In just two years this project introduced new technology into Pakistan. Field trials produced the following results: increased productivity of the wheat-maize cropping system by 10-30%; reduced irrigation requirements for wheat and maize by 20-40% and lower risk of aquifer recharge; improve irrigation efficiency and lower risk of salinity. The permanent raised beds provide the methods and means for improving soil conditions, increasing the profitability of the wheat-maize farming system by 20-50%, and providing inexperienced farmers with immediate success that equals or betters the research results.
At Mardan experimental site around 150 km northwest of Islamabad raised beds were prepared and sown to both maize, wheat and rice in different seasons. Data were recorded for yield, water consumption and soil observations for all experiments.
In four experiments with maize the crops grown on raised beds outyielded the maize in traditional basins (29% increase) yet all received less irrigation water (11% less). This was corroborated by farmer field information for Kharif (summer) 2000 where beds yielded 3.45 tonnes per hectare (38% more than the basins) yet the irrigation time per ha was 36% less. Thus gains in water use efficiency were substantial. Some reasons for greater yield on beds were less waterlogging damage and fewer weeds.
Follow-on observations of the experimental sites have shown that over four years summer maize yields on beds yielded 54% higher than on the flat while using 33% less irrigation water. Wheat crops grown on raised beds over a three-year period yielded only 3% above those on the flat, but they needed 37% less water. Nearby farmers who have adopted raised beds are achieving similar efficiency gains with the new system.
These achievements were possible because the machinery required for this technology was successfully downsized to match the small size of paddocks and tractors in Pakistan; and developed to install, seed and renovate raised beds.
In addition, the field monitoring data in Australia, although only exploratory and compromised by the dry seasons, showed indications that salinity may be reduced and controlled in loosened raised beds that have salt levels low enough for plants to grow. This, too, was reinforced by other data. The simulation modelling illustrated that loose soil conditions will substantially reduce capillary rise (and by implication salinity). This modelling work has provided the theoretical basis for selecting soil management treatments for a separate project in Western Australia to adapt raised bed farming to waterlogged and saline sites and so return them to profitable production.