ABSTRACT
Management Approach ..................................................................... 358 8.3.3 Use of NIT in Integrated Nutrient Management Studies.................. 359 8.3.4 Use of NIT in Water Management Studies in Agriculture ............... 371
8.3.4.1 Introduction ........................................................................ 371 8.3.4.2 Use of the SMNP in Water Use Ef…ciency Studies ........... 372 8.3.4.3 Use of Stable Isotopes for Determining Water Used by
Plants in Agroecosystems .................................................. 373 8.3.4.4 Use of Carbon Isotope Discrimination in Plants as a
Tool for Assessing Plant WUE .......................................... 374
The present world population of 6.7 billion is expected to reach 8 billion by the year 2020. Most of the population increases will occur in developing countries, where the majority depend upon agriculture for their livelihoods. Against this background of projections of increased population growth and pressure on the worldwide availability of land and water resources, many developing countries will face major challenges to achieving sustainable food security considering their available per capita land area, the severe scarcity of fresh water resources, and particular infrastructure and socioeconomic conditions [Pinstrup-Andersen 1999; Lal 2000]. This scenario is further compounded by increased global land degradation, particularly increased risks of soil erosion and deserti…cation in sub-Saharan Africa and South Asia [Scherr 1999].
