Abstract
A Iysimeter study was conducted during 1997-2000 at green house of Soil Chemistry Section, Ayub Agricultural Research Institute, Faisalabad to assess the effect of varying irrigation frequencies on soil moisture contents, leaching of solutes, yield, water use efficiency (WUE) and N uptake by maize (Zea mays L) in fully controlled and monitored conditions. Three irrigation levels 3 (11), 4.5 (12) and 6 (13) acre inches were applied in permanently constructed cemented Irsimeters having dimensions 4 x 4 x 4 feet. Recommended dose of N, P20S and K20 @ 75-60-60 kg ha was applied in form of Urea, SSP and SOP respectively. Soil samples were collected before each irrigation to determine the actual moisture contents and solute (N03 - & N02 -) movement at various profile depths (i.e.0-15, 15-30, 30-60,60-90, 90-120 cm). The Results revealed that after each irrigation no leachate was obtained at the bottom of each Iysimeter which clearly indicated that there is no any pollution/leaching threat from agricultural chemicals like N03· Soil analysis data showed that moisture contents and N03-N concentration in profiles increased with increasing depths but this increase is not enough to leach down the water through the soil profile. Maize was harvested 61 days after transplanting. Fodder yield and N uptake of maize was significantly affected by irrigation levels during 1997-98 and 1998-99. WUE of the crop was statistically non-significant during 1997-98 but during 1998-99 significantly higher WUE was recorded at irrigation frequencies of 11 and 12 than 13 Key words: Irrigation frequency, water content, solute movement, calcareous, soil, maize
