References
- Buyanovsky , GA and Wagner , GH . 1998 . Changing role of cultivated land in the global carbon cycle . Biol Fertil Soils , 27 : 242 – 245 .
- Gami , SK , Ladha , JK , Pathak , H , Shah , MP , Pasuquin , E , Pandey , SP , Hobbs , PR , Joshy , D and Mishra , R . 2001 . Long-term changes in yield and soil fertility in a twenty-year rice-wheat experiment in Nepal . Biol Fertil Soils , 34 : 73 – 78 .
- Katyal , JC , Rao , NH and Reddy , MN . 2001 . Critical aspects of organic matter management in the Tropics: the example of India . Nutr Cycl Agroecosys , 61 : 77 – 86 .
- Ladha , JK , Pathak , H , Padre , AT , Dawe , D and Gupta , RK . 2003 . “ Improving the productivity and sustainability of rice-wheat systems: issues and impacts ” . In Productivity trends in intensive rice-wheat cropping systems in Asia, Chapter 3 , Edited by: Ladha , JK , Hill , JE , Duxbury , JM , Gupta , RK and Buresh , RJ . 45 – 76 . Madison , WI : American Society of Agronomy .
- Nambiar , KKM . 1995 . “ Agricultural sustainability – economic environment and statistical considerations ” . In Major cropping systems in India, Chapter 4 , Edited by: Barnett , V , Pyne , R and Steiner , R . 133 – 168 . New York : John Wiley and Sons .
- Pathak , H , Ladha , JK , Aggarwal , PK , Peng , S , Das , S , Kamra , SK , Mishra , B and Sastri , ASRAS . 2003 . Trends of climatic potential and on-farm yields of rice and wheat in the Indo-Gangetic plains . Field Crops Res , 80 : 223 – 234 . Yadvinder Singh, Bijay Singh
- Ram , N . 1998 . “ Long-term soil fertility management through integrated plant nutrient supply ” . In Effect of continuous fertilizer use on soil fertility and productivity of a Mollisol, Chapter 20 , Edited by: Swarup , A , Reddy , D and Prasad , RN . 229 – 237 . Bhopal , , India : Indian Institute of Soil Science .
- Sekhon , GS . 1999 . Potassium in Indian soils and crops . Proc Indian Natl Sci Acad , B65 : 83 – 108 .
- Swarup , A . 1998 . “ Long-term soil fertility management through integrated plant nutrient supply ” . In Emerging soil fertility management issues for sustainable crop productivity in irrigated areas, Chapter 3 , Edited by: Swarup , A , Reddy , D and Prasad , RN . 54 – 68 . Bhopal , , India : Indian Institute of Soil Science .
- Yadav , RL , Dwivedi , BS , Prasad , K , Tomar , OK , Shurpal , NJ and Pandey , PS . 2000 . Yield trends, and changes in soil organic-C and available NPK in a long-term rice-wheat system under integrated use of manures and fertilizers . Field Crops Res , 68 : 219 – 246 .