days but the leachate was collected in the soil water sampler when the rainfall exceeded 150 mm. Higher nitrogen fertilization levels significantly influenced the NO₃-N concentration in both the runoff and leachate and it was likely to cause adverse environmental impact at the delivery end. The NH₄-N and NO₃-N concentrations in runoff decreased with the days after fertilizer application. NH₄-N concentration reduced from 10.27 mg/l on the 9^th day to 1.72 mg/l on the 34^th day after fertilizer application. NO₃-N concentration reduced from 23.5 mg/l on the 9^th day to 4.32 mg/l on the 34^th day after fertilizer application. Nitrogen loss varied depending on the quantity of rainfall and runoff. The NO₃-N concentration in the leachate increased with increase in depth (18.06 mg/l at 22.5 cm depth to 20.98 mg/l at 45 cm depth) whereas NH₄-N concentration decreased with increase in depth (6.32 mg/l at 22.5 cm depth to 5.79 mg/l at 45 cm depth.

 

Key words :? Clay loam, Runoff, Leachate, NH₄-N, NO₃-N concentration

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