- Dobermann, A. arid White, P.E (1999). Nut. eye. Agroecosyst. 53: 56~63.
- Singh, U. and Buresh,~.J .. (1994). In: Proc. 15th World Congress of Soil Scien/;e, Acapulco, Mexico, pp. 643-653.
Results of experiments conducted to standardise the critical leaf colour chart values in comparison with SPAD based N management techniques for transplanted rice (in Cauvery new delta zone) indicated that in dry season leaf colour chart colour shade 4 based nitrogen management and in wet season leaf colour chart colour shade 5 based nitrogen management recorded higher grain yield and found comparable with SPAD 37 based nitrogen nitrogen management.