Effect of controlled sprinkler chemigation on wheat crop in a sandy soil

A two-year experiment was conducted in the desert west of the Nile Delta to study the effect of applying fertilizers and other agronomic chemicals through sprinkler irrigation water (a technique referred to as chemigation) on wheat grain yield. Experiment included three levels of irrigation inputs, namely: I1 = potential evapotranspiration rate (ETp), I2 = 0.8 ETp and I3 = 0.6 ETp, and included two application method of fertilizers and herbicide (chemication and traditional). Applying chemigation resulted in significant increase in grain yield, ranging between 9.9% and 50.0% with averages of 43.2% and 14.5% over the first and second seasons, respectively. Irrigation treatment I1 produced higher grain yield than the other two irrigation treatments both under traditional and chemigation methods as a result of better fertilizer distribution in the root zone. Grain yield associated with combined I1 and chemigation was highest of all treatments and was greater than Egypt's national average by 14% and 9% for seasons 1 and 2, respectively. Chemigation resulted in more uniform distribution of nitrate-nitrogen throughout the root zone with nitrate levels falling within safe limits. Concentrations under traditional application resulted in lower levels in upper soil and greater levels at deeper soil of the root zone exceeding safe limits and subjecting the soil and groundwater to contamination hazards. For both N and K fertilizers, fertilizer use efficiency was greater under chemigation than under traditional application. Efficiencies increased with increasing irrigation water, apparently due to better fertilizer distribution. Applying herbicides with sprinkler irrigation water reduced weed infestation from 48% to 6.5%. As a result of improved yield under chemigation, an increase in revenue per hectare of 112.6% was achieved.