Field scale analyses of typical conventional practices for rice-wheat production showed large gaps between water demand and supply patterns. The average water input to rice was estimated as 1458 mm against the potential crop water requirement of 532 mm. This resulted in a low gross depleted fraction of 0.40 indicating that about 60 % of water was not used in rice evapotranspiration and mainly left the root zone as seepage and deep percolation flows.

In contrast, farmers tend to under-irrigate the wheat crop and try to best utilize rainfall by optimizing their irrigation schedules. The field scale average water productivity, WP_GI (grain yield per unit of gross inflow), was estimated as 0.23 Kg/m3 for rice and 1.48 Kg/m3 for wheat. This indicates that about 4.35 m3 of supplied water was used to produce 1 kilogram of paddy rice and only 0.675 m3 for 1 Kg of wheat.

The farm level comparison showed large variations in water productivity (WP_GI) among the sample farms, which ranged from 0.19-0.32 Kg/m3 for rice and 0.93-1.39 Kg/m3 for wheat. These variations under similar climatic, soil and water quality regimes could be mainly attributed to differences in agronomic and water management practices. The comparison of four sample watercourses showed that physical and economic water productivities were higher for areas with diversified cropping patterns and greater adoption of laser land leveling and zero tillage technologies.

The impacts of these technologies on water table and groundwater quality were not apparent due to relatively small areas under adoption compared to large areal extent of the contiguous groundwater reservoir system of rice-wheat areas, although the groundwater table has a slightly declining trends.

Evaluation of rice-wheat crop establishment methods indicated that the direct seeding of rice and bed planting of rice and wheat promise considerable reductions in total irrigation water applications. However, lower yields were obtained with these methods compared to conventional practices and pose a major hurdle in adoption by the farming community. Further efforts are required to devise suitable local solutions for improved weed management, seed drilling machinery and to develop farmer experience with agronomic practices and irrigation scheduling. Better performance of canal water delivery plus good conjunctive use of groundwater could help in achieving better results in the farmers' fields.

The successful development of machinery for crop residue management could further facilitate the developments of the new technologies for rice-wheat systems. Higher land and water productivity and increased net income has attracted farmers to adopt zero tillage technology. However, financial problems, lack of machinery, lack of familiarity are major constraints to accelerating the adoption of new technologies among small farmers. Formulation of a suitable policy framework and actions for the promotion of promising Resource Conservation Technologies is required.

Farmers in Pakistan's Punjab and many parts of South Asia have opted to increase economic returns from rice production by diverting large amounts of fresh water. They are more concerned to increase land productivity to ensure enhanced farm incomes and food security as compared to focusing efforts for improved water productivity. Therefore more research and development efforts are needed to realize the dual goals of increased water and land productivity using innovative water management techniques for rice-wheat systems. The study shows that the resource conservation technologies result in water savings at field level but whether these can be translated into real water savings at system scale is not yet well understood. The up-scaled adoption of resource conservation technologies is likely to result in complex interactions among various water balance components, therefore, the impact of these technologies on real water savings and water productivity needs to be further evaluated at various scales of an irrigation system/river basin.