HomeInternational Rice Research Notesvol. 30 no. 2 (2005)

Productivity of irrigated rice as influenced by leaf color chart-based N management in the Tungabhadra Project (TBP) area in Karnataka, India

D.p. Biradar | A. Shivakumar | A. Nagappa | M.a. Basavanneppa

Discipline: Agriculture



The use of proper doses of nutrients, N in particular, is important to attain high yields and efficient nutrient use in intensive rice ecosystems. Poor N-use efficiency by rice is largely because of N losses in the rice ecosystem through NH3 volatilization, denitrification, runoff, and leaching. Any method that promotes N-use efficiency would help rice farmers immensely by reducing their N fertilizer cost. In a survey conducted in the Tungabhadra Project (TBP) area, it was found that farmers applied a high dose of N (230 kg ha-1) and only 35.2 kg P ha-1 and 24.9 kg K ha-1. Too much N application, along with inadequate P and K fertilizers, led to an imbalance in fertilizer use in the TBP area. This practice resulted in higher pest and disease incidence and serious lodging in rice. Unbalanced fertilizer use led to high pesticide use to control pests, which translated into more pesticide expenditures. Lodging caused reduced yield and poor grain quality. In addition, the excess N leached, polluting water sources over time. This has been occurring in the TBP area in recent years.